1 //===- MipsISelLowering.cpp - Mips DAG Lowering Implementation ------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the interfaces that Mips uses to lower LLVM code into a
10 // selection DAG.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MipsISelLowering.h"
15 #include "MCTargetDesc/MipsBaseInfo.h"
16 #include "MCTargetDesc/MipsInstPrinter.h"
17 #include "MCTargetDesc/MipsMCTargetDesc.h"
18 #include "MipsCCState.h"
19 #include "MipsInstrInfo.h"
20 #include "MipsMachineFunction.h"
21 #include "MipsRegisterInfo.h"
22 #include "MipsSubtarget.h"
23 #include "MipsTargetMachine.h"
24 #include "MipsTargetObjectFile.h"
25 #include "llvm/ADT/APFloat.h"
26 #include "llvm/ADT/ArrayRef.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/ADT/Statistic.h"
29 #include "llvm/ADT/StringRef.h"
30 #include "llvm/ADT/StringSwitch.h"
31 #include "llvm/CodeGen/CallingConvLower.h"
32 #include "llvm/CodeGen/FunctionLoweringInfo.h"
33 #include "llvm/CodeGen/ISDOpcodes.h"
34 #include "llvm/CodeGen/MachineBasicBlock.h"
35 #include "llvm/CodeGen/MachineFrameInfo.h"
36 #include "llvm/CodeGen/MachineFunction.h"
37 #include "llvm/CodeGen/MachineInstr.h"
38 #include "llvm/CodeGen/MachineInstrBuilder.h"
39 #include "llvm/CodeGen/MachineJumpTableInfo.h"
40 #include "llvm/CodeGen/MachineMemOperand.h"
41 #include "llvm/CodeGen/MachineOperand.h"
42 #include "llvm/CodeGen/MachineRegisterInfo.h"
43 #include "llvm/CodeGen/RuntimeLibcalls.h"
44 #include "llvm/CodeGen/SelectionDAG.h"
45 #include "llvm/CodeGen/SelectionDAGNodes.h"
46 #include "llvm/CodeGen/TargetFrameLowering.h"
47 #include "llvm/CodeGen/TargetInstrInfo.h"
48 #include "llvm/CodeGen/TargetRegisterInfo.h"
49 #include "llvm/CodeGen/ValueTypes.h"
50 #include "llvm/IR/CallingConv.h"
51 #include "llvm/IR/Constants.h"
52 #include "llvm/IR/DataLayout.h"
53 #include "llvm/IR/DebugLoc.h"
54 #include "llvm/IR/DerivedTypes.h"
55 #include "llvm/IR/Function.h"
56 #include "llvm/IR/GlobalValue.h"
57 #include "llvm/IR/Type.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/MC/MCContext.h"
60 #include "llvm/MC/MCRegisterInfo.h"
61 #include "llvm/Support/Casting.h"
62 #include "llvm/Support/CodeGen.h"
63 #include "llvm/Support/CommandLine.h"
64 #include "llvm/Support/Compiler.h"
65 #include "llvm/Support/ErrorHandling.h"
66 #include "llvm/Support/MachineValueType.h"
67 #include "llvm/Support/MathExtras.h"
68 #include "llvm/Target/TargetMachine.h"
69 #include "llvm/Target/TargetOptions.h"
70 #include <algorithm>
71 #include <cassert>
72 #include <cctype>
73 #include <cstdint>
74 #include <deque>
75 #include <iterator>
76 #include <utility>
77 #include <vector>
78 
79 using namespace llvm;
80 
81 #define DEBUG_TYPE "mips-lower"
82 
83 STATISTIC(NumTailCalls, "Number of tail calls");
84 
85 static cl::opt<bool>
86 NoZeroDivCheck("mno-check-zero-division", cl::Hidden,
87                cl::desc("MIPS: Don't trap on integer division by zero."),
88                cl::init(false));
89 
90 extern cl::opt<bool> EmitJalrReloc;
91 
92 static const MCPhysReg Mips64DPRegs[8] = {
93   Mips::D12_64, Mips::D13_64, Mips::D14_64, Mips::D15_64,
94   Mips::D16_64, Mips::D17_64, Mips::D18_64, Mips::D19_64
95 };
96 
97 // The MIPS MSA ABI passes vector arguments in the integer register set.
98 // The number of integer registers used is dependant on the ABI used.
99 MVT MipsTargetLowering::getRegisterTypeForCallingConv(LLVMContext &Context,
100                                                       CallingConv::ID CC,
101                                                       EVT VT) const {
102   if (!VT.isVector())
103     return getRegisterType(Context, VT);
104 
105   return Subtarget.isABI_O32() || VT.getSizeInBits() == 32 ? MVT::i32
106                                                            : MVT::i64;
107 }
108 
109 unsigned MipsTargetLowering::getNumRegistersForCallingConv(LLVMContext &Context,
110                                                            CallingConv::ID CC,
111                                                            EVT VT) const {
112   if (VT.isVector())
113     return divideCeil(VT.getSizeInBits(), Subtarget.isABI_O32() ? 32 : 64);
114   return MipsTargetLowering::getNumRegisters(Context, VT);
115 }
116 
117 unsigned MipsTargetLowering::getVectorTypeBreakdownForCallingConv(
118     LLVMContext &Context, CallingConv::ID CC, EVT VT, EVT &IntermediateVT,
119     unsigned &NumIntermediates, MVT &RegisterVT) const {
120   // Break down vector types to either 2 i64s or 4 i32s.
121   RegisterVT = getRegisterTypeForCallingConv(Context, CC, VT);
122   IntermediateVT = RegisterVT;
123   NumIntermediates =
124       VT.getFixedSizeInBits() < RegisterVT.getFixedSizeInBits()
125           ? VT.getVectorNumElements()
126           : divideCeil(VT.getSizeInBits(), RegisterVT.getSizeInBits());
127   return NumIntermediates;
128 }
129 
130 SDValue MipsTargetLowering::getGlobalReg(SelectionDAG &DAG, EVT Ty) const {
131   MachineFunction &MF = DAG.getMachineFunction();
132   MipsFunctionInfo *FI = MF.getInfo<MipsFunctionInfo>();
133   return DAG.getRegister(FI->getGlobalBaseReg(MF), Ty);
134 }
135 
136 SDValue MipsTargetLowering::getTargetNode(GlobalAddressSDNode *N, EVT Ty,
137                                           SelectionDAG &DAG,
138                                           unsigned Flag) const {
139   return DAG.getTargetGlobalAddress(N->getGlobal(), SDLoc(N), Ty, 0, Flag);
140 }
141 
142 SDValue MipsTargetLowering::getTargetNode(ExternalSymbolSDNode *N, EVT Ty,
143                                           SelectionDAG &DAG,
144                                           unsigned Flag) const {
145   return DAG.getTargetExternalSymbol(N->getSymbol(), Ty, Flag);
146 }
147 
148 SDValue MipsTargetLowering::getTargetNode(BlockAddressSDNode *N, EVT Ty,
149                                           SelectionDAG &DAG,
150                                           unsigned Flag) const {
151   return DAG.getTargetBlockAddress(N->getBlockAddress(), Ty, 0, Flag);
152 }
153 
154 SDValue MipsTargetLowering::getTargetNode(JumpTableSDNode *N, EVT Ty,
155                                           SelectionDAG &DAG,
156                                           unsigned Flag) const {
157   return DAG.getTargetJumpTable(N->getIndex(), Ty, Flag);
158 }
159 
160 SDValue MipsTargetLowering::getTargetNode(ConstantPoolSDNode *N, EVT Ty,
161                                           SelectionDAG &DAG,
162                                           unsigned Flag) const {
163   return DAG.getTargetConstantPool(N->getConstVal(), Ty, N->getAlign(),
164                                    N->getOffset(), Flag);
165 }
166 
167 const char *MipsTargetLowering::getTargetNodeName(unsigned Opcode) const {
168   switch ((MipsISD::NodeType)Opcode) {
169   case MipsISD::FIRST_NUMBER:      break;
170   case MipsISD::JmpLink:           return "MipsISD::JmpLink";
171   case MipsISD::TailCall:          return "MipsISD::TailCall";
172   case MipsISD::Highest:           return "MipsISD::Highest";
173   case MipsISD::Higher:            return "MipsISD::Higher";
174   case MipsISD::Hi:                return "MipsISD::Hi";
175   case MipsISD::Lo:                return "MipsISD::Lo";
176   case MipsISD::GotHi:             return "MipsISD::GotHi";
177   case MipsISD::TlsHi:             return "MipsISD::TlsHi";
178   case MipsISD::GPRel:             return "MipsISD::GPRel";
179   case MipsISD::ThreadPointer:     return "MipsISD::ThreadPointer";
180   case MipsISD::Ret:               return "MipsISD::Ret";
181   case MipsISD::ERet:              return "MipsISD::ERet";
182   case MipsISD::EH_RETURN:         return "MipsISD::EH_RETURN";
183   case MipsISD::FMS:               return "MipsISD::FMS";
184   case MipsISD::FPBrcond:          return "MipsISD::FPBrcond";
185   case MipsISD::FPCmp:             return "MipsISD::FPCmp";
186   case MipsISD::FSELECT:           return "MipsISD::FSELECT";
187   case MipsISD::MTC1_D64:          return "MipsISD::MTC1_D64";
188   case MipsISD::CMovFP_T:          return "MipsISD::CMovFP_T";
189   case MipsISD::CMovFP_F:          return "MipsISD::CMovFP_F";
190   case MipsISD::TruncIntFP:        return "MipsISD::TruncIntFP";
191   case MipsISD::MFHI:              return "MipsISD::MFHI";
192   case MipsISD::MFLO:              return "MipsISD::MFLO";
193   case MipsISD::MTLOHI:            return "MipsISD::MTLOHI";
194   case MipsISD::Mult:              return "MipsISD::Mult";
195   case MipsISD::Multu:             return "MipsISD::Multu";
196   case MipsISD::MAdd:              return "MipsISD::MAdd";
197   case MipsISD::MAddu:             return "MipsISD::MAddu";
198   case MipsISD::MSub:              return "MipsISD::MSub";
199   case MipsISD::MSubu:             return "MipsISD::MSubu";
200   case MipsISD::DivRem:            return "MipsISD::DivRem";
201   case MipsISD::DivRemU:           return "MipsISD::DivRemU";
202   case MipsISD::DivRem16:          return "MipsISD::DivRem16";
203   case MipsISD::DivRemU16:         return "MipsISD::DivRemU16";
204   case MipsISD::BuildPairF64:      return "MipsISD::BuildPairF64";
205   case MipsISD::ExtractElementF64: return "MipsISD::ExtractElementF64";
206   case MipsISD::Wrapper:           return "MipsISD::Wrapper";
207   case MipsISD::DynAlloc:          return "MipsISD::DynAlloc";
208   case MipsISD::Sync:              return "MipsISD::Sync";
209   case MipsISD::Ext:               return "MipsISD::Ext";
210   case MipsISD::Ins:               return "MipsISD::Ins";
211   case MipsISD::CIns:              return "MipsISD::CIns";
212   case MipsISD::LWL:               return "MipsISD::LWL";
213   case MipsISD::LWR:               return "MipsISD::LWR";
214   case MipsISD::SWL:               return "MipsISD::SWL";
215   case MipsISD::SWR:               return "MipsISD::SWR";
216   case MipsISD::LDL:               return "MipsISD::LDL";
217   case MipsISD::LDR:               return "MipsISD::LDR";
218   case MipsISD::SDL:               return "MipsISD::SDL";
219   case MipsISD::SDR:               return "MipsISD::SDR";
220   case MipsISD::EXTP:              return "MipsISD::EXTP";
221   case MipsISD::EXTPDP:            return "MipsISD::EXTPDP";
222   case MipsISD::EXTR_S_H:          return "MipsISD::EXTR_S_H";
223   case MipsISD::EXTR_W:            return "MipsISD::EXTR_W";
224   case MipsISD::EXTR_R_W:          return "MipsISD::EXTR_R_W";
225   case MipsISD::EXTR_RS_W:         return "MipsISD::EXTR_RS_W";
226   case MipsISD::SHILO:             return "MipsISD::SHILO";
227   case MipsISD::MTHLIP:            return "MipsISD::MTHLIP";
228   case MipsISD::MULSAQ_S_W_PH:     return "MipsISD::MULSAQ_S_W_PH";
229   case MipsISD::MAQ_S_W_PHL:       return "MipsISD::MAQ_S_W_PHL";
230   case MipsISD::MAQ_S_W_PHR:       return "MipsISD::MAQ_S_W_PHR";
231   case MipsISD::MAQ_SA_W_PHL:      return "MipsISD::MAQ_SA_W_PHL";
232   case MipsISD::MAQ_SA_W_PHR:      return "MipsISD::MAQ_SA_W_PHR";
233   case MipsISD::DPAU_H_QBL:        return "MipsISD::DPAU_H_QBL";
234   case MipsISD::DPAU_H_QBR:        return "MipsISD::DPAU_H_QBR";
235   case MipsISD::DPSU_H_QBL:        return "MipsISD::DPSU_H_QBL";
236   case MipsISD::DPSU_H_QBR:        return "MipsISD::DPSU_H_QBR";
237   case MipsISD::DPAQ_S_W_PH:       return "MipsISD::DPAQ_S_W_PH";
238   case MipsISD::DPSQ_S_W_PH:       return "MipsISD::DPSQ_S_W_PH";
239   case MipsISD::DPAQ_SA_L_W:       return "MipsISD::DPAQ_SA_L_W";
240   case MipsISD::DPSQ_SA_L_W:       return "MipsISD::DPSQ_SA_L_W";
241   case MipsISD::DPA_W_PH:          return "MipsISD::DPA_W_PH";
242   case MipsISD::DPS_W_PH:          return "MipsISD::DPS_W_PH";
243   case MipsISD::DPAQX_S_W_PH:      return "MipsISD::DPAQX_S_W_PH";
244   case MipsISD::DPAQX_SA_W_PH:     return "MipsISD::DPAQX_SA_W_PH";
245   case MipsISD::DPAX_W_PH:         return "MipsISD::DPAX_W_PH";
246   case MipsISD::DPSX_W_PH:         return "MipsISD::DPSX_W_PH";
247   case MipsISD::DPSQX_S_W_PH:      return "MipsISD::DPSQX_S_W_PH";
248   case MipsISD::DPSQX_SA_W_PH:     return "MipsISD::DPSQX_SA_W_PH";
249   case MipsISD::MULSA_W_PH:        return "MipsISD::MULSA_W_PH";
250   case MipsISD::MULT:              return "MipsISD::MULT";
251   case MipsISD::MULTU:             return "MipsISD::MULTU";
252   case MipsISD::MADD_DSP:          return "MipsISD::MADD_DSP";
253   case MipsISD::MADDU_DSP:         return "MipsISD::MADDU_DSP";
254   case MipsISD::MSUB_DSP:          return "MipsISD::MSUB_DSP";
255   case MipsISD::MSUBU_DSP:         return "MipsISD::MSUBU_DSP";
256   case MipsISD::SHLL_DSP:          return "MipsISD::SHLL_DSP";
257   case MipsISD::SHRA_DSP:          return "MipsISD::SHRA_DSP";
258   case MipsISD::SHRL_DSP:          return "MipsISD::SHRL_DSP";
259   case MipsISD::SETCC_DSP:         return "MipsISD::SETCC_DSP";
260   case MipsISD::SELECT_CC_DSP:     return "MipsISD::SELECT_CC_DSP";
261   case MipsISD::VALL_ZERO:         return "MipsISD::VALL_ZERO";
262   case MipsISD::VANY_ZERO:         return "MipsISD::VANY_ZERO";
263   case MipsISD::VALL_NONZERO:      return "MipsISD::VALL_NONZERO";
264   case MipsISD::VANY_NONZERO:      return "MipsISD::VANY_NONZERO";
265   case MipsISD::VCEQ:              return "MipsISD::VCEQ";
266   case MipsISD::VCLE_S:            return "MipsISD::VCLE_S";
267   case MipsISD::VCLE_U:            return "MipsISD::VCLE_U";
268   case MipsISD::VCLT_S:            return "MipsISD::VCLT_S";
269   case MipsISD::VCLT_U:            return "MipsISD::VCLT_U";
270   case MipsISD::VEXTRACT_SEXT_ELT: return "MipsISD::VEXTRACT_SEXT_ELT";
271   case MipsISD::VEXTRACT_ZEXT_ELT: return "MipsISD::VEXTRACT_ZEXT_ELT";
272   case MipsISD::VNOR:              return "MipsISD::VNOR";
273   case MipsISD::VSHF:              return "MipsISD::VSHF";
274   case MipsISD::SHF:               return "MipsISD::SHF";
275   case MipsISD::ILVEV:             return "MipsISD::ILVEV";
276   case MipsISD::ILVOD:             return "MipsISD::ILVOD";
277   case MipsISD::ILVL:              return "MipsISD::ILVL";
278   case MipsISD::ILVR:              return "MipsISD::ILVR";
279   case MipsISD::PCKEV:             return "MipsISD::PCKEV";
280   case MipsISD::PCKOD:             return "MipsISD::PCKOD";
281   case MipsISD::INSVE:             return "MipsISD::INSVE";
282   }
283   return nullptr;
284 }
285 
286 MipsTargetLowering::MipsTargetLowering(const MipsTargetMachine &TM,
287                                        const MipsSubtarget &STI)
288     : TargetLowering(TM), Subtarget(STI), ABI(TM.getABI()) {
289   // Mips does not have i1 type, so use i32 for
290   // setcc operations results (slt, sgt, ...).
291   setBooleanContents(ZeroOrOneBooleanContent);
292   setBooleanVectorContents(ZeroOrNegativeOneBooleanContent);
293   // The cmp.cond.fmt instruction in MIPS32r6/MIPS64r6 uses 0 and -1 like MSA
294   // does. Integer booleans still use 0 and 1.
295   if (Subtarget.hasMips32r6())
296     setBooleanContents(ZeroOrOneBooleanContent,
297                        ZeroOrNegativeOneBooleanContent);
298 
299   // Load extented operations for i1 types must be promoted
300   for (MVT VT : MVT::integer_valuetypes()) {
301     setLoadExtAction(ISD::EXTLOAD,  VT, MVT::i1,  Promote);
302     setLoadExtAction(ISD::ZEXTLOAD, VT, MVT::i1,  Promote);
303     setLoadExtAction(ISD::SEXTLOAD, VT, MVT::i1,  Promote);
304   }
305 
306   // MIPS doesn't have extending float->double load/store.  Set LoadExtAction
307   // for f32, f16
308   for (MVT VT : MVT::fp_valuetypes()) {
309     setLoadExtAction(ISD::EXTLOAD, VT, MVT::f32, Expand);
310     setLoadExtAction(ISD::EXTLOAD, VT, MVT::f16, Expand);
311   }
312 
313   // Set LoadExtAction for f16 vectors to Expand
314   for (MVT VT : MVT::fp_fixedlen_vector_valuetypes()) {
315     MVT F16VT = MVT::getVectorVT(MVT::f16, VT.getVectorNumElements());
316     if (F16VT.isValid())
317       setLoadExtAction(ISD::EXTLOAD, VT, F16VT, Expand);
318   }
319 
320   setTruncStoreAction(MVT::f32, MVT::f16, Expand);
321   setTruncStoreAction(MVT::f64, MVT::f16, Expand);
322 
323   setTruncStoreAction(MVT::f64, MVT::f32, Expand);
324 
325   // Used by legalize types to correctly generate the setcc result.
326   // Without this, every float setcc comes with a AND/OR with the result,
327   // we don't want this, since the fpcmp result goes to a flag register,
328   // which is used implicitly by brcond and select operations.
329   AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32);
330 
331   // Mips Custom Operations
332   setOperationAction(ISD::BR_JT,              MVT::Other, Expand);
333   setOperationAction(ISD::GlobalAddress,      MVT::i32,   Custom);
334   setOperationAction(ISD::BlockAddress,       MVT::i32,   Custom);
335   setOperationAction(ISD::GlobalTLSAddress,   MVT::i32,   Custom);
336   setOperationAction(ISD::JumpTable,          MVT::i32,   Custom);
337   setOperationAction(ISD::ConstantPool,       MVT::i32,   Custom);
338   setOperationAction(ISD::SELECT,             MVT::f32,   Custom);
339   setOperationAction(ISD::SELECT,             MVT::f64,   Custom);
340   setOperationAction(ISD::SELECT,             MVT::i32,   Custom);
341   setOperationAction(ISD::SETCC,              MVT::f32,   Custom);
342   setOperationAction(ISD::SETCC,              MVT::f64,   Custom);
343   setOperationAction(ISD::BRCOND,             MVT::Other, Custom);
344   setOperationAction(ISD::FCOPYSIGN,          MVT::f32,   Custom);
345   setOperationAction(ISD::FCOPYSIGN,          MVT::f64,   Custom);
346   setOperationAction(ISD::FP_TO_SINT,         MVT::i32,   Custom);
347 
348   if (!(TM.Options.NoNaNsFPMath || Subtarget.inAbs2008Mode())) {
349     setOperationAction(ISD::FABS, MVT::f32, Custom);
350     setOperationAction(ISD::FABS, MVT::f64, Custom);
351   }
352 
353   if (Subtarget.isGP64bit()) {
354     setOperationAction(ISD::GlobalAddress,      MVT::i64,   Custom);
355     setOperationAction(ISD::BlockAddress,       MVT::i64,   Custom);
356     setOperationAction(ISD::GlobalTLSAddress,   MVT::i64,   Custom);
357     setOperationAction(ISD::JumpTable,          MVT::i64,   Custom);
358     setOperationAction(ISD::ConstantPool,       MVT::i64,   Custom);
359     setOperationAction(ISD::SELECT,             MVT::i64,   Custom);
360     setOperationAction(ISD::LOAD,               MVT::i64,   Custom);
361     setOperationAction(ISD::STORE,              MVT::i64,   Custom);
362     setOperationAction(ISD::FP_TO_SINT,         MVT::i64,   Custom);
363     setOperationAction(ISD::SHL_PARTS,          MVT::i64,   Custom);
364     setOperationAction(ISD::SRA_PARTS,          MVT::i64,   Custom);
365     setOperationAction(ISD::SRL_PARTS,          MVT::i64,   Custom);
366   }
367 
368   if (!Subtarget.isGP64bit()) {
369     setOperationAction(ISD::SHL_PARTS,          MVT::i32,   Custom);
370     setOperationAction(ISD::SRA_PARTS,          MVT::i32,   Custom);
371     setOperationAction(ISD::SRL_PARTS,          MVT::i32,   Custom);
372   }
373 
374   setOperationAction(ISD::EH_DWARF_CFA,         MVT::i32,   Custom);
375   if (Subtarget.isGP64bit())
376     setOperationAction(ISD::EH_DWARF_CFA,       MVT::i64,   Custom);
377 
378   setOperationAction(ISD::SDIV, MVT::i32, Expand);
379   setOperationAction(ISD::SREM, MVT::i32, Expand);
380   setOperationAction(ISD::UDIV, MVT::i32, Expand);
381   setOperationAction(ISD::UREM, MVT::i32, Expand);
382   setOperationAction(ISD::SDIV, MVT::i64, Expand);
383   setOperationAction(ISD::SREM, MVT::i64, Expand);
384   setOperationAction(ISD::UDIV, MVT::i64, Expand);
385   setOperationAction(ISD::UREM, MVT::i64, Expand);
386 
387   // Operations not directly supported by Mips.
388   setOperationAction(ISD::BR_CC,             MVT::f32,   Expand);
389   setOperationAction(ISD::BR_CC,             MVT::f64,   Expand);
390   setOperationAction(ISD::BR_CC,             MVT::i32,   Expand);
391   setOperationAction(ISD::BR_CC,             MVT::i64,   Expand);
392   setOperationAction(ISD::SELECT_CC,         MVT::i32,   Expand);
393   setOperationAction(ISD::SELECT_CC,         MVT::i64,   Expand);
394   setOperationAction(ISD::SELECT_CC,         MVT::f32,   Expand);
395   setOperationAction(ISD::SELECT_CC,         MVT::f64,   Expand);
396   setOperationAction(ISD::UINT_TO_FP,        MVT::i32,   Expand);
397   setOperationAction(ISD::UINT_TO_FP,        MVT::i64,   Expand);
398   setOperationAction(ISD::FP_TO_UINT,        MVT::i32,   Expand);
399   setOperationAction(ISD::FP_TO_UINT,        MVT::i64,   Expand);
400   setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1,    Expand);
401   if (Subtarget.hasCnMips()) {
402     setOperationAction(ISD::CTPOP,           MVT::i32,   Legal);
403     setOperationAction(ISD::CTPOP,           MVT::i64,   Legal);
404   } else {
405     setOperationAction(ISD::CTPOP,           MVT::i32,   Expand);
406     setOperationAction(ISD::CTPOP,           MVT::i64,   Expand);
407   }
408   setOperationAction(ISD::CTTZ,              MVT::i32,   Expand);
409   setOperationAction(ISD::CTTZ,              MVT::i64,   Expand);
410   setOperationAction(ISD::ROTL,              MVT::i32,   Expand);
411   setOperationAction(ISD::ROTL,              MVT::i64,   Expand);
412   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32,  Expand);
413   setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64,  Expand);
414 
415   if (!Subtarget.hasMips32r2())
416     setOperationAction(ISD::ROTR, MVT::i32,   Expand);
417 
418   if (!Subtarget.hasMips64r2())
419     setOperationAction(ISD::ROTR, MVT::i64,   Expand);
420 
421   setOperationAction(ISD::FSIN,              MVT::f32,   Expand);
422   setOperationAction(ISD::FSIN,              MVT::f64,   Expand);
423   setOperationAction(ISD::FCOS,              MVT::f32,   Expand);
424   setOperationAction(ISD::FCOS,              MVT::f64,   Expand);
425   setOperationAction(ISD::FSINCOS,           MVT::f32,   Expand);
426   setOperationAction(ISD::FSINCOS,           MVT::f64,   Expand);
427   setOperationAction(ISD::FPOW,              MVT::f32,   Expand);
428   setOperationAction(ISD::FPOW,              MVT::f64,   Expand);
429   setOperationAction(ISD::FLOG,              MVT::f32,   Expand);
430   setOperationAction(ISD::FLOG2,             MVT::f32,   Expand);
431   setOperationAction(ISD::FLOG10,            MVT::f32,   Expand);
432   setOperationAction(ISD::FEXP,              MVT::f32,   Expand);
433   setOperationAction(ISD::FMA,               MVT::f32,   Expand);
434   setOperationAction(ISD::FMA,               MVT::f64,   Expand);
435   setOperationAction(ISD::FREM,              MVT::f32,   Expand);
436   setOperationAction(ISD::FREM,              MVT::f64,   Expand);
437 
438   // Lower f16 conversion operations into library calls
439   setOperationAction(ISD::FP16_TO_FP,        MVT::f32,   Expand);
440   setOperationAction(ISD::FP_TO_FP16,        MVT::f32,   Expand);
441   setOperationAction(ISD::FP16_TO_FP,        MVT::f64,   Expand);
442   setOperationAction(ISD::FP_TO_FP16,        MVT::f64,   Expand);
443 
444   setOperationAction(ISD::EH_RETURN, MVT::Other, Custom);
445 
446   setOperationAction(ISD::VASTART,           MVT::Other, Custom);
447   setOperationAction(ISD::VAARG,             MVT::Other, Custom);
448   setOperationAction(ISD::VACOPY,            MVT::Other, Expand);
449   setOperationAction(ISD::VAEND,             MVT::Other, Expand);
450 
451   // Use the default for now
452   setOperationAction(ISD::STACKSAVE,         MVT::Other, Expand);
453   setOperationAction(ISD::STACKRESTORE,      MVT::Other, Expand);
454 
455   if (!Subtarget.isGP64bit()) {
456     setOperationAction(ISD::ATOMIC_LOAD,     MVT::i64,   Expand);
457     setOperationAction(ISD::ATOMIC_STORE,    MVT::i64,   Expand);
458   }
459 
460   if (!Subtarget.hasMips32r2()) {
461     setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8,  Expand);
462     setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16, Expand);
463   }
464 
465   // MIPS16 lacks MIPS32's clz and clo instructions.
466   if (!Subtarget.hasMips32() || Subtarget.inMips16Mode())
467     setOperationAction(ISD::CTLZ, MVT::i32, Expand);
468   if (!Subtarget.hasMips64())
469     setOperationAction(ISD::CTLZ, MVT::i64, Expand);
470 
471   if (!Subtarget.hasMips32r2())
472     setOperationAction(ISD::BSWAP, MVT::i32, Expand);
473   if (!Subtarget.hasMips64r2())
474     setOperationAction(ISD::BSWAP, MVT::i64, Expand);
475 
476   if (Subtarget.isGP64bit()) {
477     setLoadExtAction(ISD::SEXTLOAD, MVT::i64, MVT::i32, Custom);
478     setLoadExtAction(ISD::ZEXTLOAD, MVT::i64, MVT::i32, Custom);
479     setLoadExtAction(ISD::EXTLOAD, MVT::i64, MVT::i32, Custom);
480     setTruncStoreAction(MVT::i64, MVT::i32, Custom);
481   }
482 
483   setOperationAction(ISD::TRAP, MVT::Other, Legal);
484 
485   setTargetDAGCombine({ISD::SDIVREM, ISD::UDIVREM, ISD::SELECT, ISD::AND,
486                        ISD::OR, ISD::ADD, ISD::SUB, ISD::AssertZext, ISD::SHL});
487 
488   if (ABI.IsO32()) {
489     // These libcalls are not available in 32-bit.
490     setLibcallName(RTLIB::SHL_I128, nullptr);
491     setLibcallName(RTLIB::SRL_I128, nullptr);
492     setLibcallName(RTLIB::SRA_I128, nullptr);
493     setLibcallName(RTLIB::MUL_I128, nullptr);
494     setLibcallName(RTLIB::MULO_I64, nullptr);
495     setLibcallName(RTLIB::MULO_I128, nullptr);
496   }
497 
498   setMinFunctionAlignment(Subtarget.isGP64bit() ? Align(8) : Align(4));
499 
500   // The arguments on the stack are defined in terms of 4-byte slots on O32
501   // and 8-byte slots on N32/N64.
502   setMinStackArgumentAlignment((ABI.IsN32() || ABI.IsN64()) ? Align(8)
503                                                             : Align(4));
504 
505   setStackPointerRegisterToSaveRestore(ABI.IsN64() ? Mips::SP_64 : Mips::SP);
506 
507   MaxStoresPerMemcpy = 16;
508 
509   isMicroMips = Subtarget.inMicroMipsMode();
510 }
511 
512 const MipsTargetLowering *
513 MipsTargetLowering::create(const MipsTargetMachine &TM,
514                            const MipsSubtarget &STI) {
515   if (STI.inMips16Mode())
516     return createMips16TargetLowering(TM, STI);
517 
518   return createMipsSETargetLowering(TM, STI);
519 }
520 
521 // Create a fast isel object.
522 FastISel *
523 MipsTargetLowering::createFastISel(FunctionLoweringInfo &funcInfo,
524                                   const TargetLibraryInfo *libInfo) const {
525   const MipsTargetMachine &TM =
526       static_cast<const MipsTargetMachine &>(funcInfo.MF->getTarget());
527 
528   // We support only the standard encoding [MIPS32,MIPS32R5] ISAs.
529   bool UseFastISel = TM.Options.EnableFastISel && Subtarget.hasMips32() &&
530                      !Subtarget.hasMips32r6() && !Subtarget.inMips16Mode() &&
531                      !Subtarget.inMicroMipsMode();
532 
533   // Disable if either of the following is true:
534   // We do not generate PIC, the ABI is not O32, XGOT is being used.
535   if (!TM.isPositionIndependent() || !TM.getABI().IsO32() ||
536       Subtarget.useXGOT())
537     UseFastISel = false;
538 
539   return UseFastISel ? Mips::createFastISel(funcInfo, libInfo) : nullptr;
540 }
541 
542 EVT MipsTargetLowering::getSetCCResultType(const DataLayout &, LLVMContext &,
543                                            EVT VT) const {
544   if (!VT.isVector())
545     return MVT::i32;
546   return VT.changeVectorElementTypeToInteger();
547 }
548 
549 static SDValue performDivRemCombine(SDNode *N, SelectionDAG &DAG,
550                                     TargetLowering::DAGCombinerInfo &DCI,
551                                     const MipsSubtarget &Subtarget) {
552   if (DCI.isBeforeLegalizeOps())
553     return SDValue();
554 
555   EVT Ty = N->getValueType(0);
556   unsigned LO = (Ty == MVT::i32) ? Mips::LO0 : Mips::LO0_64;
557   unsigned HI = (Ty == MVT::i32) ? Mips::HI0 : Mips::HI0_64;
558   unsigned Opc = N->getOpcode() == ISD::SDIVREM ? MipsISD::DivRem16 :
559                                                   MipsISD::DivRemU16;
560   SDLoc DL(N);
561 
562   SDValue DivRem = DAG.getNode(Opc, DL, MVT::Glue,
563                                N->getOperand(0), N->getOperand(1));
564   SDValue InChain = DAG.getEntryNode();
565   SDValue InGlue = DivRem;
566 
567   // insert MFLO
568   if (N->hasAnyUseOfValue(0)) {
569     SDValue CopyFromLo = DAG.getCopyFromReg(InChain, DL, LO, Ty,
570                                             InGlue);
571     DAG.ReplaceAllUsesOfValueWith(SDValue(N, 0), CopyFromLo);
572     InChain = CopyFromLo.getValue(1);
573     InGlue = CopyFromLo.getValue(2);
574   }
575 
576   // insert MFHI
577   if (N->hasAnyUseOfValue(1)) {
578     SDValue CopyFromHi = DAG.getCopyFromReg(InChain, DL,
579                                             HI, Ty, InGlue);
580     DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), CopyFromHi);
581   }
582 
583   return SDValue();
584 }
585 
586 static Mips::CondCode condCodeToFCC(ISD::CondCode CC) {
587   switch (CC) {
588   default: llvm_unreachable("Unknown fp condition code!");
589   case ISD::SETEQ:
590   case ISD::SETOEQ: return Mips::FCOND_OEQ;
591   case ISD::SETUNE: return Mips::FCOND_UNE;
592   case ISD::SETLT:
593   case ISD::SETOLT: return Mips::FCOND_OLT;
594   case ISD::SETGT:
595   case ISD::SETOGT: return Mips::FCOND_OGT;
596   case ISD::SETLE:
597   case ISD::SETOLE: return Mips::FCOND_OLE;
598   case ISD::SETGE:
599   case ISD::SETOGE: return Mips::FCOND_OGE;
600   case ISD::SETULT: return Mips::FCOND_ULT;
601   case ISD::SETULE: return Mips::FCOND_ULE;
602   case ISD::SETUGT: return Mips::FCOND_UGT;
603   case ISD::SETUGE: return Mips::FCOND_UGE;
604   case ISD::SETUO:  return Mips::FCOND_UN;
605   case ISD::SETO:   return Mips::FCOND_OR;
606   case ISD::SETNE:
607   case ISD::SETONE: return Mips::FCOND_ONE;
608   case ISD::SETUEQ: return Mips::FCOND_UEQ;
609   }
610 }
611 
612 /// This function returns true if the floating point conditional branches and
613 /// conditional moves which use condition code CC should be inverted.
614 static bool invertFPCondCodeUser(Mips::CondCode CC) {
615   if (CC >= Mips::FCOND_F && CC <= Mips::FCOND_NGT)
616     return false;
617 
618   assert((CC >= Mips::FCOND_T && CC <= Mips::FCOND_GT) &&
619          "Illegal Condition Code");
620 
621   return true;
622 }
623 
624 // Creates and returns an FPCmp node from a setcc node.
625 // Returns Op if setcc is not a floating point comparison.
626 static SDValue createFPCmp(SelectionDAG &DAG, const SDValue &Op) {
627   // must be a SETCC node
628   if (Op.getOpcode() != ISD::SETCC)
629     return Op;
630 
631   SDValue LHS = Op.getOperand(0);
632 
633   if (!LHS.getValueType().isFloatingPoint())
634     return Op;
635 
636   SDValue RHS = Op.getOperand(1);
637   SDLoc DL(Op);
638 
639   // Assume the 3rd operand is a CondCodeSDNode. Add code to check the type of
640   // node if necessary.
641   ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
642 
643   return DAG.getNode(MipsISD::FPCmp, DL, MVT::Glue, LHS, RHS,
644                      DAG.getConstant(condCodeToFCC(CC), DL, MVT::i32));
645 }
646 
647 // Creates and returns a CMovFPT/F node.
648 static SDValue createCMovFP(SelectionDAG &DAG, SDValue Cond, SDValue True,
649                             SDValue False, const SDLoc &DL) {
650   ConstantSDNode *CC = cast<ConstantSDNode>(Cond.getOperand(2));
651   bool invert = invertFPCondCodeUser((Mips::CondCode)CC->getSExtValue());
652   SDValue FCC0 = DAG.getRegister(Mips::FCC0, MVT::i32);
653 
654   return DAG.getNode((invert ? MipsISD::CMovFP_F : MipsISD::CMovFP_T), DL,
655                      True.getValueType(), True, FCC0, False, Cond);
656 }
657 
658 static SDValue performSELECTCombine(SDNode *N, SelectionDAG &DAG,
659                                     TargetLowering::DAGCombinerInfo &DCI,
660                                     const MipsSubtarget &Subtarget) {
661   if (DCI.isBeforeLegalizeOps())
662     return SDValue();
663 
664   SDValue SetCC = N->getOperand(0);
665 
666   if ((SetCC.getOpcode() != ISD::SETCC) ||
667       !SetCC.getOperand(0).getValueType().isInteger())
668     return SDValue();
669 
670   SDValue False = N->getOperand(2);
671   EVT FalseTy = False.getValueType();
672 
673   if (!FalseTy.isInteger())
674     return SDValue();
675 
676   ConstantSDNode *FalseC = dyn_cast<ConstantSDNode>(False);
677 
678   // If the RHS (False) is 0, we swap the order of the operands
679   // of ISD::SELECT (obviously also inverting the condition) so that we can
680   // take advantage of conditional moves using the $0 register.
681   // Example:
682   //   return (a != 0) ? x : 0;
683   //     load $reg, x
684   //     movz $reg, $0, a
685   if (!FalseC)
686     return SDValue();
687 
688   const SDLoc DL(N);
689 
690   if (!FalseC->getZExtValue()) {
691     ISD::CondCode CC = cast<CondCodeSDNode>(SetCC.getOperand(2))->get();
692     SDValue True = N->getOperand(1);
693 
694     SetCC = DAG.getSetCC(DL, SetCC.getValueType(), SetCC.getOperand(0),
695                          SetCC.getOperand(1),
696                          ISD::getSetCCInverse(CC, SetCC.getValueType()));
697 
698     return DAG.getNode(ISD::SELECT, DL, FalseTy, SetCC, False, True);
699   }
700 
701   // If both operands are integer constants there's a possibility that we
702   // can do some interesting optimizations.
703   SDValue True = N->getOperand(1);
704   ConstantSDNode *TrueC = dyn_cast<ConstantSDNode>(True);
705 
706   if (!TrueC || !True.getValueType().isInteger())
707     return SDValue();
708 
709   // We'll also ignore MVT::i64 operands as this optimizations proves
710   // to be ineffective because of the required sign extensions as the result
711   // of a SETCC operator is always MVT::i32 for non-vector types.
712   if (True.getValueType() == MVT::i64)
713     return SDValue();
714 
715   int64_t Diff = TrueC->getSExtValue() - FalseC->getSExtValue();
716 
717   // 1)  (a < x) ? y : y-1
718   //  slti $reg1, a, x
719   //  addiu $reg2, $reg1, y-1
720   if (Diff == 1)
721     return DAG.getNode(ISD::ADD, DL, SetCC.getValueType(), SetCC, False);
722 
723   // 2)  (a < x) ? y-1 : y
724   //  slti $reg1, a, x
725   //  xor $reg1, $reg1, 1
726   //  addiu $reg2, $reg1, y-1
727   if (Diff == -1) {
728     ISD::CondCode CC = cast<CondCodeSDNode>(SetCC.getOperand(2))->get();
729     SetCC = DAG.getSetCC(DL, SetCC.getValueType(), SetCC.getOperand(0),
730                          SetCC.getOperand(1),
731                          ISD::getSetCCInverse(CC, SetCC.getValueType()));
732     return DAG.getNode(ISD::ADD, DL, SetCC.getValueType(), SetCC, True);
733   }
734 
735   // Could not optimize.
736   return SDValue();
737 }
738 
739 static SDValue performCMovFPCombine(SDNode *N, SelectionDAG &DAG,
740                                     TargetLowering::DAGCombinerInfo &DCI,
741                                     const MipsSubtarget &Subtarget) {
742   if (DCI.isBeforeLegalizeOps())
743     return SDValue();
744 
745   SDValue ValueIfTrue = N->getOperand(0), ValueIfFalse = N->getOperand(2);
746 
747   ConstantSDNode *FalseC = dyn_cast<ConstantSDNode>(ValueIfFalse);
748   if (!FalseC || FalseC->getZExtValue())
749     return SDValue();
750 
751   // Since RHS (False) is 0, we swap the order of the True/False operands
752   // (obviously also inverting the condition) so that we can
753   // take advantage of conditional moves using the $0 register.
754   // Example:
755   //   return (a != 0) ? x : 0;
756   //     load $reg, x
757   //     movz $reg, $0, a
758   unsigned Opc = (N->getOpcode() == MipsISD::CMovFP_T) ? MipsISD::CMovFP_F :
759                                                          MipsISD::CMovFP_T;
760 
761   SDValue FCC = N->getOperand(1), Glue = N->getOperand(3);
762   return DAG.getNode(Opc, SDLoc(N), ValueIfFalse.getValueType(),
763                      ValueIfFalse, FCC, ValueIfTrue, Glue);
764 }
765 
766 static SDValue performANDCombine(SDNode *N, SelectionDAG &DAG,
767                                  TargetLowering::DAGCombinerInfo &DCI,
768                                  const MipsSubtarget &Subtarget) {
769   if (DCI.isBeforeLegalizeOps() || !Subtarget.hasExtractInsert())
770     return SDValue();
771 
772   SDValue FirstOperand = N->getOperand(0);
773   unsigned FirstOperandOpc = FirstOperand.getOpcode();
774   SDValue Mask = N->getOperand(1);
775   EVT ValTy = N->getValueType(0);
776   SDLoc DL(N);
777 
778   uint64_t Pos = 0;
779   unsigned SMPos, SMSize;
780   ConstantSDNode *CN;
781   SDValue NewOperand;
782   unsigned Opc;
783 
784   // Op's second operand must be a shifted mask.
785   if (!(CN = dyn_cast<ConstantSDNode>(Mask)) ||
786       !isShiftedMask_64(CN->getZExtValue(), SMPos, SMSize))
787     return SDValue();
788 
789   if (FirstOperandOpc == ISD::SRA || FirstOperandOpc == ISD::SRL) {
790     // Pattern match EXT.
791     //  $dst = and ((sra or srl) $src , pos), (2**size - 1)
792     //  => ext $dst, $src, pos, size
793 
794     // The second operand of the shift must be an immediate.
795     if (!(CN = dyn_cast<ConstantSDNode>(FirstOperand.getOperand(1))))
796       return SDValue();
797 
798     Pos = CN->getZExtValue();
799 
800     // Return if the shifted mask does not start at bit 0 or the sum of its size
801     // and Pos exceeds the word's size.
802     if (SMPos != 0 || Pos + SMSize > ValTy.getSizeInBits())
803       return SDValue();
804 
805     Opc = MipsISD::Ext;
806     NewOperand = FirstOperand.getOperand(0);
807   } else if (FirstOperandOpc == ISD::SHL && Subtarget.hasCnMips()) {
808     // Pattern match CINS.
809     //  $dst = and (shl $src , pos), mask
810     //  => cins $dst, $src, pos, size
811     // mask is a shifted mask with consecutive 1's, pos = shift amount,
812     // size = population count.
813 
814     // The second operand of the shift must be an immediate.
815     if (!(CN = dyn_cast<ConstantSDNode>(FirstOperand.getOperand(1))))
816       return SDValue();
817 
818     Pos = CN->getZExtValue();
819 
820     if (SMPos != Pos || Pos >= ValTy.getSizeInBits() || SMSize >= 32 ||
821         Pos + SMSize > ValTy.getSizeInBits())
822       return SDValue();
823 
824     NewOperand = FirstOperand.getOperand(0);
825     // SMSize is 'location' (position) in this case, not size.
826     SMSize--;
827     Opc = MipsISD::CIns;
828   } else {
829     // Pattern match EXT.
830     //  $dst = and $src, (2**size - 1) , if size > 16
831     //  => ext $dst, $src, pos, size , pos = 0
832 
833     // If the mask is <= 0xffff, andi can be used instead.
834     if (CN->getZExtValue() <= 0xffff)
835       return SDValue();
836 
837     // Return if the mask doesn't start at position 0.
838     if (SMPos)
839       return SDValue();
840 
841     Opc = MipsISD::Ext;
842     NewOperand = FirstOperand;
843   }
844   return DAG.getNode(Opc, DL, ValTy, NewOperand,
845                      DAG.getConstant(Pos, DL, MVT::i32),
846                      DAG.getConstant(SMSize, DL, MVT::i32));
847 }
848 
849 static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
850                                 TargetLowering::DAGCombinerInfo &DCI,
851                                 const MipsSubtarget &Subtarget) {
852   // Pattern match INS.
853   //  $dst = or (and $src1 , mask0), (and (shl $src, pos), mask1),
854   //  where mask1 = (2**size - 1) << pos, mask0 = ~mask1
855   //  => ins $dst, $src, size, pos, $src1
856   if (DCI.isBeforeLegalizeOps() || !Subtarget.hasExtractInsert())
857     return SDValue();
858 
859   SDValue And0 = N->getOperand(0), And1 = N->getOperand(1);
860   unsigned SMPos0, SMSize0, SMPos1, SMSize1;
861   ConstantSDNode *CN, *CN1;
862 
863   // See if Op's first operand matches (and $src1 , mask0).
864   if (And0.getOpcode() != ISD::AND)
865     return SDValue();
866 
867   if (!(CN = dyn_cast<ConstantSDNode>(And0.getOperand(1))) ||
868       !isShiftedMask_64(~CN->getSExtValue(), SMPos0, SMSize0))
869     return SDValue();
870 
871   // See if Op's second operand matches (and (shl $src, pos), mask1).
872   if (And1.getOpcode() == ISD::AND &&
873       And1.getOperand(0).getOpcode() == ISD::SHL) {
874 
875     if (!(CN = dyn_cast<ConstantSDNode>(And1.getOperand(1))) ||
876         !isShiftedMask_64(CN->getZExtValue(), SMPos1, SMSize1))
877       return SDValue();
878 
879     // The shift masks must have the same position and size.
880     if (SMPos0 != SMPos1 || SMSize0 != SMSize1)
881       return SDValue();
882 
883     SDValue Shl = And1.getOperand(0);
884 
885     if (!(CN = dyn_cast<ConstantSDNode>(Shl.getOperand(1))))
886       return SDValue();
887 
888     unsigned Shamt = CN->getZExtValue();
889 
890     // Return if the shift amount and the first bit position of mask are not the
891     // same.
892     EVT ValTy = N->getValueType(0);
893     if ((Shamt != SMPos0) || (SMPos0 + SMSize0 > ValTy.getSizeInBits()))
894       return SDValue();
895 
896     SDLoc DL(N);
897     return DAG.getNode(MipsISD::Ins, DL, ValTy, Shl.getOperand(0),
898                        DAG.getConstant(SMPos0, DL, MVT::i32),
899                        DAG.getConstant(SMSize0, DL, MVT::i32),
900                        And0.getOperand(0));
901   } else {
902     // Pattern match DINS.
903     //  $dst = or (and $src, mask0), mask1
904     //  where mask0 = ((1 << SMSize0) -1) << SMPos0
905     //  => dins $dst, $src, pos, size
906     if (~CN->getSExtValue() == ((((int64_t)1 << SMSize0) - 1) << SMPos0) &&
907         ((SMSize0 + SMPos0 <= 64 && Subtarget.hasMips64r2()) ||
908          (SMSize0 + SMPos0 <= 32))) {
909       // Check if AND instruction has constant as argument
910       bool isConstCase = And1.getOpcode() != ISD::AND;
911       if (And1.getOpcode() == ISD::AND) {
912         if (!(CN1 = dyn_cast<ConstantSDNode>(And1->getOperand(1))))
913           return SDValue();
914       } else {
915         if (!(CN1 = dyn_cast<ConstantSDNode>(N->getOperand(1))))
916           return SDValue();
917       }
918       // Don't generate INS if constant OR operand doesn't fit into bits
919       // cleared by constant AND operand.
920       if (CN->getSExtValue() & CN1->getSExtValue())
921         return SDValue();
922 
923       SDLoc DL(N);
924       EVT ValTy = N->getOperand(0)->getValueType(0);
925       SDValue Const1;
926       SDValue SrlX;
927       if (!isConstCase) {
928         Const1 = DAG.getConstant(SMPos0, DL, MVT::i32);
929         SrlX = DAG.getNode(ISD::SRL, DL, And1->getValueType(0), And1, Const1);
930       }
931       return DAG.getNode(
932           MipsISD::Ins, DL, N->getValueType(0),
933           isConstCase
934               ? DAG.getConstant(CN1->getSExtValue() >> SMPos0, DL, ValTy)
935               : SrlX,
936           DAG.getConstant(SMPos0, DL, MVT::i32),
937           DAG.getConstant(ValTy.getSizeInBits() / 8 < 8 ? SMSize0 & 31
938                                                         : SMSize0,
939                           DL, MVT::i32),
940           And0->getOperand(0));
941 
942     }
943     return SDValue();
944   }
945 }
946 
947 static SDValue performMADD_MSUBCombine(SDNode *ROOTNode, SelectionDAG &CurDAG,
948                                        const MipsSubtarget &Subtarget) {
949   // ROOTNode must have a multiplication as an operand for the match to be
950   // successful.
951   if (ROOTNode->getOperand(0).getOpcode() != ISD::MUL &&
952       ROOTNode->getOperand(1).getOpcode() != ISD::MUL)
953     return SDValue();
954 
955   // We don't handle vector types here.
956   if (ROOTNode->getValueType(0).isVector())
957     return SDValue();
958 
959   // For MIPS64, madd / msub instructions are inefficent to use with 64 bit
960   // arithmetic. E.g.
961   // (add (mul a b) c) =>
962   //   let res = (madd (mthi (drotr c 32))x(mtlo c) a b) in
963   //   MIPS64:   (or (dsll (mfhi res) 32) (dsrl (dsll (mflo res) 32) 32)
964   //   or
965   //   MIPS64R2: (dins (mflo res) (mfhi res) 32 32)
966   //
967   // The overhead of setting up the Hi/Lo registers and reassembling the
968   // result makes this a dubious optimzation for MIPS64. The core of the
969   // problem is that Hi/Lo contain the upper and lower 32 bits of the
970   // operand and result.
971   //
972   // It requires a chain of 4 add/mul for MIPS64R2 to get better code
973   // density than doing it naively, 5 for MIPS64. Additionally, using
974   // madd/msub on MIPS64 requires the operands actually be 32 bit sign
975   // extended operands, not true 64 bit values.
976   //
977   // FIXME: For the moment, disable this completely for MIPS64.
978   if (Subtarget.hasMips64())
979     return SDValue();
980 
981   SDValue Mult = ROOTNode->getOperand(0).getOpcode() == ISD::MUL
982                      ? ROOTNode->getOperand(0)
983                      : ROOTNode->getOperand(1);
984 
985   SDValue AddOperand = ROOTNode->getOperand(0).getOpcode() == ISD::MUL
986                      ? ROOTNode->getOperand(1)
987                      : ROOTNode->getOperand(0);
988 
989   // Transform this to a MADD only if the user of this node is the add.
990   // If there are other users of the mul, this function returns here.
991   if (!Mult.hasOneUse())
992     return SDValue();
993 
994   // maddu and madd are unusual instructions in that on MIPS64 bits 63..31
995   // must be in canonical form, i.e. sign extended. For MIPS32, the operands
996   // of the multiply must have 32 or more sign bits, otherwise we cannot
997   // perform this optimization. We have to check this here as we're performing
998   // this optimization pre-legalization.
999   SDValue MultLHS = Mult->getOperand(0);
1000   SDValue MultRHS = Mult->getOperand(1);
1001 
1002   bool IsSigned = MultLHS->getOpcode() == ISD::SIGN_EXTEND &&
1003                   MultRHS->getOpcode() == ISD::SIGN_EXTEND;
1004   bool IsUnsigned = MultLHS->getOpcode() == ISD::ZERO_EXTEND &&
1005                     MultRHS->getOpcode() == ISD::ZERO_EXTEND;
1006 
1007   if (!IsSigned && !IsUnsigned)
1008     return SDValue();
1009 
1010   // Initialize accumulator.
1011   SDLoc DL(ROOTNode);
1012   SDValue TopHalf;
1013   SDValue BottomHalf;
1014   BottomHalf = CurDAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, AddOperand,
1015                               CurDAG.getIntPtrConstant(0, DL));
1016 
1017   TopHalf = CurDAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i32, AddOperand,
1018                            CurDAG.getIntPtrConstant(1, DL));
1019   SDValue ACCIn = CurDAG.getNode(MipsISD::MTLOHI, DL, MVT::Untyped,
1020                                   BottomHalf,
1021                                   TopHalf);
1022 
1023   // Create MipsMAdd(u) / MipsMSub(u) node.
1024   bool IsAdd = ROOTNode->getOpcode() == ISD::ADD;
1025   unsigned Opcode = IsAdd ? (IsUnsigned ? MipsISD::MAddu : MipsISD::MAdd)
1026                           : (IsUnsigned ? MipsISD::MSubu : MipsISD::MSub);
1027   SDValue MAddOps[3] = {
1028       CurDAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Mult->getOperand(0)),
1029       CurDAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Mult->getOperand(1)), ACCIn};
1030   EVT VTs[2] = {MVT::i32, MVT::i32};
1031   SDValue MAdd = CurDAG.getNode(Opcode, DL, VTs, MAddOps);
1032 
1033   SDValue ResLo = CurDAG.getNode(MipsISD::MFLO, DL, MVT::i32, MAdd);
1034   SDValue ResHi = CurDAG.getNode(MipsISD::MFHI, DL, MVT::i32, MAdd);
1035   SDValue Combined =
1036       CurDAG.getNode(ISD::BUILD_PAIR, DL, MVT::i64, ResLo, ResHi);
1037   return Combined;
1038 }
1039 
1040 static SDValue performSUBCombine(SDNode *N, SelectionDAG &DAG,
1041                                  TargetLowering::DAGCombinerInfo &DCI,
1042                                  const MipsSubtarget &Subtarget) {
1043   // (sub v0 (mul v1, v2)) => (msub v1, v2, v0)
1044   if (DCI.isBeforeLegalizeOps()) {
1045     if (Subtarget.hasMips32() && !Subtarget.hasMips32r6() &&
1046         !Subtarget.inMips16Mode() && N->getValueType(0) == MVT::i64)
1047       return performMADD_MSUBCombine(N, DAG, Subtarget);
1048 
1049     return SDValue();
1050   }
1051 
1052   return SDValue();
1053 }
1054 
1055 static SDValue performADDCombine(SDNode *N, SelectionDAG &DAG,
1056                                  TargetLowering::DAGCombinerInfo &DCI,
1057                                  const MipsSubtarget &Subtarget) {
1058   // (add v0 (mul v1, v2)) => (madd v1, v2, v0)
1059   if (DCI.isBeforeLegalizeOps()) {
1060     if (Subtarget.hasMips32() && !Subtarget.hasMips32r6() &&
1061         !Subtarget.inMips16Mode() && N->getValueType(0) == MVT::i64)
1062       return performMADD_MSUBCombine(N, DAG, Subtarget);
1063 
1064     return SDValue();
1065   }
1066 
1067   // (add v0, (add v1, abs_lo(tjt))) => (add (add v0, v1), abs_lo(tjt))
1068   SDValue Add = N->getOperand(1);
1069 
1070   if (Add.getOpcode() != ISD::ADD)
1071     return SDValue();
1072 
1073   SDValue Lo = Add.getOperand(1);
1074 
1075   if ((Lo.getOpcode() != MipsISD::Lo) ||
1076       (Lo.getOperand(0).getOpcode() != ISD::TargetJumpTable))
1077     return SDValue();
1078 
1079   EVT ValTy = N->getValueType(0);
1080   SDLoc DL(N);
1081 
1082   SDValue Add1 = DAG.getNode(ISD::ADD, DL, ValTy, N->getOperand(0),
1083                              Add.getOperand(0));
1084   return DAG.getNode(ISD::ADD, DL, ValTy, Add1, Lo);
1085 }
1086 
1087 static SDValue performSHLCombine(SDNode *N, SelectionDAG &DAG,
1088                                  TargetLowering::DAGCombinerInfo &DCI,
1089                                  const MipsSubtarget &Subtarget) {
1090   // Pattern match CINS.
1091   //  $dst = shl (and $src , imm), pos
1092   //  => cins $dst, $src, pos, size
1093 
1094   if (DCI.isBeforeLegalizeOps() || !Subtarget.hasCnMips())
1095     return SDValue();
1096 
1097   SDValue FirstOperand = N->getOperand(0);
1098   unsigned FirstOperandOpc = FirstOperand.getOpcode();
1099   SDValue SecondOperand = N->getOperand(1);
1100   EVT ValTy = N->getValueType(0);
1101   SDLoc DL(N);
1102 
1103   uint64_t Pos = 0;
1104   unsigned SMPos, SMSize;
1105   ConstantSDNode *CN;
1106   SDValue NewOperand;
1107 
1108   // The second operand of the shift must be an immediate.
1109   if (!(CN = dyn_cast<ConstantSDNode>(SecondOperand)))
1110     return SDValue();
1111 
1112   Pos = CN->getZExtValue();
1113 
1114   if (Pos >= ValTy.getSizeInBits())
1115     return SDValue();
1116 
1117   if (FirstOperandOpc != ISD::AND)
1118     return SDValue();
1119 
1120   // AND's second operand must be a shifted mask.
1121   if (!(CN = dyn_cast<ConstantSDNode>(FirstOperand.getOperand(1))) ||
1122       !isShiftedMask_64(CN->getZExtValue(), SMPos, SMSize))
1123     return SDValue();
1124 
1125   // Return if the shifted mask does not start at bit 0 or the sum of its size
1126   // and Pos exceeds the word's size.
1127   if (SMPos != 0 || SMSize > 32 || Pos + SMSize > ValTy.getSizeInBits())
1128     return SDValue();
1129 
1130   NewOperand = FirstOperand.getOperand(0);
1131   // SMSize is 'location' (position) in this case, not size.
1132   SMSize--;
1133 
1134   return DAG.getNode(MipsISD::CIns, DL, ValTy, NewOperand,
1135                      DAG.getConstant(Pos, DL, MVT::i32),
1136                      DAG.getConstant(SMSize, DL, MVT::i32));
1137 }
1138 
1139 SDValue  MipsTargetLowering::PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI)
1140   const {
1141   SelectionDAG &DAG = DCI.DAG;
1142   unsigned Opc = N->getOpcode();
1143 
1144   switch (Opc) {
1145   default: break;
1146   case ISD::SDIVREM:
1147   case ISD::UDIVREM:
1148     return performDivRemCombine(N, DAG, DCI, Subtarget);
1149   case ISD::SELECT:
1150     return performSELECTCombine(N, DAG, DCI, Subtarget);
1151   case MipsISD::CMovFP_F:
1152   case MipsISD::CMovFP_T:
1153     return performCMovFPCombine(N, DAG, DCI, Subtarget);
1154   case ISD::AND:
1155     return performANDCombine(N, DAG, DCI, Subtarget);
1156   case ISD::OR:
1157     return performORCombine(N, DAG, DCI, Subtarget);
1158   case ISD::ADD:
1159     return performADDCombine(N, DAG, DCI, Subtarget);
1160   case ISD::SHL:
1161     return performSHLCombine(N, DAG, DCI, Subtarget);
1162   case ISD::SUB:
1163     return performSUBCombine(N, DAG, DCI, Subtarget);
1164   }
1165 
1166   return SDValue();
1167 }
1168 
1169 bool MipsTargetLowering::isCheapToSpeculateCttz() const {
1170   return Subtarget.hasMips32();
1171 }
1172 
1173 bool MipsTargetLowering::isCheapToSpeculateCtlz() const {
1174   return Subtarget.hasMips32();
1175 }
1176 
1177 bool MipsTargetLowering::hasBitTest(SDValue X, SDValue Y) const {
1178   // We can use ANDI+SLTIU as a bit test. Y contains the bit position.
1179   // For MIPSR2 or later, we may be able to use the `ext` instruction or its'
1180   // double-word variants.
1181   if (auto *C = dyn_cast<ConstantSDNode>(Y))
1182     return C->getAPIntValue().ule(15);
1183 
1184   return false;
1185 }
1186 
1187 bool MipsTargetLowering::shouldFoldConstantShiftPairToMask(
1188     const SDNode *N, CombineLevel Level) const {
1189   if (N->getOperand(0).getValueType().isVector())
1190     return false;
1191   return true;
1192 }
1193 
1194 void
1195 MipsTargetLowering::ReplaceNodeResults(SDNode *N,
1196                                        SmallVectorImpl<SDValue> &Results,
1197                                        SelectionDAG &DAG) const {
1198   return LowerOperationWrapper(N, Results, DAG);
1199 }
1200 
1201 SDValue MipsTargetLowering::
1202 LowerOperation(SDValue Op, SelectionDAG &DAG) const
1203 {
1204   switch (Op.getOpcode())
1205   {
1206   case ISD::BRCOND:             return lowerBRCOND(Op, DAG);
1207   case ISD::ConstantPool:       return lowerConstantPool(Op, DAG);
1208   case ISD::GlobalAddress:      return lowerGlobalAddress(Op, DAG);
1209   case ISD::BlockAddress:       return lowerBlockAddress(Op, DAG);
1210   case ISD::GlobalTLSAddress:   return lowerGlobalTLSAddress(Op, DAG);
1211   case ISD::JumpTable:          return lowerJumpTable(Op, DAG);
1212   case ISD::SELECT:             return lowerSELECT(Op, DAG);
1213   case ISD::SETCC:              return lowerSETCC(Op, DAG);
1214   case ISD::VASTART:            return lowerVASTART(Op, DAG);
1215   case ISD::VAARG:              return lowerVAARG(Op, DAG);
1216   case ISD::FCOPYSIGN:          return lowerFCOPYSIGN(Op, DAG);
1217   case ISD::FABS:               return lowerFABS(Op, DAG);
1218   case ISD::FRAMEADDR:          return lowerFRAMEADDR(Op, DAG);
1219   case ISD::RETURNADDR:         return lowerRETURNADDR(Op, DAG);
1220   case ISD::EH_RETURN:          return lowerEH_RETURN(Op, DAG);
1221   case ISD::ATOMIC_FENCE:       return lowerATOMIC_FENCE(Op, DAG);
1222   case ISD::SHL_PARTS:          return lowerShiftLeftParts(Op, DAG);
1223   case ISD::SRA_PARTS:          return lowerShiftRightParts(Op, DAG, true);
1224   case ISD::SRL_PARTS:          return lowerShiftRightParts(Op, DAG, false);
1225   case ISD::LOAD:               return lowerLOAD(Op, DAG);
1226   case ISD::STORE:              return lowerSTORE(Op, DAG);
1227   case ISD::EH_DWARF_CFA:       return lowerEH_DWARF_CFA(Op, DAG);
1228   case ISD::FP_TO_SINT:         return lowerFP_TO_SINT(Op, DAG);
1229   }
1230   return SDValue();
1231 }
1232 
1233 //===----------------------------------------------------------------------===//
1234 //  Lower helper functions
1235 //===----------------------------------------------------------------------===//
1236 
1237 // addLiveIn - This helper function adds the specified physical register to the
1238 // MachineFunction as a live in value.  It also creates a corresponding
1239 // virtual register for it.
1240 static unsigned
1241 addLiveIn(MachineFunction &MF, unsigned PReg, const TargetRegisterClass *RC)
1242 {
1243   Register VReg = MF.getRegInfo().createVirtualRegister(RC);
1244   MF.getRegInfo().addLiveIn(PReg, VReg);
1245   return VReg;
1246 }
1247 
1248 static MachineBasicBlock *insertDivByZeroTrap(MachineInstr &MI,
1249                                               MachineBasicBlock &MBB,
1250                                               const TargetInstrInfo &TII,
1251                                               bool Is64Bit, bool IsMicroMips) {
1252   if (NoZeroDivCheck)
1253     return &MBB;
1254 
1255   // Insert instruction "teq $divisor_reg, $zero, 7".
1256   MachineBasicBlock::iterator I(MI);
1257   MachineInstrBuilder MIB;
1258   MachineOperand &Divisor = MI.getOperand(2);
1259   MIB = BuildMI(MBB, std::next(I), MI.getDebugLoc(),
1260                 TII.get(IsMicroMips ? Mips::TEQ_MM : Mips::TEQ))
1261             .addReg(Divisor.getReg(), getKillRegState(Divisor.isKill()))
1262             .addReg(Mips::ZERO)
1263             .addImm(7);
1264 
1265   // Use the 32-bit sub-register if this is a 64-bit division.
1266   if (Is64Bit)
1267     MIB->getOperand(0).setSubReg(Mips::sub_32);
1268 
1269   // Clear Divisor's kill flag.
1270   Divisor.setIsKill(false);
1271 
1272   // We would normally delete the original instruction here but in this case
1273   // we only needed to inject an additional instruction rather than replace it.
1274 
1275   return &MBB;
1276 }
1277 
1278 MachineBasicBlock *
1279 MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
1280                                                 MachineBasicBlock *BB) const {
1281   switch (MI.getOpcode()) {
1282   default:
1283     llvm_unreachable("Unexpected instr type to insert");
1284   case Mips::ATOMIC_LOAD_ADD_I8:
1285     return emitAtomicBinaryPartword(MI, BB, 1);
1286   case Mips::ATOMIC_LOAD_ADD_I16:
1287     return emitAtomicBinaryPartword(MI, BB, 2);
1288   case Mips::ATOMIC_LOAD_ADD_I32:
1289     return emitAtomicBinary(MI, BB);
1290   case Mips::ATOMIC_LOAD_ADD_I64:
1291     return emitAtomicBinary(MI, BB);
1292 
1293   case Mips::ATOMIC_LOAD_AND_I8:
1294     return emitAtomicBinaryPartword(MI, BB, 1);
1295   case Mips::ATOMIC_LOAD_AND_I16:
1296     return emitAtomicBinaryPartword(MI, BB, 2);
1297   case Mips::ATOMIC_LOAD_AND_I32:
1298     return emitAtomicBinary(MI, BB);
1299   case Mips::ATOMIC_LOAD_AND_I64:
1300     return emitAtomicBinary(MI, BB);
1301 
1302   case Mips::ATOMIC_LOAD_OR_I8:
1303     return emitAtomicBinaryPartword(MI, BB, 1);
1304   case Mips::ATOMIC_LOAD_OR_I16:
1305     return emitAtomicBinaryPartword(MI, BB, 2);
1306   case Mips::ATOMIC_LOAD_OR_I32:
1307     return emitAtomicBinary(MI, BB);
1308   case Mips::ATOMIC_LOAD_OR_I64:
1309     return emitAtomicBinary(MI, BB);
1310 
1311   case Mips::ATOMIC_LOAD_XOR_I8:
1312     return emitAtomicBinaryPartword(MI, BB, 1);
1313   case Mips::ATOMIC_LOAD_XOR_I16:
1314     return emitAtomicBinaryPartword(MI, BB, 2);
1315   case Mips::ATOMIC_LOAD_XOR_I32:
1316     return emitAtomicBinary(MI, BB);
1317   case Mips::ATOMIC_LOAD_XOR_I64:
1318     return emitAtomicBinary(MI, BB);
1319 
1320   case Mips::ATOMIC_LOAD_NAND_I8:
1321     return emitAtomicBinaryPartword(MI, BB, 1);
1322   case Mips::ATOMIC_LOAD_NAND_I16:
1323     return emitAtomicBinaryPartword(MI, BB, 2);
1324   case Mips::ATOMIC_LOAD_NAND_I32:
1325     return emitAtomicBinary(MI, BB);
1326   case Mips::ATOMIC_LOAD_NAND_I64:
1327     return emitAtomicBinary(MI, BB);
1328 
1329   case Mips::ATOMIC_LOAD_SUB_I8:
1330     return emitAtomicBinaryPartword(MI, BB, 1);
1331   case Mips::ATOMIC_LOAD_SUB_I16:
1332     return emitAtomicBinaryPartword(MI, BB, 2);
1333   case Mips::ATOMIC_LOAD_SUB_I32:
1334     return emitAtomicBinary(MI, BB);
1335   case Mips::ATOMIC_LOAD_SUB_I64:
1336     return emitAtomicBinary(MI, BB);
1337 
1338   case Mips::ATOMIC_SWAP_I8:
1339     return emitAtomicBinaryPartword(MI, BB, 1);
1340   case Mips::ATOMIC_SWAP_I16:
1341     return emitAtomicBinaryPartword(MI, BB, 2);
1342   case Mips::ATOMIC_SWAP_I32:
1343     return emitAtomicBinary(MI, BB);
1344   case Mips::ATOMIC_SWAP_I64:
1345     return emitAtomicBinary(MI, BB);
1346 
1347   case Mips::ATOMIC_CMP_SWAP_I8:
1348     return emitAtomicCmpSwapPartword(MI, BB, 1);
1349   case Mips::ATOMIC_CMP_SWAP_I16:
1350     return emitAtomicCmpSwapPartword(MI, BB, 2);
1351   case Mips::ATOMIC_CMP_SWAP_I32:
1352     return emitAtomicCmpSwap(MI, BB);
1353   case Mips::ATOMIC_CMP_SWAP_I64:
1354     return emitAtomicCmpSwap(MI, BB);
1355 
1356   case Mips::ATOMIC_LOAD_MIN_I8:
1357     return emitAtomicBinaryPartword(MI, BB, 1);
1358   case Mips::ATOMIC_LOAD_MIN_I16:
1359     return emitAtomicBinaryPartword(MI, BB, 2);
1360   case Mips::ATOMIC_LOAD_MIN_I32:
1361     return emitAtomicBinary(MI, BB);
1362   case Mips::ATOMIC_LOAD_MIN_I64:
1363     return emitAtomicBinary(MI, BB);
1364 
1365   case Mips::ATOMIC_LOAD_MAX_I8:
1366     return emitAtomicBinaryPartword(MI, BB, 1);
1367   case Mips::ATOMIC_LOAD_MAX_I16:
1368     return emitAtomicBinaryPartword(MI, BB, 2);
1369   case Mips::ATOMIC_LOAD_MAX_I32:
1370     return emitAtomicBinary(MI, BB);
1371   case Mips::ATOMIC_LOAD_MAX_I64:
1372     return emitAtomicBinary(MI, BB);
1373 
1374   case Mips::ATOMIC_LOAD_UMIN_I8:
1375     return emitAtomicBinaryPartword(MI, BB, 1);
1376   case Mips::ATOMIC_LOAD_UMIN_I16:
1377     return emitAtomicBinaryPartword(MI, BB, 2);
1378   case Mips::ATOMIC_LOAD_UMIN_I32:
1379     return emitAtomicBinary(MI, BB);
1380   case Mips::ATOMIC_LOAD_UMIN_I64:
1381     return emitAtomicBinary(MI, BB);
1382 
1383   case Mips::ATOMIC_LOAD_UMAX_I8:
1384     return emitAtomicBinaryPartword(MI, BB, 1);
1385   case Mips::ATOMIC_LOAD_UMAX_I16:
1386     return emitAtomicBinaryPartword(MI, BB, 2);
1387   case Mips::ATOMIC_LOAD_UMAX_I32:
1388     return emitAtomicBinary(MI, BB);
1389   case Mips::ATOMIC_LOAD_UMAX_I64:
1390     return emitAtomicBinary(MI, BB);
1391 
1392   case Mips::PseudoSDIV:
1393   case Mips::PseudoUDIV:
1394   case Mips::DIV:
1395   case Mips::DIVU:
1396   case Mips::MOD:
1397   case Mips::MODU:
1398     return insertDivByZeroTrap(MI, *BB, *Subtarget.getInstrInfo(), false,
1399                                false);
1400   case Mips::SDIV_MM_Pseudo:
1401   case Mips::UDIV_MM_Pseudo:
1402   case Mips::SDIV_MM:
1403   case Mips::UDIV_MM:
1404   case Mips::DIV_MMR6:
1405   case Mips::DIVU_MMR6:
1406   case Mips::MOD_MMR6:
1407   case Mips::MODU_MMR6:
1408     return insertDivByZeroTrap(MI, *BB, *Subtarget.getInstrInfo(), false, true);
1409   case Mips::PseudoDSDIV:
1410   case Mips::PseudoDUDIV:
1411   case Mips::DDIV:
1412   case Mips::DDIVU:
1413   case Mips::DMOD:
1414   case Mips::DMODU:
1415     return insertDivByZeroTrap(MI, *BB, *Subtarget.getInstrInfo(), true, false);
1416 
1417   case Mips::PseudoSELECT_I:
1418   case Mips::PseudoSELECT_I64:
1419   case Mips::PseudoSELECT_S:
1420   case Mips::PseudoSELECT_D32:
1421   case Mips::PseudoSELECT_D64:
1422     return emitPseudoSELECT(MI, BB, false, Mips::BNE);
1423   case Mips::PseudoSELECTFP_F_I:
1424   case Mips::PseudoSELECTFP_F_I64:
1425   case Mips::PseudoSELECTFP_F_S:
1426   case Mips::PseudoSELECTFP_F_D32:
1427   case Mips::PseudoSELECTFP_F_D64:
1428     return emitPseudoSELECT(MI, BB, true, Mips::BC1F);
1429   case Mips::PseudoSELECTFP_T_I:
1430   case Mips::PseudoSELECTFP_T_I64:
1431   case Mips::PseudoSELECTFP_T_S:
1432   case Mips::PseudoSELECTFP_T_D32:
1433   case Mips::PseudoSELECTFP_T_D64:
1434     return emitPseudoSELECT(MI, BB, true, Mips::BC1T);
1435   case Mips::PseudoD_SELECT_I:
1436   case Mips::PseudoD_SELECT_I64:
1437     return emitPseudoD_SELECT(MI, BB);
1438   case Mips::LDR_W:
1439     return emitLDR_W(MI, BB);
1440   case Mips::LDR_D:
1441     return emitLDR_D(MI, BB);
1442   case Mips::STR_W:
1443     return emitSTR_W(MI, BB);
1444   case Mips::STR_D:
1445     return emitSTR_D(MI, BB);
1446   }
1447 }
1448 
1449 // This function also handles Mips::ATOMIC_SWAP_I32 (when BinOpcode == 0), and
1450 // Mips::ATOMIC_LOAD_NAND_I32 (when Nand == true)
1451 MachineBasicBlock *
1452 MipsTargetLowering::emitAtomicBinary(MachineInstr &MI,
1453                                      MachineBasicBlock *BB) const {
1454 
1455   MachineFunction *MF = BB->getParent();
1456   MachineRegisterInfo &RegInfo = MF->getRegInfo();
1457   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
1458   DebugLoc DL = MI.getDebugLoc();
1459 
1460   unsigned AtomicOp;
1461   bool NeedsAdditionalReg = false;
1462   switch (MI.getOpcode()) {
1463   case Mips::ATOMIC_LOAD_ADD_I32:
1464     AtomicOp = Mips::ATOMIC_LOAD_ADD_I32_POSTRA;
1465     break;
1466   case Mips::ATOMIC_LOAD_SUB_I32:
1467     AtomicOp = Mips::ATOMIC_LOAD_SUB_I32_POSTRA;
1468     break;
1469   case Mips::ATOMIC_LOAD_AND_I32:
1470     AtomicOp = Mips::ATOMIC_LOAD_AND_I32_POSTRA;
1471     break;
1472   case Mips::ATOMIC_LOAD_OR_I32:
1473     AtomicOp = Mips::ATOMIC_LOAD_OR_I32_POSTRA;
1474     break;
1475   case Mips::ATOMIC_LOAD_XOR_I32:
1476     AtomicOp = Mips::ATOMIC_LOAD_XOR_I32_POSTRA;
1477     break;
1478   case Mips::ATOMIC_LOAD_NAND_I32:
1479     AtomicOp = Mips::ATOMIC_LOAD_NAND_I32_POSTRA;
1480     break;
1481   case Mips::ATOMIC_SWAP_I32:
1482     AtomicOp = Mips::ATOMIC_SWAP_I32_POSTRA;
1483     break;
1484   case Mips::ATOMIC_LOAD_ADD_I64:
1485     AtomicOp = Mips::ATOMIC_LOAD_ADD_I64_POSTRA;
1486     break;
1487   case Mips::ATOMIC_LOAD_SUB_I64:
1488     AtomicOp = Mips::ATOMIC_LOAD_SUB_I64_POSTRA;
1489     break;
1490   case Mips::ATOMIC_LOAD_AND_I64:
1491     AtomicOp = Mips::ATOMIC_LOAD_AND_I64_POSTRA;
1492     break;
1493   case Mips::ATOMIC_LOAD_OR_I64:
1494     AtomicOp = Mips::ATOMIC_LOAD_OR_I64_POSTRA;
1495     break;
1496   case Mips::ATOMIC_LOAD_XOR_I64:
1497     AtomicOp = Mips::ATOMIC_LOAD_XOR_I64_POSTRA;
1498     break;
1499   case Mips::ATOMIC_LOAD_NAND_I64:
1500     AtomicOp = Mips::ATOMIC_LOAD_NAND_I64_POSTRA;
1501     break;
1502   case Mips::ATOMIC_SWAP_I64:
1503     AtomicOp = Mips::ATOMIC_SWAP_I64_POSTRA;
1504     break;
1505   case Mips::ATOMIC_LOAD_MIN_I32:
1506     AtomicOp = Mips::ATOMIC_LOAD_MIN_I32_POSTRA;
1507     NeedsAdditionalReg = true;
1508     break;
1509   case Mips::ATOMIC_LOAD_MAX_I32:
1510     AtomicOp = Mips::ATOMIC_LOAD_MAX_I32_POSTRA;
1511     NeedsAdditionalReg = true;
1512     break;
1513   case Mips::ATOMIC_LOAD_UMIN_I32:
1514     AtomicOp = Mips::ATOMIC_LOAD_UMIN_I32_POSTRA;
1515     NeedsAdditionalReg = true;
1516     break;
1517   case Mips::ATOMIC_LOAD_UMAX_I32:
1518     AtomicOp = Mips::ATOMIC_LOAD_UMAX_I32_POSTRA;
1519     NeedsAdditionalReg = true;
1520     break;
1521   case Mips::ATOMIC_LOAD_MIN_I64:
1522     AtomicOp = Mips::ATOMIC_LOAD_MIN_I64_POSTRA;
1523     NeedsAdditionalReg = true;
1524     break;
1525   case Mips::ATOMIC_LOAD_MAX_I64:
1526     AtomicOp = Mips::ATOMIC_LOAD_MAX_I64_POSTRA;
1527     NeedsAdditionalReg = true;
1528     break;
1529   case Mips::ATOMIC_LOAD_UMIN_I64:
1530     AtomicOp = Mips::ATOMIC_LOAD_UMIN_I64_POSTRA;
1531     NeedsAdditionalReg = true;
1532     break;
1533   case Mips::ATOMIC_LOAD_UMAX_I64:
1534     AtomicOp = Mips::ATOMIC_LOAD_UMAX_I64_POSTRA;
1535     NeedsAdditionalReg = true;
1536     break;
1537   default:
1538     llvm_unreachable("Unknown pseudo atomic for replacement!");
1539   }
1540 
1541   Register OldVal = MI.getOperand(0).getReg();
1542   Register Ptr = MI.getOperand(1).getReg();
1543   Register Incr = MI.getOperand(2).getReg();
1544   Register Scratch = RegInfo.createVirtualRegister(RegInfo.getRegClass(OldVal));
1545 
1546   MachineBasicBlock::iterator II(MI);
1547 
1548   // The scratch registers here with the EarlyClobber | Define | Implicit
1549   // flags is used to persuade the register allocator and the machine
1550   // verifier to accept the usage of this register. This has to be a real
1551   // register which has an UNDEF value but is dead after the instruction which
1552   // is unique among the registers chosen for the instruction.
1553 
1554   // The EarlyClobber flag has the semantic properties that the operand it is
1555   // attached to is clobbered before the rest of the inputs are read. Hence it
1556   // must be unique among the operands to the instruction.
1557   // The Define flag is needed to coerce the machine verifier that an Undef
1558   // value isn't a problem.
1559   // The Dead flag is needed as the value in scratch isn't used by any other
1560   // instruction. Kill isn't used as Dead is more precise.
1561   // The implicit flag is here due to the interaction between the other flags
1562   // and the machine verifier.
1563 
1564   // For correctness purpose, a new pseudo is introduced here. We need this
1565   // new pseudo, so that FastRegisterAllocator does not see an ll/sc sequence
1566   // that is spread over >1 basic blocks. A register allocator which
1567   // introduces (or any codegen infact) a store, can violate the expectations
1568   // of the hardware.
1569   //
1570   // An atomic read-modify-write sequence starts with a linked load
1571   // instruction and ends with a store conditional instruction. The atomic
1572   // read-modify-write sequence fails if any of the following conditions
1573   // occur between the execution of ll and sc:
1574   //   * A coherent store is completed by another process or coherent I/O
1575   //     module into the block of synchronizable physical memory containing
1576   //     the word. The size and alignment of the block is
1577   //     implementation-dependent.
1578   //   * A coherent store is executed between an LL and SC sequence on the
1579   //     same processor to the block of synchornizable physical memory
1580   //     containing the word.
1581   //
1582 
1583   Register PtrCopy = RegInfo.createVirtualRegister(RegInfo.getRegClass(Ptr));
1584   Register IncrCopy = RegInfo.createVirtualRegister(RegInfo.getRegClass(Incr));
1585 
1586   BuildMI(*BB, II, DL, TII->get(Mips::COPY), IncrCopy).addReg(Incr);
1587   BuildMI(*BB, II, DL, TII->get(Mips::COPY), PtrCopy).addReg(Ptr);
1588 
1589   MachineInstrBuilder MIB =
1590       BuildMI(*BB, II, DL, TII->get(AtomicOp))
1591           .addReg(OldVal, RegState::Define | RegState::EarlyClobber)
1592           .addReg(PtrCopy)
1593           .addReg(IncrCopy)
1594           .addReg(Scratch, RegState::Define | RegState::EarlyClobber |
1595                                RegState::Implicit | RegState::Dead);
1596   if (NeedsAdditionalReg) {
1597     Register Scratch2 =
1598         RegInfo.createVirtualRegister(RegInfo.getRegClass(OldVal));
1599     MIB.addReg(Scratch2, RegState::Define | RegState::EarlyClobber |
1600                              RegState::Implicit | RegState::Dead);
1601   }
1602 
1603   MI.eraseFromParent();
1604 
1605   return BB;
1606 }
1607 
1608 MachineBasicBlock *MipsTargetLowering::emitSignExtendToI32InReg(
1609     MachineInstr &MI, MachineBasicBlock *BB, unsigned Size, unsigned DstReg,
1610     unsigned SrcReg) const {
1611   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
1612   const DebugLoc &DL = MI.getDebugLoc();
1613 
1614   if (Subtarget.hasMips32r2() && Size == 1) {
1615     BuildMI(BB, DL, TII->get(Mips::SEB), DstReg).addReg(SrcReg);
1616     return BB;
1617   }
1618 
1619   if (Subtarget.hasMips32r2() && Size == 2) {
1620     BuildMI(BB, DL, TII->get(Mips::SEH), DstReg).addReg(SrcReg);
1621     return BB;
1622   }
1623 
1624   MachineFunction *MF = BB->getParent();
1625   MachineRegisterInfo &RegInfo = MF->getRegInfo();
1626   const TargetRegisterClass *RC = getRegClassFor(MVT::i32);
1627   Register ScrReg = RegInfo.createVirtualRegister(RC);
1628 
1629   assert(Size < 32);
1630   int64_t ShiftImm = 32 - (Size * 8);
1631 
1632   BuildMI(BB, DL, TII->get(Mips::SLL), ScrReg).addReg(SrcReg).addImm(ShiftImm);
1633   BuildMI(BB, DL, TII->get(Mips::SRA), DstReg).addReg(ScrReg).addImm(ShiftImm);
1634 
1635   return BB;
1636 }
1637 
1638 MachineBasicBlock *MipsTargetLowering::emitAtomicBinaryPartword(
1639     MachineInstr &MI, MachineBasicBlock *BB, unsigned Size) const {
1640   assert((Size == 1 || Size == 2) &&
1641          "Unsupported size for EmitAtomicBinaryPartial.");
1642 
1643   MachineFunction *MF = BB->getParent();
1644   MachineRegisterInfo &RegInfo = MF->getRegInfo();
1645   const TargetRegisterClass *RC = getRegClassFor(MVT::i32);
1646   const bool ArePtrs64bit = ABI.ArePtrs64bit();
1647   const TargetRegisterClass *RCp =
1648     getRegClassFor(ArePtrs64bit ? MVT::i64 : MVT::i32);
1649   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
1650   DebugLoc DL = MI.getDebugLoc();
1651 
1652   Register Dest = MI.getOperand(0).getReg();
1653   Register Ptr = MI.getOperand(1).getReg();
1654   Register Incr = MI.getOperand(2).getReg();
1655 
1656   Register AlignedAddr = RegInfo.createVirtualRegister(RCp);
1657   Register ShiftAmt = RegInfo.createVirtualRegister(RC);
1658   Register Mask = RegInfo.createVirtualRegister(RC);
1659   Register Mask2 = RegInfo.createVirtualRegister(RC);
1660   Register Incr2 = RegInfo.createVirtualRegister(RC);
1661   Register MaskLSB2 = RegInfo.createVirtualRegister(RCp);
1662   Register PtrLSB2 = RegInfo.createVirtualRegister(RC);
1663   Register MaskUpper = RegInfo.createVirtualRegister(RC);
1664   Register Scratch = RegInfo.createVirtualRegister(RC);
1665   Register Scratch2 = RegInfo.createVirtualRegister(RC);
1666   Register Scratch3 = RegInfo.createVirtualRegister(RC);
1667 
1668   unsigned AtomicOp = 0;
1669   bool NeedsAdditionalReg = false;
1670   switch (MI.getOpcode()) {
1671   case Mips::ATOMIC_LOAD_NAND_I8:
1672     AtomicOp = Mips::ATOMIC_LOAD_NAND_I8_POSTRA;
1673     break;
1674   case Mips::ATOMIC_LOAD_NAND_I16:
1675     AtomicOp = Mips::ATOMIC_LOAD_NAND_I16_POSTRA;
1676     break;
1677   case Mips::ATOMIC_SWAP_I8:
1678     AtomicOp = Mips::ATOMIC_SWAP_I8_POSTRA;
1679     break;
1680   case Mips::ATOMIC_SWAP_I16:
1681     AtomicOp = Mips::ATOMIC_SWAP_I16_POSTRA;
1682     break;
1683   case Mips::ATOMIC_LOAD_ADD_I8:
1684     AtomicOp = Mips::ATOMIC_LOAD_ADD_I8_POSTRA;
1685     break;
1686   case Mips::ATOMIC_LOAD_ADD_I16:
1687     AtomicOp = Mips::ATOMIC_LOAD_ADD_I16_POSTRA;
1688     break;
1689   case Mips::ATOMIC_LOAD_SUB_I8:
1690     AtomicOp = Mips::ATOMIC_LOAD_SUB_I8_POSTRA;
1691     break;
1692   case Mips::ATOMIC_LOAD_SUB_I16:
1693     AtomicOp = Mips::ATOMIC_LOAD_SUB_I16_POSTRA;
1694     break;
1695   case Mips::ATOMIC_LOAD_AND_I8:
1696     AtomicOp = Mips::ATOMIC_LOAD_AND_I8_POSTRA;
1697     break;
1698   case Mips::ATOMIC_LOAD_AND_I16:
1699     AtomicOp = Mips::ATOMIC_LOAD_AND_I16_POSTRA;
1700     break;
1701   case Mips::ATOMIC_LOAD_OR_I8:
1702     AtomicOp = Mips::ATOMIC_LOAD_OR_I8_POSTRA;
1703     break;
1704   case Mips::ATOMIC_LOAD_OR_I16:
1705     AtomicOp = Mips::ATOMIC_LOAD_OR_I16_POSTRA;
1706     break;
1707   case Mips::ATOMIC_LOAD_XOR_I8:
1708     AtomicOp = Mips::ATOMIC_LOAD_XOR_I8_POSTRA;
1709     break;
1710   case Mips::ATOMIC_LOAD_XOR_I16:
1711     AtomicOp = Mips::ATOMIC_LOAD_XOR_I16_POSTRA;
1712     break;
1713   case Mips::ATOMIC_LOAD_MIN_I8:
1714     AtomicOp = Mips::ATOMIC_LOAD_MIN_I8_POSTRA;
1715     NeedsAdditionalReg = true;
1716     break;
1717   case Mips::ATOMIC_LOAD_MIN_I16:
1718     AtomicOp = Mips::ATOMIC_LOAD_MIN_I16_POSTRA;
1719     NeedsAdditionalReg = true;
1720     break;
1721   case Mips::ATOMIC_LOAD_MAX_I8:
1722     AtomicOp = Mips::ATOMIC_LOAD_MAX_I8_POSTRA;
1723     NeedsAdditionalReg = true;
1724     break;
1725   case Mips::ATOMIC_LOAD_MAX_I16:
1726     AtomicOp = Mips::ATOMIC_LOAD_MAX_I16_POSTRA;
1727     NeedsAdditionalReg = true;
1728     break;
1729   case Mips::ATOMIC_LOAD_UMIN_I8:
1730     AtomicOp = Mips::ATOMIC_LOAD_UMIN_I8_POSTRA;
1731     NeedsAdditionalReg = true;
1732     break;
1733   case Mips::ATOMIC_LOAD_UMIN_I16:
1734     AtomicOp = Mips::ATOMIC_LOAD_UMIN_I16_POSTRA;
1735     NeedsAdditionalReg = true;
1736     break;
1737   case Mips::ATOMIC_LOAD_UMAX_I8:
1738     AtomicOp = Mips::ATOMIC_LOAD_UMAX_I8_POSTRA;
1739     NeedsAdditionalReg = true;
1740     break;
1741   case Mips::ATOMIC_LOAD_UMAX_I16:
1742     AtomicOp = Mips::ATOMIC_LOAD_UMAX_I16_POSTRA;
1743     NeedsAdditionalReg = true;
1744     break;
1745   default:
1746     llvm_unreachable("Unknown subword atomic pseudo for expansion!");
1747   }
1748 
1749   // insert new blocks after the current block
1750   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1751   MachineBasicBlock *exitMBB = MF->CreateMachineBasicBlock(LLVM_BB);
1752   MachineFunction::iterator It = ++BB->getIterator();
1753   MF->insert(It, exitMBB);
1754 
1755   // Transfer the remainder of BB and its successor edges to exitMBB.
1756   exitMBB->splice(exitMBB->begin(), BB,
1757                   std::next(MachineBasicBlock::iterator(MI)), BB->end());
1758   exitMBB->transferSuccessorsAndUpdatePHIs(BB);
1759 
1760   BB->addSuccessor(exitMBB, BranchProbability::getOne());
1761 
1762   //  thisMBB:
1763   //    addiu   masklsb2,$0,-4                # 0xfffffffc
1764   //    and     alignedaddr,ptr,masklsb2
1765   //    andi    ptrlsb2,ptr,3
1766   //    sll     shiftamt,ptrlsb2,3
1767   //    ori     maskupper,$0,255               # 0xff
1768   //    sll     mask,maskupper,shiftamt
1769   //    nor     mask2,$0,mask
1770   //    sll     incr2,incr,shiftamt
1771 
1772   int64_t MaskImm = (Size == 1) ? 255 : 65535;
1773   BuildMI(BB, DL, TII->get(ABI.GetPtrAddiuOp()), MaskLSB2)
1774     .addReg(ABI.GetNullPtr()).addImm(-4);
1775   BuildMI(BB, DL, TII->get(ABI.GetPtrAndOp()), AlignedAddr)
1776     .addReg(Ptr).addReg(MaskLSB2);
1777   BuildMI(BB, DL, TII->get(Mips::ANDi), PtrLSB2)
1778       .addReg(Ptr, 0, ArePtrs64bit ? Mips::sub_32 : 0).addImm(3);
1779   if (Subtarget.isLittle()) {
1780     BuildMI(BB, DL, TII->get(Mips::SLL), ShiftAmt).addReg(PtrLSB2).addImm(3);
1781   } else {
1782     Register Off = RegInfo.createVirtualRegister(RC);
1783     BuildMI(BB, DL, TII->get(Mips::XORi), Off)
1784       .addReg(PtrLSB2).addImm((Size == 1) ? 3 : 2);
1785     BuildMI(BB, DL, TII->get(Mips::SLL), ShiftAmt).addReg(Off).addImm(3);
1786   }
1787   BuildMI(BB, DL, TII->get(Mips::ORi), MaskUpper)
1788     .addReg(Mips::ZERO).addImm(MaskImm);
1789   BuildMI(BB, DL, TII->get(Mips::SLLV), Mask)
1790     .addReg(MaskUpper).addReg(ShiftAmt);
1791   BuildMI(BB, DL, TII->get(Mips::NOR), Mask2).addReg(Mips::ZERO).addReg(Mask);
1792   BuildMI(BB, DL, TII->get(Mips::SLLV), Incr2).addReg(Incr).addReg(ShiftAmt);
1793 
1794 
1795   // The purposes of the flags on the scratch registers is explained in
1796   // emitAtomicBinary. In summary, we need a scratch register which is going to
1797   // be undef, that is unique among registers chosen for the instruction.
1798 
1799   MachineInstrBuilder MIB =
1800       BuildMI(BB, DL, TII->get(AtomicOp))
1801           .addReg(Dest, RegState::Define | RegState::EarlyClobber)
1802           .addReg(AlignedAddr)
1803           .addReg(Incr2)
1804           .addReg(Mask)
1805           .addReg(Mask2)
1806           .addReg(ShiftAmt)
1807           .addReg(Scratch, RegState::EarlyClobber | RegState::Define |
1808                                RegState::Dead | RegState::Implicit)
1809           .addReg(Scratch2, RegState::EarlyClobber | RegState::Define |
1810                                 RegState::Dead | RegState::Implicit)
1811           .addReg(Scratch3, RegState::EarlyClobber | RegState::Define |
1812                                 RegState::Dead | RegState::Implicit);
1813   if (NeedsAdditionalReg) {
1814     Register Scratch4 = RegInfo.createVirtualRegister(RC);
1815     MIB.addReg(Scratch4, RegState::EarlyClobber | RegState::Define |
1816                              RegState::Dead | RegState::Implicit);
1817   }
1818 
1819   MI.eraseFromParent(); // The instruction is gone now.
1820 
1821   return exitMBB;
1822 }
1823 
1824 // Lower atomic compare and swap to a pseudo instruction, taking care to
1825 // define a scratch register for the pseudo instruction's expansion. The
1826 // instruction is expanded after the register allocator as to prevent
1827 // the insertion of stores between the linked load and the store conditional.
1828 
1829 MachineBasicBlock *
1830 MipsTargetLowering::emitAtomicCmpSwap(MachineInstr &MI,
1831                                       MachineBasicBlock *BB) const {
1832 
1833   assert((MI.getOpcode() == Mips::ATOMIC_CMP_SWAP_I32 ||
1834           MI.getOpcode() == Mips::ATOMIC_CMP_SWAP_I64) &&
1835          "Unsupported atomic pseudo for EmitAtomicCmpSwap.");
1836 
1837   const unsigned Size = MI.getOpcode() == Mips::ATOMIC_CMP_SWAP_I32 ? 4 : 8;
1838 
1839   MachineFunction *MF = BB->getParent();
1840   MachineRegisterInfo &MRI = MF->getRegInfo();
1841   const TargetRegisterClass *RC = getRegClassFor(MVT::getIntegerVT(Size * 8));
1842   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
1843   DebugLoc DL = MI.getDebugLoc();
1844 
1845   unsigned AtomicOp = MI.getOpcode() == Mips::ATOMIC_CMP_SWAP_I32
1846                           ? Mips::ATOMIC_CMP_SWAP_I32_POSTRA
1847                           : Mips::ATOMIC_CMP_SWAP_I64_POSTRA;
1848   Register Dest = MI.getOperand(0).getReg();
1849   Register Ptr = MI.getOperand(1).getReg();
1850   Register OldVal = MI.getOperand(2).getReg();
1851   Register NewVal = MI.getOperand(3).getReg();
1852 
1853   Register Scratch = MRI.createVirtualRegister(RC);
1854   MachineBasicBlock::iterator II(MI);
1855 
1856   // We need to create copies of the various registers and kill them at the
1857   // atomic pseudo. If the copies are not made, when the atomic is expanded
1858   // after fast register allocation, the spills will end up outside of the
1859   // blocks that their values are defined in, causing livein errors.
1860 
1861   Register PtrCopy = MRI.createVirtualRegister(MRI.getRegClass(Ptr));
1862   Register OldValCopy = MRI.createVirtualRegister(MRI.getRegClass(OldVal));
1863   Register NewValCopy = MRI.createVirtualRegister(MRI.getRegClass(NewVal));
1864 
1865   BuildMI(*BB, II, DL, TII->get(Mips::COPY), PtrCopy).addReg(Ptr);
1866   BuildMI(*BB, II, DL, TII->get(Mips::COPY), OldValCopy).addReg(OldVal);
1867   BuildMI(*BB, II, DL, TII->get(Mips::COPY), NewValCopy).addReg(NewVal);
1868 
1869   // The purposes of the flags on the scratch registers is explained in
1870   // emitAtomicBinary. In summary, we need a scratch register which is going to
1871   // be undef, that is unique among registers chosen for the instruction.
1872 
1873   BuildMI(*BB, II, DL, TII->get(AtomicOp))
1874       .addReg(Dest, RegState::Define | RegState::EarlyClobber)
1875       .addReg(PtrCopy, RegState::Kill)
1876       .addReg(OldValCopy, RegState::Kill)
1877       .addReg(NewValCopy, RegState::Kill)
1878       .addReg(Scratch, RegState::EarlyClobber | RegState::Define |
1879                            RegState::Dead | RegState::Implicit);
1880 
1881   MI.eraseFromParent(); // The instruction is gone now.
1882 
1883   return BB;
1884 }
1885 
1886 MachineBasicBlock *MipsTargetLowering::emitAtomicCmpSwapPartword(
1887     MachineInstr &MI, MachineBasicBlock *BB, unsigned Size) const {
1888   assert((Size == 1 || Size == 2) &&
1889       "Unsupported size for EmitAtomicCmpSwapPartial.");
1890 
1891   MachineFunction *MF = BB->getParent();
1892   MachineRegisterInfo &RegInfo = MF->getRegInfo();
1893   const TargetRegisterClass *RC = getRegClassFor(MVT::i32);
1894   const bool ArePtrs64bit = ABI.ArePtrs64bit();
1895   const TargetRegisterClass *RCp =
1896     getRegClassFor(ArePtrs64bit ? MVT::i64 : MVT::i32);
1897   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
1898   DebugLoc DL = MI.getDebugLoc();
1899 
1900   Register Dest = MI.getOperand(0).getReg();
1901   Register Ptr = MI.getOperand(1).getReg();
1902   Register CmpVal = MI.getOperand(2).getReg();
1903   Register NewVal = MI.getOperand(3).getReg();
1904 
1905   Register AlignedAddr = RegInfo.createVirtualRegister(RCp);
1906   Register ShiftAmt = RegInfo.createVirtualRegister(RC);
1907   Register Mask = RegInfo.createVirtualRegister(RC);
1908   Register Mask2 = RegInfo.createVirtualRegister(RC);
1909   Register ShiftedCmpVal = RegInfo.createVirtualRegister(RC);
1910   Register ShiftedNewVal = RegInfo.createVirtualRegister(RC);
1911   Register MaskLSB2 = RegInfo.createVirtualRegister(RCp);
1912   Register PtrLSB2 = RegInfo.createVirtualRegister(RC);
1913   Register MaskUpper = RegInfo.createVirtualRegister(RC);
1914   Register MaskedCmpVal = RegInfo.createVirtualRegister(RC);
1915   Register MaskedNewVal = RegInfo.createVirtualRegister(RC);
1916   unsigned AtomicOp = MI.getOpcode() == Mips::ATOMIC_CMP_SWAP_I8
1917                           ? Mips::ATOMIC_CMP_SWAP_I8_POSTRA
1918                           : Mips::ATOMIC_CMP_SWAP_I16_POSTRA;
1919 
1920   // The scratch registers here with the EarlyClobber | Define | Dead | Implicit
1921   // flags are used to coerce the register allocator and the machine verifier to
1922   // accept the usage of these registers.
1923   // The EarlyClobber flag has the semantic properties that the operand it is
1924   // attached to is clobbered before the rest of the inputs are read. Hence it
1925   // must be unique among the operands to the instruction.
1926   // The Define flag is needed to coerce the machine verifier that an Undef
1927   // value isn't a problem.
1928   // The Dead flag is needed as the value in scratch isn't used by any other
1929   // instruction. Kill isn't used as Dead is more precise.
1930   Register Scratch = RegInfo.createVirtualRegister(RC);
1931   Register Scratch2 = RegInfo.createVirtualRegister(RC);
1932 
1933   // insert new blocks after the current block
1934   const BasicBlock *LLVM_BB = BB->getBasicBlock();
1935   MachineBasicBlock *exitMBB = MF->CreateMachineBasicBlock(LLVM_BB);
1936   MachineFunction::iterator It = ++BB->getIterator();
1937   MF->insert(It, exitMBB);
1938 
1939   // Transfer the remainder of BB and its successor edges to exitMBB.
1940   exitMBB->splice(exitMBB->begin(), BB,
1941                   std::next(MachineBasicBlock::iterator(MI)), BB->end());
1942   exitMBB->transferSuccessorsAndUpdatePHIs(BB);
1943 
1944   BB->addSuccessor(exitMBB, BranchProbability::getOne());
1945 
1946   //  thisMBB:
1947   //    addiu   masklsb2,$0,-4                # 0xfffffffc
1948   //    and     alignedaddr,ptr,masklsb2
1949   //    andi    ptrlsb2,ptr,3
1950   //    xori    ptrlsb2,ptrlsb2,3              # Only for BE
1951   //    sll     shiftamt,ptrlsb2,3
1952   //    ori     maskupper,$0,255               # 0xff
1953   //    sll     mask,maskupper,shiftamt
1954   //    nor     mask2,$0,mask
1955   //    andi    maskedcmpval,cmpval,255
1956   //    sll     shiftedcmpval,maskedcmpval,shiftamt
1957   //    andi    maskednewval,newval,255
1958   //    sll     shiftednewval,maskednewval,shiftamt
1959   int64_t MaskImm = (Size == 1) ? 255 : 65535;
1960   BuildMI(BB, DL, TII->get(ArePtrs64bit ? Mips::DADDiu : Mips::ADDiu), MaskLSB2)
1961     .addReg(ABI.GetNullPtr()).addImm(-4);
1962   BuildMI(BB, DL, TII->get(ArePtrs64bit ? Mips::AND64 : Mips::AND), AlignedAddr)
1963     .addReg(Ptr).addReg(MaskLSB2);
1964   BuildMI(BB, DL, TII->get(Mips::ANDi), PtrLSB2)
1965       .addReg(Ptr, 0, ArePtrs64bit ? Mips::sub_32 : 0).addImm(3);
1966   if (Subtarget.isLittle()) {
1967     BuildMI(BB, DL, TII->get(Mips::SLL), ShiftAmt).addReg(PtrLSB2).addImm(3);
1968   } else {
1969     Register Off = RegInfo.createVirtualRegister(RC);
1970     BuildMI(BB, DL, TII->get(Mips::XORi), Off)
1971       .addReg(PtrLSB2).addImm((Size == 1) ? 3 : 2);
1972     BuildMI(BB, DL, TII->get(Mips::SLL), ShiftAmt).addReg(Off).addImm(3);
1973   }
1974   BuildMI(BB, DL, TII->get(Mips::ORi), MaskUpper)
1975     .addReg(Mips::ZERO).addImm(MaskImm);
1976   BuildMI(BB, DL, TII->get(Mips::SLLV), Mask)
1977     .addReg(MaskUpper).addReg(ShiftAmt);
1978   BuildMI(BB, DL, TII->get(Mips::NOR), Mask2).addReg(Mips::ZERO).addReg(Mask);
1979   BuildMI(BB, DL, TII->get(Mips::ANDi), MaskedCmpVal)
1980     .addReg(CmpVal).addImm(MaskImm);
1981   BuildMI(BB, DL, TII->get(Mips::SLLV), ShiftedCmpVal)
1982     .addReg(MaskedCmpVal).addReg(ShiftAmt);
1983   BuildMI(BB, DL, TII->get(Mips::ANDi), MaskedNewVal)
1984     .addReg(NewVal).addImm(MaskImm);
1985   BuildMI(BB, DL, TII->get(Mips::SLLV), ShiftedNewVal)
1986     .addReg(MaskedNewVal).addReg(ShiftAmt);
1987 
1988   // The purposes of the flags on the scratch registers are explained in
1989   // emitAtomicBinary. In summary, we need a scratch register which is going to
1990   // be undef, that is unique among the register chosen for the instruction.
1991 
1992   BuildMI(BB, DL, TII->get(AtomicOp))
1993       .addReg(Dest, RegState::Define | RegState::EarlyClobber)
1994       .addReg(AlignedAddr)
1995       .addReg(Mask)
1996       .addReg(ShiftedCmpVal)
1997       .addReg(Mask2)
1998       .addReg(ShiftedNewVal)
1999       .addReg(ShiftAmt)
2000       .addReg(Scratch, RegState::EarlyClobber | RegState::Define |
2001                            RegState::Dead | RegState::Implicit)
2002       .addReg(Scratch2, RegState::EarlyClobber | RegState::Define |
2003                             RegState::Dead | RegState::Implicit);
2004 
2005   MI.eraseFromParent(); // The instruction is gone now.
2006 
2007   return exitMBB;
2008 }
2009 
2010 SDValue MipsTargetLowering::lowerBRCOND(SDValue Op, SelectionDAG &DAG) const {
2011   // The first operand is the chain, the second is the condition, the third is
2012   // the block to branch to if the condition is true.
2013   SDValue Chain = Op.getOperand(0);
2014   SDValue Dest = Op.getOperand(2);
2015   SDLoc DL(Op);
2016 
2017   assert(!Subtarget.hasMips32r6() && !Subtarget.hasMips64r6());
2018   SDValue CondRes = createFPCmp(DAG, Op.getOperand(1));
2019 
2020   // Return if flag is not set by a floating point comparison.
2021   if (CondRes.getOpcode() != MipsISD::FPCmp)
2022     return Op;
2023 
2024   SDValue CCNode  = CondRes.getOperand(2);
2025   Mips::CondCode CC =
2026     (Mips::CondCode)cast<ConstantSDNode>(CCNode)->getZExtValue();
2027   unsigned Opc = invertFPCondCodeUser(CC) ? Mips::BRANCH_F : Mips::BRANCH_T;
2028   SDValue BrCode = DAG.getConstant(Opc, DL, MVT::i32);
2029   SDValue FCC0 = DAG.getRegister(Mips::FCC0, MVT::i32);
2030   return DAG.getNode(MipsISD::FPBrcond, DL, Op.getValueType(), Chain, BrCode,
2031                      FCC0, Dest, CondRes);
2032 }
2033 
2034 SDValue MipsTargetLowering::
2035 lowerSELECT(SDValue Op, SelectionDAG &DAG) const
2036 {
2037   assert(!Subtarget.hasMips32r6() && !Subtarget.hasMips64r6());
2038   SDValue Cond = createFPCmp(DAG, Op.getOperand(0));
2039 
2040   // Return if flag is not set by a floating point comparison.
2041   if (Cond.getOpcode() != MipsISD::FPCmp)
2042     return Op;
2043 
2044   return createCMovFP(DAG, Cond, Op.getOperand(1), Op.getOperand(2),
2045                       SDLoc(Op));
2046 }
2047 
2048 SDValue MipsTargetLowering::lowerSETCC(SDValue Op, SelectionDAG &DAG) const {
2049   assert(!Subtarget.hasMips32r6() && !Subtarget.hasMips64r6());
2050   SDValue Cond = createFPCmp(DAG, Op);
2051 
2052   assert(Cond.getOpcode() == MipsISD::FPCmp &&
2053          "Floating point operand expected.");
2054 
2055   SDLoc DL(Op);
2056   SDValue True  = DAG.getConstant(1, DL, MVT::i32);
2057   SDValue False = DAG.getConstant(0, DL, MVT::i32);
2058 
2059   return createCMovFP(DAG, Cond, True, False, DL);
2060 }
2061 
2062 SDValue MipsTargetLowering::lowerGlobalAddress(SDValue Op,
2063                                                SelectionDAG &DAG) const {
2064   EVT Ty = Op.getValueType();
2065   GlobalAddressSDNode *N = cast<GlobalAddressSDNode>(Op);
2066   const GlobalValue *GV = N->getGlobal();
2067 
2068   if (!isPositionIndependent()) {
2069     const MipsTargetObjectFile *TLOF =
2070         static_cast<const MipsTargetObjectFile *>(
2071             getTargetMachine().getObjFileLowering());
2072     const GlobalObject *GO = GV->getAliaseeObject();
2073     if (GO && TLOF->IsGlobalInSmallSection(GO, getTargetMachine()))
2074       // %gp_rel relocation
2075       return getAddrGPRel(N, SDLoc(N), Ty, DAG, ABI.IsN64());
2076 
2077                                 // %hi/%lo relocation
2078     return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
2079                                 // %highest/%higher/%hi/%lo relocation
2080                                 : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
2081   }
2082 
2083   // Every other architecture would use shouldAssumeDSOLocal in here, but
2084   // mips is special.
2085   // * In PIC code mips requires got loads even for local statics!
2086   // * To save on got entries, for local statics the got entry contains the
2087   //   page and an additional add instruction takes care of the low bits.
2088   // * It is legal to access a hidden symbol with a non hidden undefined,
2089   //   so one cannot guarantee that all access to a hidden symbol will know
2090   //   it is hidden.
2091   // * Mips linkers don't support creating a page and a full got entry for
2092   //   the same symbol.
2093   // * Given all that, we have to use a full got entry for hidden symbols :-(
2094   if (GV->hasLocalLinkage())
2095     return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
2096 
2097   if (Subtarget.useXGOT())
2098     return getAddrGlobalLargeGOT(
2099         N, SDLoc(N), Ty, DAG, MipsII::MO_GOT_HI16, MipsII::MO_GOT_LO16,
2100         DAG.getEntryNode(),
2101         MachinePointerInfo::getGOT(DAG.getMachineFunction()));
2102 
2103   return getAddrGlobal(
2104       N, SDLoc(N), Ty, DAG,
2105       (ABI.IsN32() || ABI.IsN64()) ? MipsII::MO_GOT_DISP : MipsII::MO_GOT,
2106       DAG.getEntryNode(), MachinePointerInfo::getGOT(DAG.getMachineFunction()));
2107 }
2108 
2109 SDValue MipsTargetLowering::lowerBlockAddress(SDValue Op,
2110                                               SelectionDAG &DAG) const {
2111   BlockAddressSDNode *N = cast<BlockAddressSDNode>(Op);
2112   EVT Ty = Op.getValueType();
2113 
2114   if (!isPositionIndependent())
2115     return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
2116                                 : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
2117 
2118   return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
2119 }
2120 
2121 SDValue MipsTargetLowering::
2122 lowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const
2123 {
2124   // If the relocation model is PIC, use the General Dynamic TLS Model or
2125   // Local Dynamic TLS model, otherwise use the Initial Exec or
2126   // Local Exec TLS Model.
2127 
2128   GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(Op);
2129   if (DAG.getTarget().useEmulatedTLS())
2130     return LowerToTLSEmulatedModel(GA, DAG);
2131 
2132   SDLoc DL(GA);
2133   const GlobalValue *GV = GA->getGlobal();
2134   EVT PtrVT = getPointerTy(DAG.getDataLayout());
2135 
2136   TLSModel::Model model = getTargetMachine().getTLSModel(GV);
2137 
2138   if (model == TLSModel::GeneralDynamic || model == TLSModel::LocalDynamic) {
2139     // General Dynamic and Local Dynamic TLS Model.
2140     unsigned Flag = (model == TLSModel::LocalDynamic) ? MipsII::MO_TLSLDM
2141                                                       : MipsII::MO_TLSGD;
2142 
2143     SDValue TGA = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0, Flag);
2144     SDValue Argument = DAG.getNode(MipsISD::Wrapper, DL, PtrVT,
2145                                    getGlobalReg(DAG, PtrVT), TGA);
2146     unsigned PtrSize = PtrVT.getSizeInBits();
2147     IntegerType *PtrTy = Type::getIntNTy(*DAG.getContext(), PtrSize);
2148 
2149     SDValue TlsGetAddr = DAG.getExternalSymbol("__tls_get_addr", PtrVT);
2150 
2151     ArgListTy Args;
2152     ArgListEntry Entry;
2153     Entry.Node = Argument;
2154     Entry.Ty = PtrTy;
2155     Args.push_back(Entry);
2156 
2157     TargetLowering::CallLoweringInfo CLI(DAG);
2158     CLI.setDebugLoc(DL)
2159         .setChain(DAG.getEntryNode())
2160         .setLibCallee(CallingConv::C, PtrTy, TlsGetAddr, std::move(Args));
2161     std::pair<SDValue, SDValue> CallResult = LowerCallTo(CLI);
2162 
2163     SDValue Ret = CallResult.first;
2164 
2165     if (model != TLSModel::LocalDynamic)
2166       return Ret;
2167 
2168     SDValue TGAHi = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0,
2169                                                MipsII::MO_DTPREL_HI);
2170     SDValue Hi = DAG.getNode(MipsISD::TlsHi, DL, PtrVT, TGAHi);
2171     SDValue TGALo = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0,
2172                                                MipsII::MO_DTPREL_LO);
2173     SDValue Lo = DAG.getNode(MipsISD::Lo, DL, PtrVT, TGALo);
2174     SDValue Add = DAG.getNode(ISD::ADD, DL, PtrVT, Hi, Ret);
2175     return DAG.getNode(ISD::ADD, DL, PtrVT, Add, Lo);
2176   }
2177 
2178   SDValue Offset;
2179   if (model == TLSModel::InitialExec) {
2180     // Initial Exec TLS Model
2181     SDValue TGA = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0,
2182                                              MipsII::MO_GOTTPREL);
2183     TGA = DAG.getNode(MipsISD::Wrapper, DL, PtrVT, getGlobalReg(DAG, PtrVT),
2184                       TGA);
2185     Offset =
2186         DAG.getLoad(PtrVT, DL, DAG.getEntryNode(), TGA, MachinePointerInfo());
2187   } else {
2188     // Local Exec TLS Model
2189     assert(model == TLSModel::LocalExec);
2190     SDValue TGAHi = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0,
2191                                                MipsII::MO_TPREL_HI);
2192     SDValue TGALo = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0,
2193                                                MipsII::MO_TPREL_LO);
2194     SDValue Hi = DAG.getNode(MipsISD::TlsHi, DL, PtrVT, TGAHi);
2195     SDValue Lo = DAG.getNode(MipsISD::Lo, DL, PtrVT, TGALo);
2196     Offset = DAG.getNode(ISD::ADD, DL, PtrVT, Hi, Lo);
2197   }
2198 
2199   SDValue ThreadPointer = DAG.getNode(MipsISD::ThreadPointer, DL, PtrVT);
2200   return DAG.getNode(ISD::ADD, DL, PtrVT, ThreadPointer, Offset);
2201 }
2202 
2203 SDValue MipsTargetLowering::
2204 lowerJumpTable(SDValue Op, SelectionDAG &DAG) const
2205 {
2206   JumpTableSDNode *N = cast<JumpTableSDNode>(Op);
2207   EVT Ty = Op.getValueType();
2208 
2209   if (!isPositionIndependent())
2210     return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
2211                                 : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
2212 
2213   return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
2214 }
2215 
2216 SDValue MipsTargetLowering::
2217 lowerConstantPool(SDValue Op, SelectionDAG &DAG) const
2218 {
2219   ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
2220   EVT Ty = Op.getValueType();
2221 
2222   if (!isPositionIndependent()) {
2223     const MipsTargetObjectFile *TLOF =
2224         static_cast<const MipsTargetObjectFile *>(
2225             getTargetMachine().getObjFileLowering());
2226 
2227     if (TLOF->IsConstantInSmallSection(DAG.getDataLayout(), N->getConstVal(),
2228                                        getTargetMachine()))
2229       // %gp_rel relocation
2230       return getAddrGPRel(N, SDLoc(N), Ty, DAG, ABI.IsN64());
2231 
2232     return Subtarget.hasSym32() ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
2233                                 : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
2234   }
2235 
2236  return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
2237 }
2238 
2239 SDValue MipsTargetLowering::lowerVASTART(SDValue Op, SelectionDAG &DAG) const {
2240   MachineFunction &MF = DAG.getMachineFunction();
2241   MipsFunctionInfo *FuncInfo = MF.getInfo<MipsFunctionInfo>();
2242 
2243   SDLoc DL(Op);
2244   SDValue FI = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(),
2245                                  getPointerTy(MF.getDataLayout()));
2246 
2247   // vastart just stores the address of the VarArgsFrameIndex slot into the
2248   // memory location argument.
2249   const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
2250   return DAG.getStore(Op.getOperand(0), DL, FI, Op.getOperand(1),
2251                       MachinePointerInfo(SV));
2252 }
2253 
2254 SDValue MipsTargetLowering::lowerVAARG(SDValue Op, SelectionDAG &DAG) const {
2255   SDNode *Node = Op.getNode();
2256   EVT VT = Node->getValueType(0);
2257   SDValue Chain = Node->getOperand(0);
2258   SDValue VAListPtr = Node->getOperand(1);
2259   const Align Align =
2260       llvm::MaybeAlign(Node->getConstantOperandVal(3)).valueOrOne();
2261   const Value *SV = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
2262   SDLoc DL(Node);
2263   unsigned ArgSlotSizeInBytes = (ABI.IsN32() || ABI.IsN64()) ? 8 : 4;
2264 
2265   SDValue VAListLoad = DAG.getLoad(getPointerTy(DAG.getDataLayout()), DL, Chain,
2266                                    VAListPtr, MachinePointerInfo(SV));
2267   SDValue VAList = VAListLoad;
2268 
2269   // Re-align the pointer if necessary.
2270   // It should only ever be necessary for 64-bit types on O32 since the minimum
2271   // argument alignment is the same as the maximum type alignment for N32/N64.
2272   //
2273   // FIXME: We currently align too often. The code generator doesn't notice
2274   //        when the pointer is still aligned from the last va_arg (or pair of
2275   //        va_args for the i64 on O32 case).
2276   if (Align > getMinStackArgumentAlignment()) {
2277     VAList = DAG.getNode(
2278         ISD::ADD, DL, VAList.getValueType(), VAList,
2279         DAG.getConstant(Align.value() - 1, DL, VAList.getValueType()));
2280 
2281     VAList = DAG.getNode(
2282         ISD::AND, DL, VAList.getValueType(), VAList,
2283         DAG.getConstant(-(int64_t)Align.value(), DL, VAList.getValueType()));
2284   }
2285 
2286   // Increment the pointer, VAList, to the next vaarg.
2287   auto &TD = DAG.getDataLayout();
2288   unsigned ArgSizeInBytes =
2289       TD.getTypeAllocSize(VT.getTypeForEVT(*DAG.getContext()));
2290   SDValue Tmp3 =
2291       DAG.getNode(ISD::ADD, DL, VAList.getValueType(), VAList,
2292                   DAG.getConstant(alignTo(ArgSizeInBytes, ArgSlotSizeInBytes),
2293                                   DL, VAList.getValueType()));
2294   // Store the incremented VAList to the legalized pointer
2295   Chain = DAG.getStore(VAListLoad.getValue(1), DL, Tmp3, VAListPtr,
2296                        MachinePointerInfo(SV));
2297 
2298   // In big-endian mode we must adjust the pointer when the load size is smaller
2299   // than the argument slot size. We must also reduce the known alignment to
2300   // match. For example in the N64 ABI, we must add 4 bytes to the offset to get
2301   // the correct half of the slot, and reduce the alignment from 8 (slot
2302   // alignment) down to 4 (type alignment).
2303   if (!Subtarget.isLittle() && ArgSizeInBytes < ArgSlotSizeInBytes) {
2304     unsigned Adjustment = ArgSlotSizeInBytes - ArgSizeInBytes;
2305     VAList = DAG.getNode(ISD::ADD, DL, VAListPtr.getValueType(), VAList,
2306                          DAG.getIntPtrConstant(Adjustment, DL));
2307   }
2308   // Load the actual argument out of the pointer VAList
2309   return DAG.getLoad(VT, DL, Chain, VAList, MachinePointerInfo());
2310 }
2311 
2312 static SDValue lowerFCOPYSIGN32(SDValue Op, SelectionDAG &DAG,
2313                                 bool HasExtractInsert) {
2314   EVT TyX = Op.getOperand(0).getValueType();
2315   EVT TyY = Op.getOperand(1).getValueType();
2316   SDLoc DL(Op);
2317   SDValue Const1 = DAG.getConstant(1, DL, MVT::i32);
2318   SDValue Const31 = DAG.getConstant(31, DL, MVT::i32);
2319   SDValue Res;
2320 
2321   // If operand is of type f64, extract the upper 32-bit. Otherwise, bitcast it
2322   // to i32.
2323   SDValue X = (TyX == MVT::f32) ?
2324     DAG.getNode(ISD::BITCAST, DL, MVT::i32, Op.getOperand(0)) :
2325     DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32, Op.getOperand(0),
2326                 Const1);
2327   SDValue Y = (TyY == MVT::f32) ?
2328     DAG.getNode(ISD::BITCAST, DL, MVT::i32, Op.getOperand(1)) :
2329     DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32, Op.getOperand(1),
2330                 Const1);
2331 
2332   if (HasExtractInsert) {
2333     // ext  E, Y, 31, 1  ; extract bit31 of Y
2334     // ins  X, E, 31, 1  ; insert extracted bit at bit31 of X
2335     SDValue E = DAG.getNode(MipsISD::Ext, DL, MVT::i32, Y, Const31, Const1);
2336     Res = DAG.getNode(MipsISD::Ins, DL, MVT::i32, E, Const31, Const1, X);
2337   } else {
2338     // sll SllX, X, 1
2339     // srl SrlX, SllX, 1
2340     // srl SrlY, Y, 31
2341     // sll SllY, SrlX, 31
2342     // or  Or, SrlX, SllY
2343     SDValue SllX = DAG.getNode(ISD::SHL, DL, MVT::i32, X, Const1);
2344     SDValue SrlX = DAG.getNode(ISD::SRL, DL, MVT::i32, SllX, Const1);
2345     SDValue SrlY = DAG.getNode(ISD::SRL, DL, MVT::i32, Y, Const31);
2346     SDValue SllY = DAG.getNode(ISD::SHL, DL, MVT::i32, SrlY, Const31);
2347     Res = DAG.getNode(ISD::OR, DL, MVT::i32, SrlX, SllY);
2348   }
2349 
2350   if (TyX == MVT::f32)
2351     return DAG.getNode(ISD::BITCAST, DL, Op.getOperand(0).getValueType(), Res);
2352 
2353   SDValue LowX = DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32,
2354                              Op.getOperand(0),
2355                              DAG.getConstant(0, DL, MVT::i32));
2356   return DAG.getNode(MipsISD::BuildPairF64, DL, MVT::f64, LowX, Res);
2357 }
2358 
2359 static SDValue lowerFCOPYSIGN64(SDValue Op, SelectionDAG &DAG,
2360                                 bool HasExtractInsert) {
2361   unsigned WidthX = Op.getOperand(0).getValueSizeInBits();
2362   unsigned WidthY = Op.getOperand(1).getValueSizeInBits();
2363   EVT TyX = MVT::getIntegerVT(WidthX), TyY = MVT::getIntegerVT(WidthY);
2364   SDLoc DL(Op);
2365   SDValue Const1 = DAG.getConstant(1, DL, MVT::i32);
2366 
2367   // Bitcast to integer nodes.
2368   SDValue X = DAG.getNode(ISD::BITCAST, DL, TyX, Op.getOperand(0));
2369   SDValue Y = DAG.getNode(ISD::BITCAST, DL, TyY, Op.getOperand(1));
2370 
2371   if (HasExtractInsert) {
2372     // ext  E, Y, width(Y) - 1, 1  ; extract bit width(Y)-1 of Y
2373     // ins  X, E, width(X) - 1, 1  ; insert extracted bit at bit width(X)-1 of X
2374     SDValue E = DAG.getNode(MipsISD::Ext, DL, TyY, Y,
2375                             DAG.getConstant(WidthY - 1, DL, MVT::i32), Const1);
2376 
2377     if (WidthX > WidthY)
2378       E = DAG.getNode(ISD::ZERO_EXTEND, DL, TyX, E);
2379     else if (WidthY > WidthX)
2380       E = DAG.getNode(ISD::TRUNCATE, DL, TyX, E);
2381 
2382     SDValue I = DAG.getNode(MipsISD::Ins, DL, TyX, E,
2383                             DAG.getConstant(WidthX - 1, DL, MVT::i32), Const1,
2384                             X);
2385     return DAG.getNode(ISD::BITCAST, DL, Op.getOperand(0).getValueType(), I);
2386   }
2387 
2388   // (d)sll SllX, X, 1
2389   // (d)srl SrlX, SllX, 1
2390   // (d)srl SrlY, Y, width(Y)-1
2391   // (d)sll SllY, SrlX, width(Y)-1
2392   // or     Or, SrlX, SllY
2393   SDValue SllX = DAG.getNode(ISD::SHL, DL, TyX, X, Const1);
2394   SDValue SrlX = DAG.getNode(ISD::SRL, DL, TyX, SllX, Const1);
2395   SDValue SrlY = DAG.getNode(ISD::SRL, DL, TyY, Y,
2396                              DAG.getConstant(WidthY - 1, DL, MVT::i32));
2397 
2398   if (WidthX > WidthY)
2399     SrlY = DAG.getNode(ISD::ZERO_EXTEND, DL, TyX, SrlY);
2400   else if (WidthY > WidthX)
2401     SrlY = DAG.getNode(ISD::TRUNCATE, DL, TyX, SrlY);
2402 
2403   SDValue SllY = DAG.getNode(ISD::SHL, DL, TyX, SrlY,
2404                              DAG.getConstant(WidthX - 1, DL, MVT::i32));
2405   SDValue Or = DAG.getNode(ISD::OR, DL, TyX, SrlX, SllY);
2406   return DAG.getNode(ISD::BITCAST, DL, Op.getOperand(0).getValueType(), Or);
2407 }
2408 
2409 SDValue
2410 MipsTargetLowering::lowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const {
2411   if (Subtarget.isGP64bit())
2412     return lowerFCOPYSIGN64(Op, DAG, Subtarget.hasExtractInsert());
2413 
2414   return lowerFCOPYSIGN32(Op, DAG, Subtarget.hasExtractInsert());
2415 }
2416 
2417 static SDValue lowerFABS32(SDValue Op, SelectionDAG &DAG,
2418                            bool HasExtractInsert) {
2419   SDLoc DL(Op);
2420   SDValue Res, Const1 = DAG.getConstant(1, DL, MVT::i32);
2421 
2422   // If operand is of type f64, extract the upper 32-bit. Otherwise, bitcast it
2423   // to i32.
2424   SDValue X = (Op.getValueType() == MVT::f32)
2425                   ? DAG.getNode(ISD::BITCAST, DL, MVT::i32, Op.getOperand(0))
2426                   : DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32,
2427                                 Op.getOperand(0), Const1);
2428 
2429   // Clear MSB.
2430   if (HasExtractInsert)
2431     Res = DAG.getNode(MipsISD::Ins, DL, MVT::i32,
2432                       DAG.getRegister(Mips::ZERO, MVT::i32),
2433                       DAG.getConstant(31, DL, MVT::i32), Const1, X);
2434   else {
2435     // TODO: Provide DAG patterns which transform (and x, cst)
2436     // back to a (shl (srl x (clz cst)) (clz cst)) sequence.
2437     SDValue SllX = DAG.getNode(ISD::SHL, DL, MVT::i32, X, Const1);
2438     Res = DAG.getNode(ISD::SRL, DL, MVT::i32, SllX, Const1);
2439   }
2440 
2441   if (Op.getValueType() == MVT::f32)
2442     return DAG.getNode(ISD::BITCAST, DL, MVT::f32, Res);
2443 
2444   // FIXME: For mips32r2, the sequence of (BuildPairF64 (ins (ExtractElementF64
2445   // Op 1), $zero, 31 1) (ExtractElementF64 Op 0)) and the Op has one use, we
2446   // should be able to drop the usage of mfc1/mtc1 and rewrite the register in
2447   // place.
2448   SDValue LowX =
2449       DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32, Op.getOperand(0),
2450                   DAG.getConstant(0, DL, MVT::i32));
2451   return DAG.getNode(MipsISD::BuildPairF64, DL, MVT::f64, LowX, Res);
2452 }
2453 
2454 static SDValue lowerFABS64(SDValue Op, SelectionDAG &DAG,
2455                            bool HasExtractInsert) {
2456   SDLoc DL(Op);
2457   SDValue Res, Const1 = DAG.getConstant(1, DL, MVT::i32);
2458 
2459   // Bitcast to integer node.
2460   SDValue X = DAG.getNode(ISD::BITCAST, DL, MVT::i64, Op.getOperand(0));
2461 
2462   // Clear MSB.
2463   if (HasExtractInsert)
2464     Res = DAG.getNode(MipsISD::Ins, DL, MVT::i64,
2465                       DAG.getRegister(Mips::ZERO_64, MVT::i64),
2466                       DAG.getConstant(63, DL, MVT::i32), Const1, X);
2467   else {
2468     SDValue SllX = DAG.getNode(ISD::SHL, DL, MVT::i64, X, Const1);
2469     Res = DAG.getNode(ISD::SRL, DL, MVT::i64, SllX, Const1);
2470   }
2471 
2472   return DAG.getNode(ISD::BITCAST, DL, MVT::f64, Res);
2473 }
2474 
2475 SDValue MipsTargetLowering::lowerFABS(SDValue Op, SelectionDAG &DAG) const {
2476   if ((ABI.IsN32() || ABI.IsN64()) && (Op.getValueType() == MVT::f64))
2477     return lowerFABS64(Op, DAG, Subtarget.hasExtractInsert());
2478 
2479   return lowerFABS32(Op, DAG, Subtarget.hasExtractInsert());
2480 }
2481 
2482 SDValue MipsTargetLowering::
2483 lowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
2484   // check the depth
2485   if (cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() != 0) {
2486     DAG.getContext()->emitError(
2487         "return address can be determined only for current frame");
2488     return SDValue();
2489   }
2490 
2491   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
2492   MFI.setFrameAddressIsTaken(true);
2493   EVT VT = Op.getValueType();
2494   SDLoc DL(Op);
2495   SDValue FrameAddr = DAG.getCopyFromReg(
2496       DAG.getEntryNode(), DL, ABI.IsN64() ? Mips::FP_64 : Mips::FP, VT);
2497   return FrameAddr;
2498 }
2499 
2500 SDValue MipsTargetLowering::lowerRETURNADDR(SDValue Op,
2501                                             SelectionDAG &DAG) const {
2502   if (verifyReturnAddressArgumentIsConstant(Op, DAG))
2503     return SDValue();
2504 
2505   // check the depth
2506   if (cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() != 0) {
2507     DAG.getContext()->emitError(
2508         "return address can be determined only for current frame");
2509     return SDValue();
2510   }
2511 
2512   MachineFunction &MF = DAG.getMachineFunction();
2513   MachineFrameInfo &MFI = MF.getFrameInfo();
2514   MVT VT = Op.getSimpleValueType();
2515   unsigned RA = ABI.IsN64() ? Mips::RA_64 : Mips::RA;
2516   MFI.setReturnAddressIsTaken(true);
2517 
2518   // Return RA, which contains the return address. Mark it an implicit live-in.
2519   Register Reg = MF.addLiveIn(RA, getRegClassFor(VT));
2520   return DAG.getCopyFromReg(DAG.getEntryNode(), SDLoc(Op), Reg, VT);
2521 }
2522 
2523 // An EH_RETURN is the result of lowering llvm.eh.return which in turn is
2524 // generated from __builtin_eh_return (offset, handler)
2525 // The effect of this is to adjust the stack pointer by "offset"
2526 // and then branch to "handler".
2527 SDValue MipsTargetLowering::lowerEH_RETURN(SDValue Op, SelectionDAG &DAG)
2528                                                                      const {
2529   MachineFunction &MF = DAG.getMachineFunction();
2530   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
2531 
2532   MipsFI->setCallsEhReturn();
2533   SDValue Chain     = Op.getOperand(0);
2534   SDValue Offset    = Op.getOperand(1);
2535   SDValue Handler   = Op.getOperand(2);
2536   SDLoc DL(Op);
2537   EVT Ty = ABI.IsN64() ? MVT::i64 : MVT::i32;
2538 
2539   // Store stack offset in V1, store jump target in V0. Glue CopyToReg and
2540   // EH_RETURN nodes, so that instructions are emitted back-to-back.
2541   unsigned OffsetReg = ABI.IsN64() ? Mips::V1_64 : Mips::V1;
2542   unsigned AddrReg = ABI.IsN64() ? Mips::V0_64 : Mips::V0;
2543   Chain = DAG.getCopyToReg(Chain, DL, OffsetReg, Offset, SDValue());
2544   Chain = DAG.getCopyToReg(Chain, DL, AddrReg, Handler, Chain.getValue(1));
2545   return DAG.getNode(MipsISD::EH_RETURN, DL, MVT::Other, Chain,
2546                      DAG.getRegister(OffsetReg, Ty),
2547                      DAG.getRegister(AddrReg, getPointerTy(MF.getDataLayout())),
2548                      Chain.getValue(1));
2549 }
2550 
2551 SDValue MipsTargetLowering::lowerATOMIC_FENCE(SDValue Op,
2552                                               SelectionDAG &DAG) const {
2553   // FIXME: Need pseudo-fence for 'singlethread' fences
2554   // FIXME: Set SType for weaker fences where supported/appropriate.
2555   unsigned SType = 0;
2556   SDLoc DL(Op);
2557   return DAG.getNode(MipsISD::Sync, DL, MVT::Other, Op.getOperand(0),
2558                      DAG.getConstant(SType, DL, MVT::i32));
2559 }
2560 
2561 SDValue MipsTargetLowering::lowerShiftLeftParts(SDValue Op,
2562                                                 SelectionDAG &DAG) const {
2563   SDLoc DL(Op);
2564   MVT VT = Subtarget.isGP64bit() ? MVT::i64 : MVT::i32;
2565 
2566   SDValue Lo = Op.getOperand(0), Hi = Op.getOperand(1);
2567   SDValue Shamt = Op.getOperand(2);
2568   // if shamt < (VT.bits):
2569   //  lo = (shl lo, shamt)
2570   //  hi = (or (shl hi, shamt) (srl (srl lo, 1), ~shamt))
2571   // else:
2572   //  lo = 0
2573   //  hi = (shl lo, shamt[4:0])
2574   SDValue Not = DAG.getNode(ISD::XOR, DL, MVT::i32, Shamt,
2575                             DAG.getConstant(-1, DL, MVT::i32));
2576   SDValue ShiftRight1Lo = DAG.getNode(ISD::SRL, DL, VT, Lo,
2577                                       DAG.getConstant(1, DL, VT));
2578   SDValue ShiftRightLo = DAG.getNode(ISD::SRL, DL, VT, ShiftRight1Lo, Not);
2579   SDValue ShiftLeftHi = DAG.getNode(ISD::SHL, DL, VT, Hi, Shamt);
2580   SDValue Or = DAG.getNode(ISD::OR, DL, VT, ShiftLeftHi, ShiftRightLo);
2581   SDValue ShiftLeftLo = DAG.getNode(ISD::SHL, DL, VT, Lo, Shamt);
2582   SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
2583                              DAG.getConstant(VT.getSizeInBits(), DL, MVT::i32));
2584   Lo = DAG.getNode(ISD::SELECT, DL, VT, Cond,
2585                    DAG.getConstant(0, DL, VT), ShiftLeftLo);
2586   Hi = DAG.getNode(ISD::SELECT, DL, VT, Cond, ShiftLeftLo, Or);
2587 
2588   SDValue Ops[2] = {Lo, Hi};
2589   return DAG.getMergeValues(Ops, DL);
2590 }
2591 
2592 SDValue MipsTargetLowering::lowerShiftRightParts(SDValue Op, SelectionDAG &DAG,
2593                                                  bool IsSRA) const {
2594   SDLoc DL(Op);
2595   SDValue Lo = Op.getOperand(0), Hi = Op.getOperand(1);
2596   SDValue Shamt = Op.getOperand(2);
2597   MVT VT = Subtarget.isGP64bit() ? MVT::i64 : MVT::i32;
2598 
2599   // if shamt < (VT.bits):
2600   //  lo = (or (shl (shl hi, 1), ~shamt) (srl lo, shamt))
2601   //  if isSRA:
2602   //    hi = (sra hi, shamt)
2603   //  else:
2604   //    hi = (srl hi, shamt)
2605   // else:
2606   //  if isSRA:
2607   //   lo = (sra hi, shamt[4:0])
2608   //   hi = (sra hi, 31)
2609   //  else:
2610   //   lo = (srl hi, shamt[4:0])
2611   //   hi = 0
2612   SDValue Not = DAG.getNode(ISD::XOR, DL, MVT::i32, Shamt,
2613                             DAG.getConstant(-1, DL, MVT::i32));
2614   SDValue ShiftLeft1Hi = DAG.getNode(ISD::SHL, DL, VT, Hi,
2615                                      DAG.getConstant(1, DL, VT));
2616   SDValue ShiftLeftHi = DAG.getNode(ISD::SHL, DL, VT, ShiftLeft1Hi, Not);
2617   SDValue ShiftRightLo = DAG.getNode(ISD::SRL, DL, VT, Lo, Shamt);
2618   SDValue Or = DAG.getNode(ISD::OR, DL, VT, ShiftLeftHi, ShiftRightLo);
2619   SDValue ShiftRightHi = DAG.getNode(IsSRA ? ISD::SRA : ISD::SRL,
2620                                      DL, VT, Hi, Shamt);
2621   SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
2622                              DAG.getConstant(VT.getSizeInBits(), DL, MVT::i32));
2623   SDValue Ext = DAG.getNode(ISD::SRA, DL, VT, Hi,
2624                             DAG.getConstant(VT.getSizeInBits() - 1, DL, VT));
2625 
2626   if (!(Subtarget.hasMips4() || Subtarget.hasMips32())) {
2627     SDVTList VTList = DAG.getVTList(VT, VT);
2628     return DAG.getNode(Subtarget.isGP64bit() ? Mips::PseudoD_SELECT_I64
2629                                              : Mips::PseudoD_SELECT_I,
2630                        DL, VTList, Cond, ShiftRightHi,
2631                        IsSRA ? Ext : DAG.getConstant(0, DL, VT), Or,
2632                        ShiftRightHi);
2633   }
2634 
2635   Lo = DAG.getNode(ISD::SELECT, DL, VT, Cond, ShiftRightHi, Or);
2636   Hi = DAG.getNode(ISD::SELECT, DL, VT, Cond,
2637                    IsSRA ? Ext : DAG.getConstant(0, DL, VT), ShiftRightHi);
2638 
2639   SDValue Ops[2] = {Lo, Hi};
2640   return DAG.getMergeValues(Ops, DL);
2641 }
2642 
2643 static SDValue createLoadLR(unsigned Opc, SelectionDAG &DAG, LoadSDNode *LD,
2644                             SDValue Chain, SDValue Src, unsigned Offset) {
2645   SDValue Ptr = LD->getBasePtr();
2646   EVT VT = LD->getValueType(0), MemVT = LD->getMemoryVT();
2647   EVT BasePtrVT = Ptr.getValueType();
2648   SDLoc DL(LD);
2649   SDVTList VTList = DAG.getVTList(VT, MVT::Other);
2650 
2651   if (Offset)
2652     Ptr = DAG.getNode(ISD::ADD, DL, BasePtrVT, Ptr,
2653                       DAG.getConstant(Offset, DL, BasePtrVT));
2654 
2655   SDValue Ops[] = { Chain, Ptr, Src };
2656   return DAG.getMemIntrinsicNode(Opc, DL, VTList, Ops, MemVT,
2657                                  LD->getMemOperand());
2658 }
2659 
2660 // Expand an unaligned 32 or 64-bit integer load node.
2661 SDValue MipsTargetLowering::lowerLOAD(SDValue Op, SelectionDAG &DAG) const {
2662   LoadSDNode *LD = cast<LoadSDNode>(Op);
2663   EVT MemVT = LD->getMemoryVT();
2664 
2665   if (Subtarget.systemSupportsUnalignedAccess())
2666     return Op;
2667 
2668   // Return if load is aligned or if MemVT is neither i32 nor i64.
2669   if ((LD->getAlignment() >= MemVT.getSizeInBits() / 8) ||
2670       ((MemVT != MVT::i32) && (MemVT != MVT::i64)))
2671     return SDValue();
2672 
2673   bool IsLittle = Subtarget.isLittle();
2674   EVT VT = Op.getValueType();
2675   ISD::LoadExtType ExtType = LD->getExtensionType();
2676   SDValue Chain = LD->getChain(), Undef = DAG.getUNDEF(VT);
2677 
2678   assert((VT == MVT::i32) || (VT == MVT::i64));
2679 
2680   // Expand
2681   //  (set dst, (i64 (load baseptr)))
2682   // to
2683   //  (set tmp, (ldl (add baseptr, 7), undef))
2684   //  (set dst, (ldr baseptr, tmp))
2685   if ((VT == MVT::i64) && (ExtType == ISD::NON_EXTLOAD)) {
2686     SDValue LDL = createLoadLR(MipsISD::LDL, DAG, LD, Chain, Undef,
2687                                IsLittle ? 7 : 0);
2688     return createLoadLR(MipsISD::LDR, DAG, LD, LDL.getValue(1), LDL,
2689                         IsLittle ? 0 : 7);
2690   }
2691 
2692   SDValue LWL = createLoadLR(MipsISD::LWL, DAG, LD, Chain, Undef,
2693                              IsLittle ? 3 : 0);
2694   SDValue LWR = createLoadLR(MipsISD::LWR, DAG, LD, LWL.getValue(1), LWL,
2695                              IsLittle ? 0 : 3);
2696 
2697   // Expand
2698   //  (set dst, (i32 (load baseptr))) or
2699   //  (set dst, (i64 (sextload baseptr))) or
2700   //  (set dst, (i64 (extload baseptr)))
2701   // to
2702   //  (set tmp, (lwl (add baseptr, 3), undef))
2703   //  (set dst, (lwr baseptr, tmp))
2704   if ((VT == MVT::i32) || (ExtType == ISD::SEXTLOAD) ||
2705       (ExtType == ISD::EXTLOAD))
2706     return LWR;
2707 
2708   assert((VT == MVT::i64) && (ExtType == ISD::ZEXTLOAD));
2709 
2710   // Expand
2711   //  (set dst, (i64 (zextload baseptr)))
2712   // to
2713   //  (set tmp0, (lwl (add baseptr, 3), undef))
2714   //  (set tmp1, (lwr baseptr, tmp0))
2715   //  (set tmp2, (shl tmp1, 32))
2716   //  (set dst, (srl tmp2, 32))
2717   SDLoc DL(LD);
2718   SDValue Const32 = DAG.getConstant(32, DL, MVT::i32);
2719   SDValue SLL = DAG.getNode(ISD::SHL, DL, MVT::i64, LWR, Const32);
2720   SDValue SRL = DAG.getNode(ISD::SRL, DL, MVT::i64, SLL, Const32);
2721   SDValue Ops[] = { SRL, LWR.getValue(1) };
2722   return DAG.getMergeValues(Ops, DL);
2723 }
2724 
2725 static SDValue createStoreLR(unsigned Opc, SelectionDAG &DAG, StoreSDNode *SD,
2726                              SDValue Chain, unsigned Offset) {
2727   SDValue Ptr = SD->getBasePtr(), Value = SD->getValue();
2728   EVT MemVT = SD->getMemoryVT(), BasePtrVT = Ptr.getValueType();
2729   SDLoc DL(SD);
2730   SDVTList VTList = DAG.getVTList(MVT::Other);
2731 
2732   if (Offset)
2733     Ptr = DAG.getNode(ISD::ADD, DL, BasePtrVT, Ptr,
2734                       DAG.getConstant(Offset, DL, BasePtrVT));
2735 
2736   SDValue Ops[] = { Chain, Value, Ptr };
2737   return DAG.getMemIntrinsicNode(Opc, DL, VTList, Ops, MemVT,
2738                                  SD->getMemOperand());
2739 }
2740 
2741 // Expand an unaligned 32 or 64-bit integer store node.
2742 static SDValue lowerUnalignedIntStore(StoreSDNode *SD, SelectionDAG &DAG,
2743                                       bool IsLittle) {
2744   SDValue Value = SD->getValue(), Chain = SD->getChain();
2745   EVT VT = Value.getValueType();
2746 
2747   // Expand
2748   //  (store val, baseptr) or
2749   //  (truncstore val, baseptr)
2750   // to
2751   //  (swl val, (add baseptr, 3))
2752   //  (swr val, baseptr)
2753   if ((VT == MVT::i32) || SD->isTruncatingStore()) {
2754     SDValue SWL = createStoreLR(MipsISD::SWL, DAG, SD, Chain,
2755                                 IsLittle ? 3 : 0);
2756     return createStoreLR(MipsISD::SWR, DAG, SD, SWL, IsLittle ? 0 : 3);
2757   }
2758 
2759   assert(VT == MVT::i64);
2760 
2761   // Expand
2762   //  (store val, baseptr)
2763   // to
2764   //  (sdl val, (add baseptr, 7))
2765   //  (sdr val, baseptr)
2766   SDValue SDL = createStoreLR(MipsISD::SDL, DAG, SD, Chain, IsLittle ? 7 : 0);
2767   return createStoreLR(MipsISD::SDR, DAG, SD, SDL, IsLittle ? 0 : 7);
2768 }
2769 
2770 // Lower (store (fp_to_sint $fp) $ptr) to (store (TruncIntFP $fp), $ptr).
2771 static SDValue lowerFP_TO_SINT_STORE(StoreSDNode *SD, SelectionDAG &DAG,
2772                                      bool SingleFloat) {
2773   SDValue Val = SD->getValue();
2774 
2775   if (Val.getOpcode() != ISD::FP_TO_SINT ||
2776       (Val.getValueSizeInBits() > 32 && SingleFloat))
2777     return SDValue();
2778 
2779   EVT FPTy = EVT::getFloatingPointVT(Val.getValueSizeInBits());
2780   SDValue Tr = DAG.getNode(MipsISD::TruncIntFP, SDLoc(Val), FPTy,
2781                            Val.getOperand(0));
2782   return DAG.getStore(SD->getChain(), SDLoc(SD), Tr, SD->getBasePtr(),
2783                       SD->getPointerInfo(), SD->getAlignment(),
2784                       SD->getMemOperand()->getFlags());
2785 }
2786 
2787 SDValue MipsTargetLowering::lowerSTORE(SDValue Op, SelectionDAG &DAG) const {
2788   StoreSDNode *SD = cast<StoreSDNode>(Op);
2789   EVT MemVT = SD->getMemoryVT();
2790 
2791   // Lower unaligned integer stores.
2792   if (!Subtarget.systemSupportsUnalignedAccess() &&
2793       (SD->getAlignment() < MemVT.getSizeInBits() / 8) &&
2794       ((MemVT == MVT::i32) || (MemVT == MVT::i64)))
2795     return lowerUnalignedIntStore(SD, DAG, Subtarget.isLittle());
2796 
2797   return lowerFP_TO_SINT_STORE(SD, DAG, Subtarget.isSingleFloat());
2798 }
2799 
2800 SDValue MipsTargetLowering::lowerEH_DWARF_CFA(SDValue Op,
2801                                               SelectionDAG &DAG) const {
2802 
2803   // Return a fixed StackObject with offset 0 which points to the old stack
2804   // pointer.
2805   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
2806   EVT ValTy = Op->getValueType(0);
2807   int FI = MFI.CreateFixedObject(Op.getValueSizeInBits() / 8, 0, false);
2808   return DAG.getFrameIndex(FI, ValTy);
2809 }
2810 
2811 SDValue MipsTargetLowering::lowerFP_TO_SINT(SDValue Op,
2812                                             SelectionDAG &DAG) const {
2813   if (Op.getValueSizeInBits() > 32 && Subtarget.isSingleFloat())
2814     return SDValue();
2815 
2816   EVT FPTy = EVT::getFloatingPointVT(Op.getValueSizeInBits());
2817   SDValue Trunc = DAG.getNode(MipsISD::TruncIntFP, SDLoc(Op), FPTy,
2818                               Op.getOperand(0));
2819   return DAG.getNode(ISD::BITCAST, SDLoc(Op), Op.getValueType(), Trunc);
2820 }
2821 
2822 //===----------------------------------------------------------------------===//
2823 //                      Calling Convention Implementation
2824 //===----------------------------------------------------------------------===//
2825 
2826 //===----------------------------------------------------------------------===//
2827 // TODO: Implement a generic logic using tblgen that can support this.
2828 // Mips O32 ABI rules:
2829 // ---
2830 // i32 - Passed in A0, A1, A2, A3 and stack
2831 // f32 - Only passed in f32 registers if no int reg has been used yet to hold
2832 //       an argument. Otherwise, passed in A1, A2, A3 and stack.
2833 // f64 - Only passed in two aliased f32 registers if no int reg has been used
2834 //       yet to hold an argument. Otherwise, use A2, A3 and stack. If A1 is
2835 //       not used, it must be shadowed. If only A3 is available, shadow it and
2836 //       go to stack.
2837 // vXiX - Received as scalarized i32s, passed in A0 - A3 and the stack.
2838 // vXf32 - Passed in either a pair of registers {A0, A1}, {A2, A3} or {A0 - A3}
2839 //         with the remainder spilled to the stack.
2840 // vXf64 - Passed in either {A0, A1, A2, A3} or {A2, A3} and in both cases
2841 //         spilling the remainder to the stack.
2842 //
2843 //  For vararg functions, all arguments are passed in A0, A1, A2, A3 and stack.
2844 //===----------------------------------------------------------------------===//
2845 
2846 static bool CC_MipsO32(unsigned ValNo, MVT ValVT, MVT LocVT,
2847                        CCValAssign::LocInfo LocInfo, ISD::ArgFlagsTy ArgFlags,
2848                        CCState &State, ArrayRef<MCPhysReg> F64Regs) {
2849   const MipsSubtarget &Subtarget = static_cast<const MipsSubtarget &>(
2850       State.getMachineFunction().getSubtarget());
2851 
2852   static const MCPhysReg IntRegs[] = { Mips::A0, Mips::A1, Mips::A2, Mips::A3 };
2853 
2854   const MipsCCState * MipsState = static_cast<MipsCCState *>(&State);
2855 
2856   static const MCPhysReg F32Regs[] = { Mips::F12, Mips::F14 };
2857 
2858   static const MCPhysReg FloatVectorIntRegs[] = { Mips::A0, Mips::A2 };
2859 
2860   // Do not process byval args here.
2861   if (ArgFlags.isByVal())
2862     return true;
2863 
2864   // Promote i8 and i16
2865   if (ArgFlags.isInReg() && !Subtarget.isLittle()) {
2866     if (LocVT == MVT::i8 || LocVT == MVT::i16 || LocVT == MVT::i32) {
2867       LocVT = MVT::i32;
2868       if (ArgFlags.isSExt())
2869         LocInfo = CCValAssign::SExtUpper;
2870       else if (ArgFlags.isZExt())
2871         LocInfo = CCValAssign::ZExtUpper;
2872       else
2873         LocInfo = CCValAssign::AExtUpper;
2874     }
2875   }
2876 
2877   // Promote i8 and i16
2878   if (LocVT == MVT::i8 || LocVT == MVT::i16) {
2879     LocVT = MVT::i32;
2880     if (ArgFlags.isSExt())
2881       LocInfo = CCValAssign::SExt;
2882     else if (ArgFlags.isZExt())
2883       LocInfo = CCValAssign::ZExt;
2884     else
2885       LocInfo = CCValAssign::AExt;
2886   }
2887 
2888   unsigned Reg;
2889 
2890   // f32 and f64 are allocated in A0, A1, A2, A3 when either of the following
2891   // is true: function is vararg, argument is 3rd or higher, there is previous
2892   // argument which is not f32 or f64.
2893   bool AllocateFloatsInIntReg = State.isVarArg() || ValNo > 1 ||
2894                                 State.getFirstUnallocated(F32Regs) != ValNo;
2895   Align OrigAlign = ArgFlags.getNonZeroOrigAlign();
2896   bool isI64 = (ValVT == MVT::i32 && OrigAlign == Align(8));
2897   bool isVectorFloat = MipsState->WasOriginalArgVectorFloat(ValNo);
2898 
2899   // The MIPS vector ABI for floats passes them in a pair of registers
2900   if (ValVT == MVT::i32 && isVectorFloat) {
2901     // This is the start of an vector that was scalarized into an unknown number
2902     // of components. It doesn't matter how many there are. Allocate one of the
2903     // notional 8 byte aligned registers which map onto the argument stack, and
2904     // shadow the register lost to alignment requirements.
2905     if (ArgFlags.isSplit()) {
2906       Reg = State.AllocateReg(FloatVectorIntRegs);
2907       if (Reg == Mips::A2)
2908         State.AllocateReg(Mips::A1);
2909       else if (Reg == 0)
2910         State.AllocateReg(Mips::A3);
2911     } else {
2912       // If we're an intermediate component of the split, we can just attempt to
2913       // allocate a register directly.
2914       Reg = State.AllocateReg(IntRegs);
2915     }
2916   } else if (ValVT == MVT::i32 ||
2917              (ValVT == MVT::f32 && AllocateFloatsInIntReg)) {
2918     Reg = State.AllocateReg(IntRegs);
2919     // If this is the first part of an i64 arg,
2920     // the allocated register must be either A0 or A2.
2921     if (isI64 && (Reg == Mips::A1 || Reg == Mips::A3))
2922       Reg = State.AllocateReg(IntRegs);
2923     LocVT = MVT::i32;
2924   } else if (ValVT == MVT::f64 && AllocateFloatsInIntReg) {
2925     LocVT = MVT::i32;
2926 
2927     // Allocate int register and shadow next int register. If first
2928     // available register is Mips::A1 or Mips::A3, shadow it too.
2929     Reg = State.AllocateReg(IntRegs);
2930     if (Reg == Mips::A1 || Reg == Mips::A3)
2931       Reg = State.AllocateReg(IntRegs);
2932 
2933     if (Reg) {
2934       State.addLoc(
2935           CCValAssign::getCustomReg(ValNo, ValVT, Reg, LocVT, LocInfo));
2936       MCRegister HiReg = State.AllocateReg(IntRegs);
2937       assert(HiReg);
2938       State.addLoc(
2939           CCValAssign::getCustomReg(ValNo, ValVT, HiReg, LocVT, LocInfo));
2940       return false;
2941     }
2942   } else if (ValVT.isFloatingPoint() && !AllocateFloatsInIntReg) {
2943     // we are guaranteed to find an available float register
2944     if (ValVT == MVT::f32) {
2945       Reg = State.AllocateReg(F32Regs);
2946       // Shadow int register
2947       State.AllocateReg(IntRegs);
2948     } else {
2949       Reg = State.AllocateReg(F64Regs);
2950       // Shadow int registers
2951       unsigned Reg2 = State.AllocateReg(IntRegs);
2952       if (Reg2 == Mips::A1 || Reg2 == Mips::A3)
2953         State.AllocateReg(IntRegs);
2954       State.AllocateReg(IntRegs);
2955     }
2956   } else
2957     llvm_unreachable("Cannot handle this ValVT.");
2958 
2959   if (!Reg) {
2960     unsigned Offset = State.AllocateStack(ValVT.getStoreSize(), OrigAlign);
2961     State.addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
2962   } else
2963     State.addLoc(CCValAssign::getReg(ValNo, ValVT, Reg, LocVT, LocInfo));
2964 
2965   return false;
2966 }
2967 
2968 static bool CC_MipsO32_FP32(unsigned ValNo, MVT ValVT,
2969                             MVT LocVT, CCValAssign::LocInfo LocInfo,
2970                             ISD::ArgFlagsTy ArgFlags, CCState &State) {
2971   static const MCPhysReg F64Regs[] = { Mips::D6, Mips::D7 };
2972 
2973   return CC_MipsO32(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State, F64Regs);
2974 }
2975 
2976 static bool CC_MipsO32_FP64(unsigned ValNo, MVT ValVT,
2977                             MVT LocVT, CCValAssign::LocInfo LocInfo,
2978                             ISD::ArgFlagsTy ArgFlags, CCState &State) {
2979   static const MCPhysReg F64Regs[] = { Mips::D12_64, Mips::D14_64 };
2980 
2981   return CC_MipsO32(ValNo, ValVT, LocVT, LocInfo, ArgFlags, State, F64Regs);
2982 }
2983 
2984 static bool CC_MipsO32(unsigned ValNo, MVT ValVT, MVT LocVT,
2985                        CCValAssign::LocInfo LocInfo, ISD::ArgFlagsTy ArgFlags,
2986                        CCState &State) LLVM_ATTRIBUTE_UNUSED;
2987 
2988 #include "MipsGenCallingConv.inc"
2989 
2990  CCAssignFn *MipsTargetLowering::CCAssignFnForCall() const{
2991    return CC_Mips_FixedArg;
2992  }
2993 
2994  CCAssignFn *MipsTargetLowering::CCAssignFnForReturn() const{
2995    return RetCC_Mips;
2996  }
2997 //===----------------------------------------------------------------------===//
2998 //                  Call Calling Convention Implementation
2999 //===----------------------------------------------------------------------===//
3000 
3001 SDValue MipsTargetLowering::passArgOnStack(SDValue StackPtr, unsigned Offset,
3002                                            SDValue Chain, SDValue Arg,
3003                                            const SDLoc &DL, bool IsTailCall,
3004                                            SelectionDAG &DAG) const {
3005   if (!IsTailCall) {
3006     SDValue PtrOff =
3007         DAG.getNode(ISD::ADD, DL, getPointerTy(DAG.getDataLayout()), StackPtr,
3008                     DAG.getIntPtrConstant(Offset, DL));
3009     return DAG.getStore(Chain, DL, Arg, PtrOff, MachinePointerInfo());
3010   }
3011 
3012   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
3013   int FI = MFI.CreateFixedObject(Arg.getValueSizeInBits() / 8, Offset, false);
3014   SDValue FIN = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
3015   return DAG.getStore(Chain, DL, Arg, FIN, MachinePointerInfo(), MaybeAlign(),
3016                       MachineMemOperand::MOVolatile);
3017 }
3018 
3019 void MipsTargetLowering::
3020 getOpndList(SmallVectorImpl<SDValue> &Ops,
3021             std::deque<std::pair<unsigned, SDValue>> &RegsToPass,
3022             bool IsPICCall, bool GlobalOrExternal, bool InternalLinkage,
3023             bool IsCallReloc, CallLoweringInfo &CLI, SDValue Callee,
3024             SDValue Chain) const {
3025   // Insert node "GP copy globalreg" before call to function.
3026   //
3027   // R_MIPS_CALL* operators (emitted when non-internal functions are called
3028   // in PIC mode) allow symbols to be resolved via lazy binding.
3029   // The lazy binding stub requires GP to point to the GOT.
3030   // Note that we don't need GP to point to the GOT for indirect calls
3031   // (when R_MIPS_CALL* is not used for the call) because Mips linker generates
3032   // lazy binding stub for a function only when R_MIPS_CALL* are the only relocs
3033   // used for the function (that is, Mips linker doesn't generate lazy binding
3034   // stub for a function whose address is taken in the program).
3035   if (IsPICCall && !InternalLinkage && IsCallReloc) {
3036     unsigned GPReg = ABI.IsN64() ? Mips::GP_64 : Mips::GP;
3037     EVT Ty = ABI.IsN64() ? MVT::i64 : MVT::i32;
3038     RegsToPass.push_back(std::make_pair(GPReg, getGlobalReg(CLI.DAG, Ty)));
3039   }
3040 
3041   // Build a sequence of copy-to-reg nodes chained together with token
3042   // chain and flag operands which copy the outgoing args into registers.
3043   // The InFlag in necessary since all emitted instructions must be
3044   // stuck together.
3045   SDValue InFlag;
3046 
3047   for (auto &R : RegsToPass) {
3048     Chain = CLI.DAG.getCopyToReg(Chain, CLI.DL, R.first, R.second, InFlag);
3049     InFlag = Chain.getValue(1);
3050   }
3051 
3052   // Add argument registers to the end of the list so that they are
3053   // known live into the call.
3054   for (auto &R : RegsToPass)
3055     Ops.push_back(CLI.DAG.getRegister(R.first, R.second.getValueType()));
3056 
3057   // Add a register mask operand representing the call-preserved registers.
3058   const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
3059   const uint32_t *Mask =
3060       TRI->getCallPreservedMask(CLI.DAG.getMachineFunction(), CLI.CallConv);
3061   assert(Mask && "Missing call preserved mask for calling convention");
3062   if (Subtarget.inMips16HardFloat()) {
3063     if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(CLI.Callee)) {
3064       StringRef Sym = G->getGlobal()->getName();
3065       Function *F = G->getGlobal()->getParent()->getFunction(Sym);
3066       if (F && F->hasFnAttribute("__Mips16RetHelper")) {
3067         Mask = MipsRegisterInfo::getMips16RetHelperMask();
3068       }
3069     }
3070   }
3071   Ops.push_back(CLI.DAG.getRegisterMask(Mask));
3072 
3073   if (InFlag.getNode())
3074     Ops.push_back(InFlag);
3075 }
3076 
3077 void MipsTargetLowering::AdjustInstrPostInstrSelection(MachineInstr &MI,
3078                                                        SDNode *Node) const {
3079   switch (MI.getOpcode()) {
3080     default:
3081       return;
3082     case Mips::JALR:
3083     case Mips::JALRPseudo:
3084     case Mips::JALR64:
3085     case Mips::JALR64Pseudo:
3086     case Mips::JALR16_MM:
3087     case Mips::JALRC16_MMR6:
3088     case Mips::TAILCALLREG:
3089     case Mips::TAILCALLREG64:
3090     case Mips::TAILCALLR6REG:
3091     case Mips::TAILCALL64R6REG:
3092     case Mips::TAILCALLREG_MM:
3093     case Mips::TAILCALLREG_MMR6: {
3094       if (!EmitJalrReloc ||
3095           Subtarget.inMips16Mode() ||
3096           !isPositionIndependent() ||
3097           Node->getNumOperands() < 1 ||
3098           Node->getOperand(0).getNumOperands() < 2) {
3099         return;
3100       }
3101       // We are after the callee address, set by LowerCall().
3102       // If added to MI, asm printer will emit .reloc R_MIPS_JALR for the
3103       // symbol.
3104       const SDValue TargetAddr = Node->getOperand(0).getOperand(1);
3105       StringRef Sym;
3106       if (const GlobalAddressSDNode *G =
3107               dyn_cast_or_null<const GlobalAddressSDNode>(TargetAddr)) {
3108         // We must not emit the R_MIPS_JALR relocation against data symbols
3109         // since this will cause run-time crashes if the linker replaces the
3110         // call instruction with a relative branch to the data symbol.
3111         if (!isa<Function>(G->getGlobal())) {
3112           LLVM_DEBUG(dbgs() << "Not adding R_MIPS_JALR against data symbol "
3113                             << G->getGlobal()->getName() << "\n");
3114           return;
3115         }
3116         Sym = G->getGlobal()->getName();
3117       }
3118       else if (const ExternalSymbolSDNode *ES =
3119                    dyn_cast_or_null<const ExternalSymbolSDNode>(TargetAddr)) {
3120         Sym = ES->getSymbol();
3121       }
3122 
3123       if (Sym.empty())
3124         return;
3125 
3126       MachineFunction *MF = MI.getParent()->getParent();
3127       MCSymbol *S = MF->getContext().getOrCreateSymbol(Sym);
3128       LLVM_DEBUG(dbgs() << "Adding R_MIPS_JALR against " << Sym << "\n");
3129       MI.addOperand(MachineOperand::CreateMCSymbol(S, MipsII::MO_JALR));
3130     }
3131   }
3132 }
3133 
3134 /// LowerCall - functions arguments are copied from virtual regs to
3135 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
3136 SDValue
3137 MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
3138                               SmallVectorImpl<SDValue> &InVals) const {
3139   SelectionDAG &DAG                     = CLI.DAG;
3140   SDLoc DL                              = CLI.DL;
3141   SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
3142   SmallVectorImpl<SDValue> &OutVals     = CLI.OutVals;
3143   SmallVectorImpl<ISD::InputArg> &Ins   = CLI.Ins;
3144   SDValue Chain                         = CLI.Chain;
3145   SDValue Callee                        = CLI.Callee;
3146   bool &IsTailCall                      = CLI.IsTailCall;
3147   CallingConv::ID CallConv              = CLI.CallConv;
3148   bool IsVarArg                         = CLI.IsVarArg;
3149 
3150   MachineFunction &MF = DAG.getMachineFunction();
3151   MachineFrameInfo &MFI = MF.getFrameInfo();
3152   const TargetFrameLowering *TFL = Subtarget.getFrameLowering();
3153   MipsFunctionInfo *FuncInfo = MF.getInfo<MipsFunctionInfo>();
3154   bool IsPIC = isPositionIndependent();
3155 
3156   // Analyze operands of the call, assigning locations to each operand.
3157   SmallVector<CCValAssign, 16> ArgLocs;
3158   MipsCCState CCInfo(
3159       CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs, *DAG.getContext(),
3160       MipsCCState::getSpecialCallingConvForCallee(Callee.getNode(), Subtarget));
3161 
3162   const ExternalSymbolSDNode *ES =
3163       dyn_cast_or_null<const ExternalSymbolSDNode>(Callee.getNode());
3164 
3165   // There is one case where CALLSEQ_START..CALLSEQ_END can be nested, which
3166   // is during the lowering of a call with a byval argument which produces
3167   // a call to memcpy. For the O32 case, this causes the caller to allocate
3168   // stack space for the reserved argument area for the callee, then recursively
3169   // again for the memcpy call. In the NEWABI case, this doesn't occur as those
3170   // ABIs mandate that the callee allocates the reserved argument area. We do
3171   // still produce nested CALLSEQ_START..CALLSEQ_END with zero space though.
3172   //
3173   // If the callee has a byval argument and memcpy is used, we are mandated
3174   // to already have produced a reserved argument area for the callee for O32.
3175   // Therefore, the reserved argument area can be reused for both calls.
3176   //
3177   // Other cases of calling memcpy cannot have a chain with a CALLSEQ_START
3178   // present, as we have yet to hook that node onto the chain.
3179   //
3180   // Hence, the CALLSEQ_START and CALLSEQ_END nodes can be eliminated in this
3181   // case. GCC does a similar trick, in that wherever possible, it calculates
3182   // the maximum out going argument area (including the reserved area), and
3183   // preallocates the stack space on entrance to the caller.
3184   //
3185   // FIXME: We should do the same for efficiency and space.
3186 
3187   // Note: The check on the calling convention below must match
3188   //       MipsABIInfo::GetCalleeAllocdArgSizeInBytes().
3189   bool MemcpyInByVal = ES &&
3190                        StringRef(ES->getSymbol()) == StringRef("memcpy") &&
3191                        CallConv != CallingConv::Fast &&
3192                        Chain.getOpcode() == ISD::CALLSEQ_START;
3193 
3194   // Allocate the reserved argument area. It seems strange to do this from the
3195   // caller side but removing it breaks the frame size calculation.
3196   unsigned ReservedArgArea =
3197       MemcpyInByVal ? 0 : ABI.GetCalleeAllocdArgSizeInBytes(CallConv);
3198   CCInfo.AllocateStack(ReservedArgArea, Align(1));
3199 
3200   CCInfo.AnalyzeCallOperands(Outs, CC_Mips, CLI.getArgs(),
3201                              ES ? ES->getSymbol() : nullptr);
3202 
3203   // Get a count of how many bytes are to be pushed on the stack.
3204   unsigned NextStackOffset = CCInfo.getNextStackOffset();
3205 
3206   // Call site info for function parameters tracking.
3207   MachineFunction::CallSiteInfo CSInfo;
3208 
3209   // Check if it's really possible to do a tail call. Restrict it to functions
3210   // that are part of this compilation unit.
3211   bool InternalLinkage = false;
3212   if (IsTailCall) {
3213     IsTailCall = isEligibleForTailCallOptimization(
3214         CCInfo, NextStackOffset, *MF.getInfo<MipsFunctionInfo>());
3215      if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
3216       InternalLinkage = G->getGlobal()->hasInternalLinkage();
3217       IsTailCall &= (InternalLinkage || G->getGlobal()->hasLocalLinkage() ||
3218                      G->getGlobal()->hasPrivateLinkage() ||
3219                      G->getGlobal()->hasHiddenVisibility() ||
3220                      G->getGlobal()->hasProtectedVisibility());
3221      }
3222   }
3223   if (!IsTailCall && CLI.CB && CLI.CB->isMustTailCall())
3224     report_fatal_error("failed to perform tail call elimination on a call "
3225                        "site marked musttail");
3226 
3227   if (IsTailCall)
3228     ++NumTailCalls;
3229 
3230   // Chain is the output chain of the last Load/Store or CopyToReg node.
3231   // ByValChain is the output chain of the last Memcpy node created for copying
3232   // byval arguments to the stack.
3233   unsigned StackAlignment = TFL->getStackAlignment();
3234   NextStackOffset = alignTo(NextStackOffset, StackAlignment);
3235   SDValue NextStackOffsetVal = DAG.getIntPtrConstant(NextStackOffset, DL, true);
3236 
3237   if (!(IsTailCall || MemcpyInByVal))
3238     Chain = DAG.getCALLSEQ_START(Chain, NextStackOffset, 0, DL);
3239 
3240   SDValue StackPtr =
3241       DAG.getCopyFromReg(Chain, DL, ABI.IsN64() ? Mips::SP_64 : Mips::SP,
3242                          getPointerTy(DAG.getDataLayout()));
3243 
3244   std::deque<std::pair<unsigned, SDValue>> RegsToPass;
3245   SmallVector<SDValue, 8> MemOpChains;
3246 
3247   CCInfo.rewindByValRegsInfo();
3248 
3249   // Walk the register/memloc assignments, inserting copies/loads.
3250   for (unsigned i = 0, e = ArgLocs.size(), OutIdx = 0; i != e; ++i, ++OutIdx) {
3251     SDValue Arg = OutVals[OutIdx];
3252     CCValAssign &VA = ArgLocs[i];
3253     MVT ValVT = VA.getValVT(), LocVT = VA.getLocVT();
3254     ISD::ArgFlagsTy Flags = Outs[OutIdx].Flags;
3255     bool UseUpperBits = false;
3256 
3257     // ByVal Arg.
3258     if (Flags.isByVal()) {
3259       unsigned FirstByValReg, LastByValReg;
3260       unsigned ByValIdx = CCInfo.getInRegsParamsProcessed();
3261       CCInfo.getInRegsParamInfo(ByValIdx, FirstByValReg, LastByValReg);
3262 
3263       assert(Flags.getByValSize() &&
3264              "ByVal args of size 0 should have been ignored by front-end.");
3265       assert(ByValIdx < CCInfo.getInRegsParamsCount());
3266       assert(!IsTailCall &&
3267              "Do not tail-call optimize if there is a byval argument.");
3268       passByValArg(Chain, DL, RegsToPass, MemOpChains, StackPtr, MFI, DAG, Arg,
3269                    FirstByValReg, LastByValReg, Flags, Subtarget.isLittle(),
3270                    VA);
3271       CCInfo.nextInRegsParam();
3272       continue;
3273     }
3274 
3275     // Promote the value if needed.
3276     switch (VA.getLocInfo()) {
3277     default:
3278       llvm_unreachable("Unknown loc info!");
3279     case CCValAssign::Full:
3280       if (VA.isRegLoc()) {
3281         if ((ValVT == MVT::f32 && LocVT == MVT::i32) ||
3282             (ValVT == MVT::f64 && LocVT == MVT::i64) ||
3283             (ValVT == MVT::i64 && LocVT == MVT::f64))
3284           Arg = DAG.getNode(ISD::BITCAST, DL, LocVT, Arg);
3285         else if (ValVT == MVT::f64 && LocVT == MVT::i32) {
3286           SDValue Lo = DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32,
3287                                    Arg, DAG.getConstant(0, DL, MVT::i32));
3288           SDValue Hi = DAG.getNode(MipsISD::ExtractElementF64, DL, MVT::i32,
3289                                    Arg, DAG.getConstant(1, DL, MVT::i32));
3290           if (!Subtarget.isLittle())
3291             std::swap(Lo, Hi);
3292 
3293           assert(VA.needsCustom());
3294 
3295           Register LocRegLo = VA.getLocReg();
3296           Register LocRegHigh = ArgLocs[++i].getLocReg();
3297           RegsToPass.push_back(std::make_pair(LocRegLo, Lo));
3298           RegsToPass.push_back(std::make_pair(LocRegHigh, Hi));
3299           continue;
3300         }
3301       }
3302       break;
3303     case CCValAssign::BCvt:
3304       Arg = DAG.getNode(ISD::BITCAST, DL, LocVT, Arg);
3305       break;
3306     case CCValAssign::SExtUpper:
3307       UseUpperBits = true;
3308       LLVM_FALLTHROUGH;
3309     case CCValAssign::SExt:
3310       Arg = DAG.getNode(ISD::SIGN_EXTEND, DL, LocVT, Arg);
3311       break;
3312     case CCValAssign::ZExtUpper:
3313       UseUpperBits = true;
3314       LLVM_FALLTHROUGH;
3315     case CCValAssign::ZExt:
3316       Arg = DAG.getNode(ISD::ZERO_EXTEND, DL, LocVT, Arg);
3317       break;
3318     case CCValAssign::AExtUpper:
3319       UseUpperBits = true;
3320       LLVM_FALLTHROUGH;
3321     case CCValAssign::AExt:
3322       Arg = DAG.getNode(ISD::ANY_EXTEND, DL, LocVT, Arg);
3323       break;
3324     }
3325 
3326     if (UseUpperBits) {
3327       unsigned ValSizeInBits = Outs[OutIdx].ArgVT.getSizeInBits();
3328       unsigned LocSizeInBits = VA.getLocVT().getSizeInBits();
3329       Arg = DAG.getNode(
3330           ISD::SHL, DL, VA.getLocVT(), Arg,
3331           DAG.getConstant(LocSizeInBits - ValSizeInBits, DL, VA.getLocVT()));
3332     }
3333 
3334     // Arguments that can be passed on register must be kept at
3335     // RegsToPass vector
3336     if (VA.isRegLoc()) {
3337       RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
3338 
3339       // If the parameter is passed through reg $D, which splits into
3340       // two physical registers, avoid creating call site info.
3341       if (Mips::AFGR64RegClass.contains(VA.getLocReg()))
3342         continue;
3343 
3344       // Collect CSInfo about which register passes which parameter.
3345       const TargetOptions &Options = DAG.getTarget().Options;
3346       if (Options.SupportsDebugEntryValues)
3347         CSInfo.emplace_back(VA.getLocReg(), i);
3348 
3349       continue;
3350     }
3351 
3352     // Register can't get to this point...
3353     assert(VA.isMemLoc());
3354 
3355     // emit ISD::STORE whichs stores the
3356     // parameter value to a stack Location
3357     MemOpChains.push_back(passArgOnStack(StackPtr, VA.getLocMemOffset(),
3358                                          Chain, Arg, DL, IsTailCall, DAG));
3359   }
3360 
3361   // Transform all store nodes into one single node because all store
3362   // nodes are independent of each other.
3363   if (!MemOpChains.empty())
3364     Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, MemOpChains);
3365 
3366   // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
3367   // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
3368   // node so that legalize doesn't hack it.
3369 
3370   EVT Ty = Callee.getValueType();
3371   bool GlobalOrExternal = false, IsCallReloc = false;
3372 
3373   // The long-calls feature is ignored in case of PIC.
3374   // While we do not support -mshared / -mno-shared properly,
3375   // ignore long-calls in case of -mabicalls too.
3376   if (!Subtarget.isABICalls() && !IsPIC) {
3377     // If the function should be called using "long call",
3378     // get its address into a register to prevent using
3379     // of the `jal` instruction for the direct call.
3380     if (auto *N = dyn_cast<ExternalSymbolSDNode>(Callee)) {
3381       if (Subtarget.useLongCalls())
3382         Callee = Subtarget.hasSym32()
3383                      ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
3384                      : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
3385     } else if (auto *N = dyn_cast<GlobalAddressSDNode>(Callee)) {
3386       bool UseLongCalls = Subtarget.useLongCalls();
3387       // If the function has long-call/far/near attribute
3388       // it overrides command line switch pased to the backend.
3389       if (auto *F = dyn_cast<Function>(N->getGlobal())) {
3390         if (F->hasFnAttribute("long-call"))
3391           UseLongCalls = true;
3392         else if (F->hasFnAttribute("short-call"))
3393           UseLongCalls = false;
3394       }
3395       if (UseLongCalls)
3396         Callee = Subtarget.hasSym32()
3397                      ? getAddrNonPIC(N, SDLoc(N), Ty, DAG)
3398                      : getAddrNonPICSym64(N, SDLoc(N), Ty, DAG);
3399     }
3400   }
3401 
3402   if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
3403     if (IsPIC) {
3404       const GlobalValue *Val = G->getGlobal();
3405       InternalLinkage = Val->hasInternalLinkage();
3406 
3407       if (InternalLinkage)
3408         Callee = getAddrLocal(G, DL, Ty, DAG, ABI.IsN32() || ABI.IsN64());
3409       else if (Subtarget.useXGOT()) {
3410         Callee = getAddrGlobalLargeGOT(G, DL, Ty, DAG, MipsII::MO_CALL_HI16,
3411                                        MipsII::MO_CALL_LO16, Chain,
3412                                        FuncInfo->callPtrInfo(MF, Val));
3413         IsCallReloc = true;
3414       } else {
3415         Callee = getAddrGlobal(G, DL, Ty, DAG, MipsII::MO_GOT_CALL, Chain,
3416                                FuncInfo->callPtrInfo(MF, Val));
3417         IsCallReloc = true;
3418       }
3419     } else
3420       Callee = DAG.getTargetGlobalAddress(G->getGlobal(), DL,
3421                                           getPointerTy(DAG.getDataLayout()), 0,
3422                                           MipsII::MO_NO_FLAG);
3423     GlobalOrExternal = true;
3424   }
3425   else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
3426     const char *Sym = S->getSymbol();
3427 
3428     if (!IsPIC) // static
3429       Callee = DAG.getTargetExternalSymbol(
3430           Sym, getPointerTy(DAG.getDataLayout()), MipsII::MO_NO_FLAG);
3431     else if (Subtarget.useXGOT()) {
3432       Callee = getAddrGlobalLargeGOT(S, DL, Ty, DAG, MipsII::MO_CALL_HI16,
3433                                      MipsII::MO_CALL_LO16, Chain,
3434                                      FuncInfo->callPtrInfo(MF, Sym));
3435       IsCallReloc = true;
3436     } else { // PIC
3437       Callee = getAddrGlobal(S, DL, Ty, DAG, MipsII::MO_GOT_CALL, Chain,
3438                              FuncInfo->callPtrInfo(MF, Sym));
3439       IsCallReloc = true;
3440     }
3441 
3442     GlobalOrExternal = true;
3443   }
3444 
3445   SmallVector<SDValue, 8> Ops(1, Chain);
3446   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
3447 
3448   getOpndList(Ops, RegsToPass, IsPIC, GlobalOrExternal, InternalLinkage,
3449               IsCallReloc, CLI, Callee, Chain);
3450 
3451   if (IsTailCall) {
3452     MF.getFrameInfo().setHasTailCall();
3453     SDValue Ret = DAG.getNode(MipsISD::TailCall, DL, MVT::Other, Ops);
3454     DAG.addCallSiteInfo(Ret.getNode(), std::move(CSInfo));
3455     return Ret;
3456   }
3457 
3458   Chain = DAG.getNode(MipsISD::JmpLink, DL, NodeTys, Ops);
3459   SDValue InFlag = Chain.getValue(1);
3460 
3461   DAG.addCallSiteInfo(Chain.getNode(), std::move(CSInfo));
3462 
3463   // Create the CALLSEQ_END node in the case of where it is not a call to
3464   // memcpy.
3465   if (!(MemcpyInByVal)) {
3466     Chain = DAG.getCALLSEQ_END(Chain, NextStackOffsetVal,
3467                                DAG.getIntPtrConstant(0, DL, true), InFlag, DL);
3468     InFlag = Chain.getValue(1);
3469   }
3470 
3471   // Handle result values, copying them out of physregs into vregs that we
3472   // return.
3473   return LowerCallResult(Chain, InFlag, CallConv, IsVarArg, Ins, DL, DAG,
3474                          InVals, CLI);
3475 }
3476 
3477 /// LowerCallResult - Lower the result values of a call into the
3478 /// appropriate copies out of appropriate physical registers.
3479 SDValue MipsTargetLowering::LowerCallResult(
3480     SDValue Chain, SDValue InFlag, CallingConv::ID CallConv, bool IsVarArg,
3481     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &DL,
3482     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals,
3483     TargetLowering::CallLoweringInfo &CLI) const {
3484   // Assign locations to each value returned by this call.
3485   SmallVector<CCValAssign, 16> RVLocs;
3486   MipsCCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), RVLocs,
3487                      *DAG.getContext());
3488 
3489   const ExternalSymbolSDNode *ES =
3490       dyn_cast_or_null<const ExternalSymbolSDNode>(CLI.Callee.getNode());
3491   CCInfo.AnalyzeCallResult(Ins, RetCC_Mips, CLI.RetTy,
3492                            ES ? ES->getSymbol() : nullptr);
3493 
3494   // Copy all of the result registers out of their specified physreg.
3495   for (unsigned i = 0; i != RVLocs.size(); ++i) {
3496     CCValAssign &VA = RVLocs[i];
3497     assert(VA.isRegLoc() && "Can only return in registers!");
3498 
3499     SDValue Val = DAG.getCopyFromReg(Chain, DL, RVLocs[i].getLocReg(),
3500                                      RVLocs[i].getLocVT(), InFlag);
3501     Chain = Val.getValue(1);
3502     InFlag = Val.getValue(2);
3503 
3504     if (VA.isUpperBitsInLoc()) {
3505       unsigned ValSizeInBits = Ins[i].ArgVT.getSizeInBits();
3506       unsigned LocSizeInBits = VA.getLocVT().getSizeInBits();
3507       unsigned Shift =
3508           VA.getLocInfo() == CCValAssign::ZExtUpper ? ISD::SRL : ISD::SRA;
3509       Val = DAG.getNode(
3510           Shift, DL, VA.getLocVT(), Val,
3511           DAG.getConstant(LocSizeInBits - ValSizeInBits, DL, VA.getLocVT()));
3512     }
3513 
3514     switch (VA.getLocInfo()) {
3515     default:
3516       llvm_unreachable("Unknown loc info!");
3517     case CCValAssign::Full:
3518       break;
3519     case CCValAssign::BCvt:
3520       Val = DAG.getNode(ISD::BITCAST, DL, VA.getValVT(), Val);
3521       break;
3522     case CCValAssign::AExt:
3523     case CCValAssign::AExtUpper:
3524       Val = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), Val);
3525       break;
3526     case CCValAssign::ZExt:
3527     case CCValAssign::ZExtUpper:
3528       Val = DAG.getNode(ISD::AssertZext, DL, VA.getLocVT(), Val,
3529                         DAG.getValueType(VA.getValVT()));
3530       Val = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), Val);
3531       break;
3532     case CCValAssign::SExt:
3533     case CCValAssign::SExtUpper:
3534       Val = DAG.getNode(ISD::AssertSext, DL, VA.getLocVT(), Val,
3535                         DAG.getValueType(VA.getValVT()));
3536       Val = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), Val);
3537       break;
3538     }
3539 
3540     InVals.push_back(Val);
3541   }
3542 
3543   return Chain;
3544 }
3545 
3546 static SDValue UnpackFromArgumentSlot(SDValue Val, const CCValAssign &VA,
3547                                       EVT ArgVT, const SDLoc &DL,
3548                                       SelectionDAG &DAG) {
3549   MVT LocVT = VA.getLocVT();
3550   EVT ValVT = VA.getValVT();
3551 
3552   // Shift into the upper bits if necessary.
3553   switch (VA.getLocInfo()) {
3554   default:
3555     break;
3556   case CCValAssign::AExtUpper:
3557   case CCValAssign::SExtUpper:
3558   case CCValAssign::ZExtUpper: {
3559     unsigned ValSizeInBits = ArgVT.getSizeInBits();
3560     unsigned LocSizeInBits = VA.getLocVT().getSizeInBits();
3561     unsigned Opcode =
3562         VA.getLocInfo() == CCValAssign::ZExtUpper ? ISD::SRL : ISD::SRA;
3563     Val = DAG.getNode(
3564         Opcode, DL, VA.getLocVT(), Val,
3565         DAG.getConstant(LocSizeInBits - ValSizeInBits, DL, VA.getLocVT()));
3566     break;
3567   }
3568   }
3569 
3570   // If this is an value smaller than the argument slot size (32-bit for O32,
3571   // 64-bit for N32/N64), it has been promoted in some way to the argument slot
3572   // size. Extract the value and insert any appropriate assertions regarding
3573   // sign/zero extension.
3574   switch (VA.getLocInfo()) {
3575   default:
3576     llvm_unreachable("Unknown loc info!");
3577   case CCValAssign::Full:
3578     break;
3579   case CCValAssign::AExtUpper:
3580   case CCValAssign::AExt:
3581     Val = DAG.getNode(ISD::TRUNCATE, DL, ValVT, Val);
3582     break;
3583   case CCValAssign::SExtUpper:
3584   case CCValAssign::SExt:
3585     Val = DAG.getNode(ISD::AssertSext, DL, LocVT, Val, DAG.getValueType(ValVT));
3586     Val = DAG.getNode(ISD::TRUNCATE, DL, ValVT, Val);
3587     break;
3588   case CCValAssign::ZExtUpper:
3589   case CCValAssign::ZExt:
3590     Val = DAG.getNode(ISD::AssertZext, DL, LocVT, Val, DAG.getValueType(ValVT));
3591     Val = DAG.getNode(ISD::TRUNCATE, DL, ValVT, Val);
3592     break;
3593   case CCValAssign::BCvt:
3594     Val = DAG.getNode(ISD::BITCAST, DL, ValVT, Val);
3595     break;
3596   }
3597 
3598   return Val;
3599 }
3600 
3601 //===----------------------------------------------------------------------===//
3602 //             Formal Arguments Calling Convention Implementation
3603 //===----------------------------------------------------------------------===//
3604 /// LowerFormalArguments - transform physical registers into virtual registers
3605 /// and generate load operations for arguments places on the stack.
3606 SDValue MipsTargetLowering::LowerFormalArguments(
3607     SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
3608     const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &DL,
3609     SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const {
3610   MachineFunction &MF = DAG.getMachineFunction();
3611   MachineFrameInfo &MFI = MF.getFrameInfo();
3612   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
3613 
3614   MipsFI->setVarArgsFrameIndex(0);
3615 
3616   // Used with vargs to acumulate store chains.
3617   std::vector<SDValue> OutChains;
3618 
3619   // Assign locations to all of the incoming arguments.
3620   SmallVector<CCValAssign, 16> ArgLocs;
3621   MipsCCState CCInfo(CallConv, IsVarArg, DAG.getMachineFunction(), ArgLocs,
3622                      *DAG.getContext());
3623   CCInfo.AllocateStack(ABI.GetCalleeAllocdArgSizeInBytes(CallConv), Align(1));
3624   const Function &Func = DAG.getMachineFunction().getFunction();
3625   Function::const_arg_iterator FuncArg = Func.arg_begin();
3626 
3627   if (Func.hasFnAttribute("interrupt") && !Func.arg_empty())
3628     report_fatal_error(
3629         "Functions with the interrupt attribute cannot have arguments!");
3630 
3631   CCInfo.AnalyzeFormalArguments(Ins, CC_Mips_FixedArg);
3632   MipsFI->setFormalArgInfo(CCInfo.getNextStackOffset(),
3633                            CCInfo.getInRegsParamsCount() > 0);
3634 
3635   unsigned CurArgIdx = 0;
3636   CCInfo.rewindByValRegsInfo();
3637 
3638   for (unsigned i = 0, e = ArgLocs.size(), InsIdx = 0; i != e; ++i, ++InsIdx) {
3639     CCValAssign &VA = ArgLocs[i];
3640     if (Ins[InsIdx].isOrigArg()) {
3641       std::advance(FuncArg, Ins[InsIdx].getOrigArgIndex() - CurArgIdx);
3642       CurArgIdx = Ins[InsIdx].getOrigArgIndex();
3643     }
3644     EVT ValVT = VA.getValVT();
3645     ISD::ArgFlagsTy Flags = Ins[InsIdx].Flags;
3646     bool IsRegLoc = VA.isRegLoc();
3647 
3648     if (Flags.isByVal()) {
3649       assert(Ins[InsIdx].isOrigArg() && "Byval arguments cannot be implicit");
3650       unsigned FirstByValReg, LastByValReg;
3651       unsigned ByValIdx = CCInfo.getInRegsParamsProcessed();
3652       CCInfo.getInRegsParamInfo(ByValIdx, FirstByValReg, LastByValReg);
3653 
3654       assert(Flags.getByValSize() &&
3655              "ByVal args of size 0 should have been ignored by front-end.");
3656       assert(ByValIdx < CCInfo.getInRegsParamsCount());
3657       copyByValRegs(Chain, DL, OutChains, DAG, Flags, InVals, &*FuncArg,
3658                     FirstByValReg, LastByValReg, VA, CCInfo);
3659       CCInfo.nextInRegsParam();
3660       continue;
3661     }
3662 
3663     // Arguments stored on registers
3664     if (IsRegLoc) {
3665       MVT RegVT = VA.getLocVT();
3666       Register ArgReg = VA.getLocReg();
3667       const TargetRegisterClass *RC = getRegClassFor(RegVT);
3668 
3669       // Transform the arguments stored on
3670       // physical registers into virtual ones
3671       unsigned Reg = addLiveIn(DAG.getMachineFunction(), ArgReg, RC);
3672       SDValue ArgValue = DAG.getCopyFromReg(Chain, DL, Reg, RegVT);
3673 
3674       ArgValue =
3675           UnpackFromArgumentSlot(ArgValue, VA, Ins[InsIdx].ArgVT, DL, DAG);
3676 
3677       // Handle floating point arguments passed in integer registers and
3678       // long double arguments passed in floating point registers.
3679       if ((RegVT == MVT::i32 && ValVT == MVT::f32) ||
3680           (RegVT == MVT::i64 && ValVT == MVT::f64) ||
3681           (RegVT == MVT::f64 && ValVT == MVT::i64))
3682         ArgValue = DAG.getNode(ISD::BITCAST, DL, ValVT, ArgValue);
3683       else if (ABI.IsO32() && RegVT == MVT::i32 &&
3684                ValVT == MVT::f64) {
3685         assert(VA.needsCustom() && "Expected custom argument for f64 split");
3686         CCValAssign &NextVA = ArgLocs[++i];
3687         unsigned Reg2 =
3688             addLiveIn(DAG.getMachineFunction(), NextVA.getLocReg(), RC);
3689         SDValue ArgValue2 = DAG.getCopyFromReg(Chain, DL, Reg2, RegVT);
3690         if (!Subtarget.isLittle())
3691           std::swap(ArgValue, ArgValue2);
3692         ArgValue = DAG.getNode(MipsISD::BuildPairF64, DL, MVT::f64,
3693                                ArgValue, ArgValue2);
3694       }
3695 
3696       InVals.push_back(ArgValue);
3697     } else { // VA.isRegLoc()
3698       MVT LocVT = VA.getLocVT();
3699 
3700       assert(!VA.needsCustom() && "unexpected custom memory argument");
3701 
3702       if (ABI.IsO32()) {
3703         // We ought to be able to use LocVT directly but O32 sets it to i32
3704         // when allocating floating point values to integer registers.
3705         // This shouldn't influence how we load the value into registers unless
3706         // we are targeting softfloat.
3707         if (VA.getValVT().isFloatingPoint() && !Subtarget.useSoftFloat())
3708           LocVT = VA.getValVT();
3709       }
3710 
3711       // Only arguments pased on the stack should make it here.
3712       assert(VA.isMemLoc());
3713 
3714       // The stack pointer offset is relative to the caller stack frame.
3715       int FI = MFI.CreateFixedObject(LocVT.getSizeInBits() / 8,
3716                                      VA.getLocMemOffset(), true);
3717 
3718       // Create load nodes to retrieve arguments from the stack
3719       SDValue FIN = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
3720       SDValue ArgValue = DAG.getLoad(
3721           LocVT, DL, Chain, FIN,
3722           MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), FI));
3723       OutChains.push_back(ArgValue.getValue(1));
3724 
3725       ArgValue =
3726           UnpackFromArgumentSlot(ArgValue, VA, Ins[InsIdx].ArgVT, DL, DAG);
3727 
3728       InVals.push_back(ArgValue);
3729     }
3730   }
3731 
3732   for (unsigned i = 0, e = ArgLocs.size(), InsIdx = 0; i != e; ++i, ++InsIdx) {
3733 
3734     if (ArgLocs[i].needsCustom()) {
3735       ++i;
3736       continue;
3737     }
3738 
3739     // The mips ABIs for returning structs by value requires that we copy
3740     // the sret argument into $v0 for the return. Save the argument into
3741     // a virtual register so that we can access it from the return points.
3742     if (Ins[InsIdx].Flags.isSRet()) {
3743       unsigned Reg = MipsFI->getSRetReturnReg();
3744       if (!Reg) {
3745         Reg = MF.getRegInfo().createVirtualRegister(
3746             getRegClassFor(ABI.IsN64() ? MVT::i64 : MVT::i32));
3747         MipsFI->setSRetReturnReg(Reg);
3748       }
3749       SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), DL, Reg, InVals[i]);
3750       Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Copy, Chain);
3751       break;
3752     }
3753   }
3754 
3755   if (IsVarArg)
3756     writeVarArgRegs(OutChains, Chain, DL, DAG, CCInfo);
3757 
3758   // All stores are grouped in one node to allow the matching between
3759   // the size of Ins and InVals. This only happens when on varg functions
3760   if (!OutChains.empty()) {
3761     OutChains.push_back(Chain);
3762     Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, OutChains);
3763   }
3764 
3765   return Chain;
3766 }
3767 
3768 //===----------------------------------------------------------------------===//
3769 //               Return Value Calling Convention Implementation
3770 //===----------------------------------------------------------------------===//
3771 
3772 bool
3773 MipsTargetLowering::CanLowerReturn(CallingConv::ID CallConv,
3774                                    MachineFunction &MF, bool IsVarArg,
3775                                    const SmallVectorImpl<ISD::OutputArg> &Outs,
3776                                    LLVMContext &Context) const {
3777   SmallVector<CCValAssign, 16> RVLocs;
3778   MipsCCState CCInfo(CallConv, IsVarArg, MF, RVLocs, Context);
3779   return CCInfo.CheckReturn(Outs, RetCC_Mips);
3780 }
3781 
3782 bool MipsTargetLowering::shouldSignExtendTypeInLibCall(EVT Type,
3783                                                        bool IsSigned) const {
3784   if ((ABI.IsN32() || ABI.IsN64()) && Type == MVT::i32)
3785       return true;
3786 
3787   return IsSigned;
3788 }
3789 
3790 SDValue
3791 MipsTargetLowering::LowerInterruptReturn(SmallVectorImpl<SDValue> &RetOps,
3792                                          const SDLoc &DL,
3793                                          SelectionDAG &DAG) const {
3794   MachineFunction &MF = DAG.getMachineFunction();
3795   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
3796 
3797   MipsFI->setISR();
3798 
3799   return DAG.getNode(MipsISD::ERet, DL, MVT::Other, RetOps);
3800 }
3801 
3802 SDValue
3803 MipsTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
3804                                 bool IsVarArg,
3805                                 const SmallVectorImpl<ISD::OutputArg> &Outs,
3806                                 const SmallVectorImpl<SDValue> &OutVals,
3807                                 const SDLoc &DL, SelectionDAG &DAG) const {
3808   // CCValAssign - represent the assignment of
3809   // the return value to a location
3810   SmallVector<CCValAssign, 16> RVLocs;
3811   MachineFunction &MF = DAG.getMachineFunction();
3812 
3813   // CCState - Info about the registers and stack slot.
3814   MipsCCState CCInfo(CallConv, IsVarArg, MF, RVLocs, *DAG.getContext());
3815 
3816   // Analyze return values.
3817   CCInfo.AnalyzeReturn(Outs, RetCC_Mips);
3818 
3819   SDValue Flag;
3820   SmallVector<SDValue, 4> RetOps(1, Chain);
3821 
3822   // Copy the result values into the output registers.
3823   for (unsigned i = 0; i != RVLocs.size(); ++i) {
3824     SDValue Val = OutVals[i];
3825     CCValAssign &VA = RVLocs[i];
3826     assert(VA.isRegLoc() && "Can only return in registers!");
3827     bool UseUpperBits = false;
3828 
3829     switch (VA.getLocInfo()) {
3830     default:
3831       llvm_unreachable("Unknown loc info!");
3832     case CCValAssign::Full:
3833       break;
3834     case CCValAssign::BCvt:
3835       Val = DAG.getNode(ISD::BITCAST, DL, VA.getLocVT(), Val);
3836       break;
3837     case CCValAssign::AExtUpper:
3838       UseUpperBits = true;
3839       LLVM_FALLTHROUGH;
3840     case CCValAssign::AExt:
3841       Val = DAG.getNode(ISD::ANY_EXTEND, DL, VA.getLocVT(), Val);
3842       break;
3843     case CCValAssign::ZExtUpper:
3844       UseUpperBits = true;
3845       LLVM_FALLTHROUGH;
3846     case CCValAssign::ZExt:
3847       Val = DAG.getNode(ISD::ZERO_EXTEND, DL, VA.getLocVT(), Val);
3848       break;
3849     case CCValAssign::SExtUpper:
3850       UseUpperBits = true;
3851       LLVM_FALLTHROUGH;
3852     case CCValAssign::SExt:
3853       Val = DAG.getNode(ISD::SIGN_EXTEND, DL, VA.getLocVT(), Val);
3854       break;
3855     }
3856 
3857     if (UseUpperBits) {
3858       unsigned ValSizeInBits = Outs[i].ArgVT.getSizeInBits();
3859       unsigned LocSizeInBits = VA.getLocVT().getSizeInBits();
3860       Val = DAG.getNode(
3861           ISD::SHL, DL, VA.getLocVT(), Val,
3862           DAG.getConstant(LocSizeInBits - ValSizeInBits, DL, VA.getLocVT()));
3863     }
3864 
3865     Chain = DAG.getCopyToReg(Chain, DL, VA.getLocReg(), Val, Flag);
3866 
3867     // Guarantee that all emitted copies are stuck together with flags.
3868     Flag = Chain.getValue(1);
3869     RetOps.push_back(DAG.getRegister(VA.getLocReg(), VA.getLocVT()));
3870   }
3871 
3872   // The mips ABIs for returning structs by value requires that we copy
3873   // the sret argument into $v0 for the return. We saved the argument into
3874   // a virtual register in the entry block, so now we copy the value out
3875   // and into $v0.
3876   if (MF.getFunction().hasStructRetAttr()) {
3877     MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
3878     unsigned Reg = MipsFI->getSRetReturnReg();
3879 
3880     if (!Reg)
3881       llvm_unreachable("sret virtual register not created in the entry block");
3882     SDValue Val =
3883         DAG.getCopyFromReg(Chain, DL, Reg, getPointerTy(DAG.getDataLayout()));
3884     unsigned V0 = ABI.IsN64() ? Mips::V0_64 : Mips::V0;
3885 
3886     Chain = DAG.getCopyToReg(Chain, DL, V0, Val, Flag);
3887     Flag = Chain.getValue(1);
3888     RetOps.push_back(DAG.getRegister(V0, getPointerTy(DAG.getDataLayout())));
3889   }
3890 
3891   RetOps[0] = Chain;  // Update chain.
3892 
3893   // Add the flag if we have it.
3894   if (Flag.getNode())
3895     RetOps.push_back(Flag);
3896 
3897   // ISRs must use "eret".
3898   if (DAG.getMachineFunction().getFunction().hasFnAttribute("interrupt"))
3899     return LowerInterruptReturn(RetOps, DL, DAG);
3900 
3901   // Standard return on Mips is a "jr $ra"
3902   return DAG.getNode(MipsISD::Ret, DL, MVT::Other, RetOps);
3903 }
3904 
3905 //===----------------------------------------------------------------------===//
3906 //                           Mips Inline Assembly Support
3907 //===----------------------------------------------------------------------===//
3908 
3909 /// getConstraintType - Given a constraint letter, return the type of
3910 /// constraint it is for this target.
3911 MipsTargetLowering::ConstraintType
3912 MipsTargetLowering::getConstraintType(StringRef Constraint) const {
3913   // Mips specific constraints
3914   // GCC config/mips/constraints.md
3915   //
3916   // 'd' : An address register. Equivalent to r
3917   //       unless generating MIPS16 code.
3918   // 'y' : Equivalent to r; retained for
3919   //       backwards compatibility.
3920   // 'c' : A register suitable for use in an indirect
3921   //       jump. This will always be $25 for -mabicalls.
3922   // 'l' : The lo register. 1 word storage.
3923   // 'x' : The hilo register pair. Double word storage.
3924   if (Constraint.size() == 1) {
3925     switch (Constraint[0]) {
3926       default : break;
3927       case 'd':
3928       case 'y':
3929       case 'f':
3930       case 'c':
3931       case 'l':
3932       case 'x':
3933         return C_RegisterClass;
3934       case 'R':
3935         return C_Memory;
3936     }
3937   }
3938 
3939   if (Constraint == "ZC")
3940     return C_Memory;
3941 
3942   return TargetLowering::getConstraintType(Constraint);
3943 }
3944 
3945 /// Examine constraint type and operand type and determine a weight value.
3946 /// This object must already have been set up with the operand type
3947 /// and the current alternative constraint selected.
3948 TargetLowering::ConstraintWeight
3949 MipsTargetLowering::getSingleConstraintMatchWeight(
3950     AsmOperandInfo &info, const char *constraint) const {
3951   ConstraintWeight weight = CW_Invalid;
3952   Value *CallOperandVal = info.CallOperandVal;
3953     // If we don't have a value, we can't do a match,
3954     // but allow it at the lowest weight.
3955   if (!CallOperandVal)
3956     return CW_Default;
3957   Type *type = CallOperandVal->getType();
3958   // Look at the constraint type.
3959   switch (*constraint) {
3960   default:
3961     weight = TargetLowering::getSingleConstraintMatchWeight(info, constraint);
3962     break;
3963   case 'd':
3964   case 'y':
3965     if (type->isIntegerTy())
3966       weight = CW_Register;
3967     break;
3968   case 'f': // FPU or MSA register
3969     if (Subtarget.hasMSA() && type->isVectorTy() &&
3970         type->getPrimitiveSizeInBits().getFixedSize() == 128)
3971       weight = CW_Register;
3972     else if (type->isFloatTy())
3973       weight = CW_Register;
3974     break;
3975   case 'c': // $25 for indirect jumps
3976   case 'l': // lo register
3977   case 'x': // hilo register pair
3978     if (type->isIntegerTy())
3979       weight = CW_SpecificReg;
3980     break;
3981   case 'I': // signed 16 bit immediate
3982   case 'J': // integer zero
3983   case 'K': // unsigned 16 bit immediate
3984   case 'L': // signed 32 bit immediate where lower 16 bits are 0
3985   case 'N': // immediate in the range of -65535 to -1 (inclusive)
3986   case 'O': // signed 15 bit immediate (+- 16383)
3987   case 'P': // immediate in the range of 65535 to 1 (inclusive)
3988     if (isa<ConstantInt>(CallOperandVal))
3989       weight = CW_Constant;
3990     break;
3991   case 'R':
3992     weight = CW_Memory;
3993     break;
3994   }
3995   return weight;
3996 }
3997 
3998 /// This is a helper function to parse a physical register string and split it
3999 /// into non-numeric and numeric parts (Prefix and Reg). The first boolean flag
4000 /// that is returned indicates whether parsing was successful. The second flag
4001 /// is true if the numeric part exists.
4002 static std::pair<bool, bool> parsePhysicalReg(StringRef C, StringRef &Prefix,
4003                                               unsigned long long &Reg) {
4004   if (C.front() != '{' || C.back() != '}')
4005     return std::make_pair(false, false);
4006 
4007   // Search for the first numeric character.
4008   StringRef::const_iterator I, B = C.begin() + 1, E = C.end() - 1;
4009   I = std::find_if(B, E, isdigit);
4010 
4011   Prefix = StringRef(B, I - B);
4012 
4013   // The second flag is set to false if no numeric characters were found.
4014   if (I == E)
4015     return std::make_pair(true, false);
4016 
4017   // Parse the numeric characters.
4018   return std::make_pair(!getAsUnsignedInteger(StringRef(I, E - I), 10, Reg),
4019                         true);
4020 }
4021 
4022 EVT MipsTargetLowering::getTypeForExtReturn(LLVMContext &Context, EVT VT,
4023                                             ISD::NodeType) const {
4024   bool Cond = !Subtarget.isABI_O32() && VT.getSizeInBits() == 32;
4025   EVT MinVT = getRegisterType(Context, Cond ? MVT::i64 : MVT::i32);
4026   return VT.bitsLT(MinVT) ? MinVT : VT;
4027 }
4028 
4029 std::pair<unsigned, const TargetRegisterClass *> MipsTargetLowering::
4030 parseRegForInlineAsmConstraint(StringRef C, MVT VT) const {
4031   const TargetRegisterInfo *TRI =
4032       Subtarget.getRegisterInfo();
4033   const TargetRegisterClass *RC;
4034   StringRef Prefix;
4035   unsigned long long Reg;
4036 
4037   std::pair<bool, bool> R = parsePhysicalReg(C, Prefix, Reg);
4038 
4039   if (!R.first)
4040     return std::make_pair(0U, nullptr);
4041 
4042   if ((Prefix == "hi" || Prefix == "lo")) { // Parse hi/lo.
4043     // No numeric characters follow "hi" or "lo".
4044     if (R.second)
4045       return std::make_pair(0U, nullptr);
4046 
4047     RC = TRI->getRegClass(Prefix == "hi" ?
4048                           Mips::HI32RegClassID : Mips::LO32RegClassID);
4049     return std::make_pair(*(RC->begin()), RC);
4050   } else if (Prefix.startswith("$msa")) {
4051     // Parse $msa(ir|csr|access|save|modify|request|map|unmap)
4052 
4053     // No numeric characters follow the name.
4054     if (R.second)
4055       return std::make_pair(0U, nullptr);
4056 
4057     Reg = StringSwitch<unsigned long long>(Prefix)
4058               .Case("$msair", Mips::MSAIR)
4059               .Case("$msacsr", Mips::MSACSR)
4060               .Case("$msaaccess", Mips::MSAAccess)
4061               .Case("$msasave", Mips::MSASave)
4062               .Case("$msamodify", Mips::MSAModify)
4063               .Case("$msarequest", Mips::MSARequest)
4064               .Case("$msamap", Mips::MSAMap)
4065               .Case("$msaunmap", Mips::MSAUnmap)
4066               .Default(0);
4067 
4068     if (!Reg)
4069       return std::make_pair(0U, nullptr);
4070 
4071     RC = TRI->getRegClass(Mips::MSACtrlRegClassID);
4072     return std::make_pair(Reg, RC);
4073   }
4074 
4075   if (!R.second)
4076     return std::make_pair(0U, nullptr);
4077 
4078   if (Prefix == "$f") { // Parse $f0-$f31.
4079     // If the size of FP registers is 64-bit or Reg is an even number, select
4080     // the 64-bit register class. Otherwise, select the 32-bit register class.
4081     if (VT == MVT::Other)
4082       VT = (Subtarget.isFP64bit() || !(Reg % 2)) ? MVT::f64 : MVT::f32;
4083 
4084     RC = getRegClassFor(VT);
4085 
4086     if (RC == &Mips::AFGR64RegClass) {
4087       assert(Reg % 2 == 0);
4088       Reg >>= 1;
4089     }
4090   } else if (Prefix == "$fcc") // Parse $fcc0-$fcc7.
4091     RC = TRI->getRegClass(Mips::FCCRegClassID);
4092   else if (Prefix == "$w") { // Parse $w0-$w31.
4093     RC = getRegClassFor((VT == MVT::Other) ? MVT::v16i8 : VT);
4094   } else { // Parse $0-$31.
4095     assert(Prefix == "$");
4096     RC = getRegClassFor((VT == MVT::Other) ? MVT::i32 : VT);
4097   }
4098 
4099   assert(Reg < RC->getNumRegs());
4100   return std::make_pair(*(RC->begin() + Reg), RC);
4101 }
4102 
4103 /// Given a register class constraint, like 'r', if this corresponds directly
4104 /// to an LLVM register class, return a register of 0 and the register class
4105 /// pointer.
4106 std::pair<unsigned, const TargetRegisterClass *>
4107 MipsTargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
4108                                                  StringRef Constraint,
4109                                                  MVT VT) const {
4110   if (Constraint.size() == 1) {
4111     switch (Constraint[0]) {
4112     case 'd': // Address register. Same as 'r' unless generating MIPS16 code.
4113     case 'y': // Same as 'r'. Exists for compatibility.
4114     case 'r':
4115       if (VT == MVT::i32 || VT == MVT::i16 || VT == MVT::i8 || VT == MVT::i1) {
4116         if (Subtarget.inMips16Mode())
4117           return std::make_pair(0U, &Mips::CPU16RegsRegClass);
4118         return std::make_pair(0U, &Mips::GPR32RegClass);
4119       }
4120       if (VT == MVT::i64 && !Subtarget.isGP64bit())
4121         return std::make_pair(0U, &Mips::GPR32RegClass);
4122       if (VT == MVT::i64 && Subtarget.isGP64bit())
4123         return std::make_pair(0U, &Mips::GPR64RegClass);
4124       // This will generate an error message
4125       return std::make_pair(0U, nullptr);
4126     case 'f': // FPU or MSA register
4127       if (VT == MVT::v16i8)
4128         return std::make_pair(0U, &Mips::MSA128BRegClass);
4129       else if (VT == MVT::v8i16 || VT == MVT::v8f16)
4130         return std::make_pair(0U, &Mips::MSA128HRegClass);
4131       else if (VT == MVT::v4i32 || VT == MVT::v4f32)
4132         return std::make_pair(0U, &Mips::MSA128WRegClass);
4133       else if (VT == MVT::v2i64 || VT == MVT::v2f64)
4134         return std::make_pair(0U, &Mips::MSA128DRegClass);
4135       else if (VT == MVT::f32)
4136         return std::make_pair(0U, &Mips::FGR32RegClass);
4137       else if ((VT == MVT::f64) && (!Subtarget.isSingleFloat())) {
4138         if (Subtarget.isFP64bit())
4139           return std::make_pair(0U, &Mips::FGR64RegClass);
4140         return std::make_pair(0U, &Mips::AFGR64RegClass);
4141       }
4142       break;
4143     case 'c': // register suitable for indirect jump
4144       if (VT == MVT::i32)
4145         return std::make_pair((unsigned)Mips::T9, &Mips::GPR32RegClass);
4146       if (VT == MVT::i64)
4147         return std::make_pair((unsigned)Mips::T9_64, &Mips::GPR64RegClass);
4148       // This will generate an error message
4149       return std::make_pair(0U, nullptr);
4150     case 'l': // use the `lo` register to store values
4151               // that are no bigger than a word
4152       if (VT == MVT::i32 || VT == MVT::i16 || VT == MVT::i8)
4153         return std::make_pair((unsigned)Mips::LO0, &Mips::LO32RegClass);
4154       return std::make_pair((unsigned)Mips::LO0_64, &Mips::LO64RegClass);
4155     case 'x': // use the concatenated `hi` and `lo` registers
4156               // to store doubleword values
4157       // Fixme: Not triggering the use of both hi and low
4158       // This will generate an error message
4159       return std::make_pair(0U, nullptr);
4160     }
4161   }
4162 
4163   if (!Constraint.empty()) {
4164     std::pair<unsigned, const TargetRegisterClass *> R;
4165     R = parseRegForInlineAsmConstraint(Constraint, VT);
4166 
4167     if (R.second)
4168       return R;
4169   }
4170 
4171   return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT);
4172 }
4173 
4174 /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
4175 /// vector.  If it is invalid, don't add anything to Ops.
4176 void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
4177                                                      std::string &Constraint,
4178                                                      std::vector<SDValue>&Ops,
4179                                                      SelectionDAG &DAG) const {
4180   SDLoc DL(Op);
4181   SDValue Result;
4182 
4183   // Only support length 1 constraints for now.
4184   if (Constraint.length() > 1) return;
4185 
4186   char ConstraintLetter = Constraint[0];
4187   switch (ConstraintLetter) {
4188   default: break; // This will fall through to the generic implementation
4189   case 'I': // Signed 16 bit constant
4190     // If this fails, the parent routine will give an error
4191     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4192       EVT Type = Op.getValueType();
4193       int64_t Val = C->getSExtValue();
4194       if (isInt<16>(Val)) {
4195         Result = DAG.getTargetConstant(Val, DL, Type);
4196         break;
4197       }
4198     }
4199     return;
4200   case 'J': // integer zero
4201     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4202       EVT Type = Op.getValueType();
4203       int64_t Val = C->getZExtValue();
4204       if (Val == 0) {
4205         Result = DAG.getTargetConstant(0, DL, Type);
4206         break;
4207       }
4208     }
4209     return;
4210   case 'K': // unsigned 16 bit immediate
4211     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4212       EVT Type = Op.getValueType();
4213       uint64_t Val = (uint64_t)C->getZExtValue();
4214       if (isUInt<16>(Val)) {
4215         Result = DAG.getTargetConstant(Val, DL, Type);
4216         break;
4217       }
4218     }
4219     return;
4220   case 'L': // signed 32 bit immediate where lower 16 bits are 0
4221     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4222       EVT Type = Op.getValueType();
4223       int64_t Val = C->getSExtValue();
4224       if ((isInt<32>(Val)) && ((Val & 0xffff) == 0)){
4225         Result = DAG.getTargetConstant(Val, DL, Type);
4226         break;
4227       }
4228     }
4229     return;
4230   case 'N': // immediate in the range of -65535 to -1 (inclusive)
4231     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4232       EVT Type = Op.getValueType();
4233       int64_t Val = C->getSExtValue();
4234       if ((Val >= -65535) && (Val <= -1)) {
4235         Result = DAG.getTargetConstant(Val, DL, Type);
4236         break;
4237       }
4238     }
4239     return;
4240   case 'O': // signed 15 bit immediate
4241     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4242       EVT Type = Op.getValueType();
4243       int64_t Val = C->getSExtValue();
4244       if ((isInt<15>(Val))) {
4245         Result = DAG.getTargetConstant(Val, DL, Type);
4246         break;
4247       }
4248     }
4249     return;
4250   case 'P': // immediate in the range of 1 to 65535 (inclusive)
4251     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
4252       EVT Type = Op.getValueType();
4253       int64_t Val = C->getSExtValue();
4254       if ((Val <= 65535) && (Val >= 1)) {
4255         Result = DAG.getTargetConstant(Val, DL, Type);
4256         break;
4257       }
4258     }
4259     return;
4260   }
4261 
4262   if (Result.getNode()) {
4263     Ops.push_back(Result);
4264     return;
4265   }
4266 
4267   TargetLowering::LowerAsmOperandForConstraint(Op, Constraint, Ops, DAG);
4268 }
4269 
4270 bool MipsTargetLowering::isLegalAddressingMode(const DataLayout &DL,
4271                                                const AddrMode &AM, Type *Ty,
4272                                                unsigned AS,
4273                                                Instruction *I) const {
4274   // No global is ever allowed as a base.
4275   if (AM.BaseGV)
4276     return false;
4277 
4278   switch (AM.Scale) {
4279   case 0: // "r+i" or just "i", depending on HasBaseReg.
4280     break;
4281   case 1:
4282     if (!AM.HasBaseReg) // allow "r+i".
4283       break;
4284     return false; // disallow "r+r" or "r+r+i".
4285   default:
4286     return false;
4287   }
4288 
4289   return true;
4290 }
4291 
4292 bool
4293 MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
4294   // The Mips target isn't yet aware of offsets.
4295   return false;
4296 }
4297 
4298 EVT MipsTargetLowering::getOptimalMemOpType(
4299     const MemOp &Op, const AttributeList &FuncAttributes) const {
4300   if (Subtarget.hasMips64())
4301     return MVT::i64;
4302 
4303   return MVT::i32;
4304 }
4305 
4306 bool MipsTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT,
4307                                       bool ForCodeSize) const {
4308   if (VT != MVT::f32 && VT != MVT::f64)
4309     return false;
4310   if (Imm.isNegZero())
4311     return false;
4312   return Imm.isZero();
4313 }
4314 
4315 unsigned MipsTargetLowering::getJumpTableEncoding() const {
4316 
4317   // FIXME: For space reasons this should be: EK_GPRel32BlockAddress.
4318   if (ABI.IsN64() && isPositionIndependent())
4319     return MachineJumpTableInfo::EK_GPRel64BlockAddress;
4320 
4321   return TargetLowering::getJumpTableEncoding();
4322 }
4323 
4324 bool MipsTargetLowering::useSoftFloat() const {
4325   return Subtarget.useSoftFloat();
4326 }
4327 
4328 void MipsTargetLowering::copyByValRegs(
4329     SDValue Chain, const SDLoc &DL, std::vector<SDValue> &OutChains,
4330     SelectionDAG &DAG, const ISD::ArgFlagsTy &Flags,
4331     SmallVectorImpl<SDValue> &InVals, const Argument *FuncArg,
4332     unsigned FirstReg, unsigned LastReg, const CCValAssign &VA,
4333     MipsCCState &State) const {
4334   MachineFunction &MF = DAG.getMachineFunction();
4335   MachineFrameInfo &MFI = MF.getFrameInfo();
4336   unsigned GPRSizeInBytes = Subtarget.getGPRSizeInBytes();
4337   unsigned NumRegs = LastReg - FirstReg;
4338   unsigned RegAreaSize = NumRegs * GPRSizeInBytes;
4339   unsigned FrameObjSize = std::max(Flags.getByValSize(), RegAreaSize);
4340   int FrameObjOffset;
4341   ArrayRef<MCPhysReg> ByValArgRegs = ABI.GetByValArgRegs();
4342 
4343   if (RegAreaSize)
4344     FrameObjOffset =
4345         (int)ABI.GetCalleeAllocdArgSizeInBytes(State.getCallingConv()) -
4346         (int)((ByValArgRegs.size() - FirstReg) * GPRSizeInBytes);
4347   else
4348     FrameObjOffset = VA.getLocMemOffset();
4349 
4350   // Create frame object.
4351   EVT PtrTy = getPointerTy(DAG.getDataLayout());
4352   // Make the fixed object stored to mutable so that the load instructions
4353   // referencing it have their memory dependencies added.
4354   // Set the frame object as isAliased which clears the underlying objects
4355   // vector in ScheduleDAGInstrs::buildSchedGraph() resulting in addition of all
4356   // stores as dependencies for loads referencing this fixed object.
4357   int FI = MFI.CreateFixedObject(FrameObjSize, FrameObjOffset, false, true);
4358   SDValue FIN = DAG.getFrameIndex(FI, PtrTy);
4359   InVals.push_back(FIN);
4360 
4361   if (!NumRegs)
4362     return;
4363 
4364   // Copy arg registers.
4365   MVT RegTy = MVT::getIntegerVT(GPRSizeInBytes * 8);
4366   const TargetRegisterClass *RC = getRegClassFor(RegTy);
4367 
4368   for (unsigned I = 0; I < NumRegs; ++I) {
4369     unsigned ArgReg = ByValArgRegs[FirstReg + I];
4370     unsigned VReg = addLiveIn(MF, ArgReg, RC);
4371     unsigned Offset = I * GPRSizeInBytes;
4372     SDValue StorePtr = DAG.getNode(ISD::ADD, DL, PtrTy, FIN,
4373                                    DAG.getConstant(Offset, DL, PtrTy));
4374     SDValue Store = DAG.getStore(Chain, DL, DAG.getRegister(VReg, RegTy),
4375                                  StorePtr, MachinePointerInfo(FuncArg, Offset));
4376     OutChains.push_back(Store);
4377   }
4378 }
4379 
4380 // Copy byVal arg to registers and stack.
4381 void MipsTargetLowering::passByValArg(
4382     SDValue Chain, const SDLoc &DL,
4383     std::deque<std::pair<unsigned, SDValue>> &RegsToPass,
4384     SmallVectorImpl<SDValue> &MemOpChains, SDValue StackPtr,
4385     MachineFrameInfo &MFI, SelectionDAG &DAG, SDValue Arg, unsigned FirstReg,
4386     unsigned LastReg, const ISD::ArgFlagsTy &Flags, bool isLittle,
4387     const CCValAssign &VA) const {
4388   unsigned ByValSizeInBytes = Flags.getByValSize();
4389   unsigned OffsetInBytes = 0; // From beginning of struct
4390   unsigned RegSizeInBytes = Subtarget.getGPRSizeInBytes();
4391   Align Alignment =
4392       std::min(Flags.getNonZeroByValAlign(), Align(RegSizeInBytes));
4393   EVT PtrTy = getPointerTy(DAG.getDataLayout()),
4394       RegTy = MVT::getIntegerVT(RegSizeInBytes * 8);
4395   unsigned NumRegs = LastReg - FirstReg;
4396 
4397   if (NumRegs) {
4398     ArrayRef<MCPhysReg> ArgRegs = ABI.GetByValArgRegs();
4399     bool LeftoverBytes = (NumRegs * RegSizeInBytes > ByValSizeInBytes);
4400     unsigned I = 0;
4401 
4402     // Copy words to registers.
4403     for (; I < NumRegs - LeftoverBytes; ++I, OffsetInBytes += RegSizeInBytes) {
4404       SDValue LoadPtr = DAG.getNode(ISD::ADD, DL, PtrTy, Arg,
4405                                     DAG.getConstant(OffsetInBytes, DL, PtrTy));
4406       SDValue LoadVal = DAG.getLoad(RegTy, DL, Chain, LoadPtr,
4407                                     MachinePointerInfo(), Alignment);
4408       MemOpChains.push_back(LoadVal.getValue(1));
4409       unsigned ArgReg = ArgRegs[FirstReg + I];
4410       RegsToPass.push_back(std::make_pair(ArgReg, LoadVal));
4411     }
4412 
4413     // Return if the struct has been fully copied.
4414     if (ByValSizeInBytes == OffsetInBytes)
4415       return;
4416 
4417     // Copy the remainder of the byval argument with sub-word loads and shifts.
4418     if (LeftoverBytes) {
4419       SDValue Val;
4420 
4421       for (unsigned LoadSizeInBytes = RegSizeInBytes / 2, TotalBytesLoaded = 0;
4422            OffsetInBytes < ByValSizeInBytes; LoadSizeInBytes /= 2) {
4423         unsigned RemainingSizeInBytes = ByValSizeInBytes - OffsetInBytes;
4424 
4425         if (RemainingSizeInBytes < LoadSizeInBytes)
4426           continue;
4427 
4428         // Load subword.
4429         SDValue LoadPtr = DAG.getNode(ISD::ADD, DL, PtrTy, Arg,
4430                                       DAG.getConstant(OffsetInBytes, DL,
4431                                                       PtrTy));
4432         SDValue LoadVal = DAG.getExtLoad(
4433             ISD::ZEXTLOAD, DL, RegTy, Chain, LoadPtr, MachinePointerInfo(),
4434             MVT::getIntegerVT(LoadSizeInBytes * 8), Alignment);
4435         MemOpChains.push_back(LoadVal.getValue(1));
4436 
4437         // Shift the loaded value.
4438         unsigned Shamt;
4439 
4440         if (isLittle)
4441           Shamt = TotalBytesLoaded * 8;
4442         else
4443           Shamt = (RegSizeInBytes - (TotalBytesLoaded + LoadSizeInBytes)) * 8;
4444 
4445         SDValue Shift = DAG.getNode(ISD::SHL, DL, RegTy, LoadVal,
4446                                     DAG.getConstant(Shamt, DL, MVT::i32));
4447 
4448         if (Val.getNode())
4449           Val = DAG.getNode(ISD::OR, DL, RegTy, Val, Shift);
4450         else
4451           Val = Shift;
4452 
4453         OffsetInBytes += LoadSizeInBytes;
4454         TotalBytesLoaded += LoadSizeInBytes;
4455         Alignment = std::min(Alignment, Align(LoadSizeInBytes));
4456       }
4457 
4458       unsigned ArgReg = ArgRegs[FirstReg + I];
4459       RegsToPass.push_back(std::make_pair(ArgReg, Val));
4460       return;
4461     }
4462   }
4463 
4464   // Copy remainder of byval arg to it with memcpy.
4465   unsigned MemCpySize = ByValSizeInBytes - OffsetInBytes;
4466   SDValue Src = DAG.getNode(ISD::ADD, DL, PtrTy, Arg,
4467                             DAG.getConstant(OffsetInBytes, DL, PtrTy));
4468   SDValue Dst = DAG.getNode(ISD::ADD, DL, PtrTy, StackPtr,
4469                             DAG.getIntPtrConstant(VA.getLocMemOffset(), DL));
4470   Chain = DAG.getMemcpy(
4471       Chain, DL, Dst, Src, DAG.getConstant(MemCpySize, DL, PtrTy),
4472       Align(Alignment), /*isVolatile=*/false, /*AlwaysInline=*/false,
4473       /*isTailCall=*/false, MachinePointerInfo(), MachinePointerInfo());
4474   MemOpChains.push_back(Chain);
4475 }
4476 
4477 void MipsTargetLowering::writeVarArgRegs(std::vector<SDValue> &OutChains,
4478                                          SDValue Chain, const SDLoc &DL,
4479                                          SelectionDAG &DAG,
4480                                          CCState &State) const {
4481   ArrayRef<MCPhysReg> ArgRegs = ABI.GetVarArgRegs();
4482   unsigned Idx = State.getFirstUnallocated(ArgRegs);
4483   unsigned RegSizeInBytes = Subtarget.getGPRSizeInBytes();
4484   MVT RegTy = MVT::getIntegerVT(RegSizeInBytes * 8);
4485   const TargetRegisterClass *RC = getRegClassFor(RegTy);
4486   MachineFunction &MF = DAG.getMachineFunction();
4487   MachineFrameInfo &MFI = MF.getFrameInfo();
4488   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
4489 
4490   // Offset of the first variable argument from stack pointer.
4491   int VaArgOffset;
4492 
4493   if (ArgRegs.size() == Idx)
4494     VaArgOffset = alignTo(State.getNextStackOffset(), RegSizeInBytes);
4495   else {
4496     VaArgOffset =
4497         (int)ABI.GetCalleeAllocdArgSizeInBytes(State.getCallingConv()) -
4498         (int)(RegSizeInBytes * (ArgRegs.size() - Idx));
4499   }
4500 
4501   // Record the frame index of the first variable argument
4502   // which is a value necessary to VASTART.
4503   int FI = MFI.CreateFixedObject(RegSizeInBytes, VaArgOffset, true);
4504   MipsFI->setVarArgsFrameIndex(FI);
4505 
4506   // Copy the integer registers that have not been used for argument passing
4507   // to the argument register save area. For O32, the save area is allocated
4508   // in the caller's stack frame, while for N32/64, it is allocated in the
4509   // callee's stack frame.
4510   for (unsigned I = Idx; I < ArgRegs.size();
4511        ++I, VaArgOffset += RegSizeInBytes) {
4512     unsigned Reg = addLiveIn(MF, ArgRegs[I], RC);
4513     SDValue ArgValue = DAG.getCopyFromReg(Chain, DL, Reg, RegTy);
4514     FI = MFI.CreateFixedObject(RegSizeInBytes, VaArgOffset, true);
4515     SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy(DAG.getDataLayout()));
4516     SDValue Store =
4517         DAG.getStore(Chain, DL, ArgValue, PtrOff, MachinePointerInfo());
4518     cast<StoreSDNode>(Store.getNode())->getMemOperand()->setValue(
4519         (Value *)nullptr);
4520     OutChains.push_back(Store);
4521   }
4522 }
4523 
4524 void MipsTargetLowering::HandleByVal(CCState *State, unsigned &Size,
4525                                      Align Alignment) const {
4526   const TargetFrameLowering *TFL = Subtarget.getFrameLowering();
4527 
4528   assert(Size && "Byval argument's size shouldn't be 0.");
4529 
4530   Alignment = std::min(Alignment, TFL->getStackAlign());
4531 
4532   unsigned FirstReg = 0;
4533   unsigned NumRegs = 0;
4534 
4535   if (State->getCallingConv() != CallingConv::Fast) {
4536     unsigned RegSizeInBytes = Subtarget.getGPRSizeInBytes();
4537     ArrayRef<MCPhysReg> IntArgRegs = ABI.GetByValArgRegs();
4538     // FIXME: The O32 case actually describes no shadow registers.
4539     const MCPhysReg *ShadowRegs =
4540         ABI.IsO32() ? IntArgRegs.data() : Mips64DPRegs;
4541 
4542     // We used to check the size as well but we can't do that anymore since
4543     // CCState::HandleByVal() rounds up the size after calling this function.
4544     assert(
4545         Alignment >= Align(RegSizeInBytes) &&
4546         "Byval argument's alignment should be a multiple of RegSizeInBytes.");
4547 
4548     FirstReg = State->getFirstUnallocated(IntArgRegs);
4549 
4550     // If Alignment > RegSizeInBytes, the first arg register must be even.
4551     // FIXME: This condition happens to do the right thing but it's not the
4552     //        right way to test it. We want to check that the stack frame offset
4553     //        of the register is aligned.
4554     if ((Alignment > RegSizeInBytes) && (FirstReg % 2)) {
4555       State->AllocateReg(IntArgRegs[FirstReg], ShadowRegs[FirstReg]);
4556       ++FirstReg;
4557     }
4558 
4559     // Mark the registers allocated.
4560     Size = alignTo(Size, RegSizeInBytes);
4561     for (unsigned I = FirstReg; Size > 0 && (I < IntArgRegs.size());
4562          Size -= RegSizeInBytes, ++I, ++NumRegs)
4563       State->AllocateReg(IntArgRegs[I], ShadowRegs[I]);
4564   }
4565 
4566   State->addInRegsParamInfo(FirstReg, FirstReg + NumRegs);
4567 }
4568 
4569 MachineBasicBlock *MipsTargetLowering::emitPseudoSELECT(MachineInstr &MI,
4570                                                         MachineBasicBlock *BB,
4571                                                         bool isFPCmp,
4572                                                         unsigned Opc) const {
4573   assert(!(Subtarget.hasMips4() || Subtarget.hasMips32()) &&
4574          "Subtarget already supports SELECT nodes with the use of"
4575          "conditional-move instructions.");
4576 
4577   const TargetInstrInfo *TII =
4578       Subtarget.getInstrInfo();
4579   DebugLoc DL = MI.getDebugLoc();
4580 
4581   // To "insert" a SELECT instruction, we actually have to insert the
4582   // diamond control-flow pattern.  The incoming instruction knows the
4583   // destination vreg to set, the condition code register to branch on, the
4584   // true/false values to select between, and a branch opcode to use.
4585   const BasicBlock *LLVM_BB = BB->getBasicBlock();
4586   MachineFunction::iterator It = ++BB->getIterator();
4587 
4588   //  thisMBB:
4589   //  ...
4590   //   TrueVal = ...
4591   //   setcc r1, r2, r3
4592   //   bNE   r1, r0, copy1MBB
4593   //   fallthrough --> copy0MBB
4594   MachineBasicBlock *thisMBB  = BB;
4595   MachineFunction *F = BB->getParent();
4596   MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
4597   MachineBasicBlock *sinkMBB  = F->CreateMachineBasicBlock(LLVM_BB);
4598   F->insert(It, copy0MBB);
4599   F->insert(It, sinkMBB);
4600 
4601   // Transfer the remainder of BB and its successor edges to sinkMBB.
4602   sinkMBB->splice(sinkMBB->begin(), BB,
4603                   std::next(MachineBasicBlock::iterator(MI)), BB->end());
4604   sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
4605 
4606   // Next, add the true and fallthrough blocks as its successors.
4607   BB->addSuccessor(copy0MBB);
4608   BB->addSuccessor(sinkMBB);
4609 
4610   if (isFPCmp) {
4611     // bc1[tf] cc, sinkMBB
4612     BuildMI(BB, DL, TII->get(Opc))
4613         .addReg(MI.getOperand(1).getReg())
4614         .addMBB(sinkMBB);
4615   } else {
4616     // bne rs, $0, sinkMBB
4617     BuildMI(BB, DL, TII->get(Opc))
4618         .addReg(MI.getOperand(1).getReg())
4619         .addReg(Mips::ZERO)
4620         .addMBB(sinkMBB);
4621   }
4622 
4623   //  copy0MBB:
4624   //   %FalseValue = ...
4625   //   # fallthrough to sinkMBB
4626   BB = copy0MBB;
4627 
4628   // Update machine-CFG edges
4629   BB->addSuccessor(sinkMBB);
4630 
4631   //  sinkMBB:
4632   //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
4633   //  ...
4634   BB = sinkMBB;
4635 
4636   BuildMI(*BB, BB->begin(), DL, TII->get(Mips::PHI), MI.getOperand(0).getReg())
4637       .addReg(MI.getOperand(2).getReg())
4638       .addMBB(thisMBB)
4639       .addReg(MI.getOperand(3).getReg())
4640       .addMBB(copy0MBB);
4641 
4642   MI.eraseFromParent(); // The pseudo instruction is gone now.
4643 
4644   return BB;
4645 }
4646 
4647 MachineBasicBlock *
4648 MipsTargetLowering::emitPseudoD_SELECT(MachineInstr &MI,
4649                                        MachineBasicBlock *BB) const {
4650   assert(!(Subtarget.hasMips4() || Subtarget.hasMips32()) &&
4651          "Subtarget already supports SELECT nodes with the use of"
4652          "conditional-move instructions.");
4653 
4654   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
4655   DebugLoc DL = MI.getDebugLoc();
4656 
4657   // D_SELECT substitutes two SELECT nodes that goes one after another and
4658   // have the same condition operand. On machines which don't have
4659   // conditional-move instruction, it reduces unnecessary branch instructions
4660   // which are result of using two diamond patterns that are result of two
4661   // SELECT pseudo instructions.
4662   const BasicBlock *LLVM_BB = BB->getBasicBlock();
4663   MachineFunction::iterator It = ++BB->getIterator();
4664 
4665   //  thisMBB:
4666   //  ...
4667   //   TrueVal = ...
4668   //   setcc r1, r2, r3
4669   //   bNE   r1, r0, copy1MBB
4670   //   fallthrough --> copy0MBB
4671   MachineBasicBlock *thisMBB = BB;
4672   MachineFunction *F = BB->getParent();
4673   MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
4674   MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
4675   F->insert(It, copy0MBB);
4676   F->insert(It, sinkMBB);
4677 
4678   // Transfer the remainder of BB and its successor edges to sinkMBB.
4679   sinkMBB->splice(sinkMBB->begin(), BB,
4680                   std::next(MachineBasicBlock::iterator(MI)), BB->end());
4681   sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
4682 
4683   // Next, add the true and fallthrough blocks as its successors.
4684   BB->addSuccessor(copy0MBB);
4685   BB->addSuccessor(sinkMBB);
4686 
4687   // bne rs, $0, sinkMBB
4688   BuildMI(BB, DL, TII->get(Mips::BNE))
4689       .addReg(MI.getOperand(2).getReg())
4690       .addReg(Mips::ZERO)
4691       .addMBB(sinkMBB);
4692 
4693   //  copy0MBB:
4694   //   %FalseValue = ...
4695   //   # fallthrough to sinkMBB
4696   BB = copy0MBB;
4697 
4698   // Update machine-CFG edges
4699   BB->addSuccessor(sinkMBB);
4700 
4701   //  sinkMBB:
4702   //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
4703   //  ...
4704   BB = sinkMBB;
4705 
4706   // Use two PHI nodes to select two reults
4707   BuildMI(*BB, BB->begin(), DL, TII->get(Mips::PHI), MI.getOperand(0).getReg())
4708       .addReg(MI.getOperand(3).getReg())
4709       .addMBB(thisMBB)
4710       .addReg(MI.getOperand(5).getReg())
4711       .addMBB(copy0MBB);
4712   BuildMI(*BB, BB->begin(), DL, TII->get(Mips::PHI), MI.getOperand(1).getReg())
4713       .addReg(MI.getOperand(4).getReg())
4714       .addMBB(thisMBB)
4715       .addReg(MI.getOperand(6).getReg())
4716       .addMBB(copy0MBB);
4717 
4718   MI.eraseFromParent(); // The pseudo instruction is gone now.
4719 
4720   return BB;
4721 }
4722 
4723 // FIXME? Maybe this could be a TableGen attribute on some registers and
4724 // this table could be generated automatically from RegInfo.
4725 Register
4726 MipsTargetLowering::getRegisterByName(const char *RegName, LLT VT,
4727                                       const MachineFunction &MF) const {
4728   // The Linux kernel uses $28 and sp.
4729   if (Subtarget.isGP64bit()) {
4730     Register Reg = StringSwitch<Register>(RegName)
4731                        .Case("$28", Mips::GP_64)
4732                        .Case("sp", Mips::SP_64)
4733                        .Default(Register());
4734     if (Reg)
4735       return Reg;
4736   } else {
4737     Register Reg = StringSwitch<Register>(RegName)
4738                        .Case("$28", Mips::GP)
4739                        .Case("sp", Mips::SP)
4740                        .Default(Register());
4741     if (Reg)
4742       return Reg;
4743   }
4744   report_fatal_error("Invalid register name global variable");
4745 }
4746 
4747 MachineBasicBlock *MipsTargetLowering::emitLDR_W(MachineInstr &MI,
4748                                                  MachineBasicBlock *BB) const {
4749   MachineFunction *MF = BB->getParent();
4750   MachineRegisterInfo &MRI = MF->getRegInfo();
4751   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
4752   const bool IsLittle = Subtarget.isLittle();
4753   DebugLoc DL = MI.getDebugLoc();
4754 
4755   Register Dest = MI.getOperand(0).getReg();
4756   Register Address = MI.getOperand(1).getReg();
4757   unsigned Imm = MI.getOperand(2).getImm();
4758 
4759   MachineBasicBlock::iterator I(MI);
4760 
4761   if (Subtarget.hasMips32r6() || Subtarget.hasMips64r6()) {
4762     // Mips release 6 can load from adress that is not naturally-aligned.
4763     Register Temp = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4764     BuildMI(*BB, I, DL, TII->get(Mips::LW))
4765         .addDef(Temp)
4766         .addUse(Address)
4767         .addImm(Imm);
4768     BuildMI(*BB, I, DL, TII->get(Mips::FILL_W)).addDef(Dest).addUse(Temp);
4769   } else {
4770     // Mips release 5 needs to use instructions that can load from an unaligned
4771     // memory address.
4772     Register LoadHalf = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4773     Register LoadFull = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4774     Register Undef = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4775     BuildMI(*BB, I, DL, TII->get(Mips::IMPLICIT_DEF)).addDef(Undef);
4776     BuildMI(*BB, I, DL, TII->get(Mips::LWR))
4777         .addDef(LoadHalf)
4778         .addUse(Address)
4779         .addImm(Imm + (IsLittle ? 0 : 3))
4780         .addUse(Undef);
4781     BuildMI(*BB, I, DL, TII->get(Mips::LWL))
4782         .addDef(LoadFull)
4783         .addUse(Address)
4784         .addImm(Imm + (IsLittle ? 3 : 0))
4785         .addUse(LoadHalf);
4786     BuildMI(*BB, I, DL, TII->get(Mips::FILL_W)).addDef(Dest).addUse(LoadFull);
4787   }
4788 
4789   MI.eraseFromParent();
4790   return BB;
4791 }
4792 
4793 MachineBasicBlock *MipsTargetLowering::emitLDR_D(MachineInstr &MI,
4794                                                  MachineBasicBlock *BB) const {
4795   MachineFunction *MF = BB->getParent();
4796   MachineRegisterInfo &MRI = MF->getRegInfo();
4797   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
4798   const bool IsLittle = Subtarget.isLittle();
4799   DebugLoc DL = MI.getDebugLoc();
4800 
4801   Register Dest = MI.getOperand(0).getReg();
4802   Register Address = MI.getOperand(1).getReg();
4803   unsigned Imm = MI.getOperand(2).getImm();
4804 
4805   MachineBasicBlock::iterator I(MI);
4806 
4807   if (Subtarget.hasMips32r6() || Subtarget.hasMips64r6()) {
4808     // Mips release 6 can load from adress that is not naturally-aligned.
4809     if (Subtarget.isGP64bit()) {
4810       Register Temp = MRI.createVirtualRegister(&Mips::GPR64RegClass);
4811       BuildMI(*BB, I, DL, TII->get(Mips::LD))
4812           .addDef(Temp)
4813           .addUse(Address)
4814           .addImm(Imm);
4815       BuildMI(*BB, I, DL, TII->get(Mips::FILL_D)).addDef(Dest).addUse(Temp);
4816     } else {
4817       Register Wtemp = MRI.createVirtualRegister(&Mips::MSA128WRegClass);
4818       Register Lo = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4819       Register Hi = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4820       BuildMI(*BB, I, DL, TII->get(Mips::LW))
4821           .addDef(Lo)
4822           .addUse(Address)
4823           .addImm(Imm + (IsLittle ? 0 : 4));
4824       BuildMI(*BB, I, DL, TII->get(Mips::LW))
4825           .addDef(Hi)
4826           .addUse(Address)
4827           .addImm(Imm + (IsLittle ? 4 : 0));
4828       BuildMI(*BB, I, DL, TII->get(Mips::FILL_W)).addDef(Wtemp).addUse(Lo);
4829       BuildMI(*BB, I, DL, TII->get(Mips::INSERT_W), Dest)
4830           .addUse(Wtemp)
4831           .addUse(Hi)
4832           .addImm(1);
4833     }
4834   } else {
4835     // Mips release 5 needs to use instructions that can load from an unaligned
4836     // memory address.
4837     Register LoHalf = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4838     Register LoFull = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4839     Register LoUndef = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4840     Register HiHalf = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4841     Register HiFull = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4842     Register HiUndef = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4843     Register Wtemp = MRI.createVirtualRegister(&Mips::MSA128WRegClass);
4844     BuildMI(*BB, I, DL, TII->get(Mips::IMPLICIT_DEF)).addDef(LoUndef);
4845     BuildMI(*BB, I, DL, TII->get(Mips::LWR))
4846         .addDef(LoHalf)
4847         .addUse(Address)
4848         .addImm(Imm + (IsLittle ? 0 : 7))
4849         .addUse(LoUndef);
4850     BuildMI(*BB, I, DL, TII->get(Mips::LWL))
4851         .addDef(LoFull)
4852         .addUse(Address)
4853         .addImm(Imm + (IsLittle ? 3 : 4))
4854         .addUse(LoHalf);
4855     BuildMI(*BB, I, DL, TII->get(Mips::IMPLICIT_DEF)).addDef(HiUndef);
4856     BuildMI(*BB, I, DL, TII->get(Mips::LWR))
4857         .addDef(HiHalf)
4858         .addUse(Address)
4859         .addImm(Imm + (IsLittle ? 4 : 3))
4860         .addUse(HiUndef);
4861     BuildMI(*BB, I, DL, TII->get(Mips::LWL))
4862         .addDef(HiFull)
4863         .addUse(Address)
4864         .addImm(Imm + (IsLittle ? 7 : 0))
4865         .addUse(HiHalf);
4866     BuildMI(*BB, I, DL, TII->get(Mips::FILL_W)).addDef(Wtemp).addUse(LoFull);
4867     BuildMI(*BB, I, DL, TII->get(Mips::INSERT_W), Dest)
4868         .addUse(Wtemp)
4869         .addUse(HiFull)
4870         .addImm(1);
4871   }
4872 
4873   MI.eraseFromParent();
4874   return BB;
4875 }
4876 
4877 MachineBasicBlock *MipsTargetLowering::emitSTR_W(MachineInstr &MI,
4878                                                  MachineBasicBlock *BB) const {
4879   MachineFunction *MF = BB->getParent();
4880   MachineRegisterInfo &MRI = MF->getRegInfo();
4881   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
4882   const bool IsLittle = Subtarget.isLittle();
4883   DebugLoc DL = MI.getDebugLoc();
4884 
4885   Register StoreVal = MI.getOperand(0).getReg();
4886   Register Address = MI.getOperand(1).getReg();
4887   unsigned Imm = MI.getOperand(2).getImm();
4888 
4889   MachineBasicBlock::iterator I(MI);
4890 
4891   if (Subtarget.hasMips32r6() || Subtarget.hasMips64r6()) {
4892     // Mips release 6 can store to adress that is not naturally-aligned.
4893     Register BitcastW = MRI.createVirtualRegister(&Mips::MSA128WRegClass);
4894     Register Tmp = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4895     BuildMI(*BB, I, DL, TII->get(Mips::COPY)).addDef(BitcastW).addUse(StoreVal);
4896     BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4897         .addDef(Tmp)
4898         .addUse(BitcastW)
4899         .addImm(0);
4900     BuildMI(*BB, I, DL, TII->get(Mips::SW))
4901         .addUse(Tmp)
4902         .addUse(Address)
4903         .addImm(Imm);
4904   } else {
4905     // Mips release 5 needs to use instructions that can store to an unaligned
4906     // memory address.
4907     Register Tmp = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4908     BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4909         .addDef(Tmp)
4910         .addUse(StoreVal)
4911         .addImm(0);
4912     BuildMI(*BB, I, DL, TII->get(Mips::SWR))
4913         .addUse(Tmp)
4914         .addUse(Address)
4915         .addImm(Imm + (IsLittle ? 0 : 3));
4916     BuildMI(*BB, I, DL, TII->get(Mips::SWL))
4917         .addUse(Tmp)
4918         .addUse(Address)
4919         .addImm(Imm + (IsLittle ? 3 : 0));
4920   }
4921 
4922   MI.eraseFromParent();
4923 
4924   return BB;
4925 }
4926 
4927 MachineBasicBlock *MipsTargetLowering::emitSTR_D(MachineInstr &MI,
4928                                                  MachineBasicBlock *BB) const {
4929   MachineFunction *MF = BB->getParent();
4930   MachineRegisterInfo &MRI = MF->getRegInfo();
4931   const TargetInstrInfo *TII = Subtarget.getInstrInfo();
4932   const bool IsLittle = Subtarget.isLittle();
4933   DebugLoc DL = MI.getDebugLoc();
4934 
4935   Register StoreVal = MI.getOperand(0).getReg();
4936   Register Address = MI.getOperand(1).getReg();
4937   unsigned Imm = MI.getOperand(2).getImm();
4938 
4939   MachineBasicBlock::iterator I(MI);
4940 
4941   if (Subtarget.hasMips32r6() || Subtarget.hasMips64r6()) {
4942     // Mips release 6 can store to adress that is not naturally-aligned.
4943     if (Subtarget.isGP64bit()) {
4944       Register BitcastD = MRI.createVirtualRegister(&Mips::MSA128DRegClass);
4945       Register Lo = MRI.createVirtualRegister(&Mips::GPR64RegClass);
4946       BuildMI(*BB, I, DL, TII->get(Mips::COPY))
4947           .addDef(BitcastD)
4948           .addUse(StoreVal);
4949       BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_D))
4950           .addDef(Lo)
4951           .addUse(BitcastD)
4952           .addImm(0);
4953       BuildMI(*BB, I, DL, TII->get(Mips::SD))
4954           .addUse(Lo)
4955           .addUse(Address)
4956           .addImm(Imm);
4957     } else {
4958       Register BitcastW = MRI.createVirtualRegister(&Mips::MSA128WRegClass);
4959       Register Lo = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4960       Register Hi = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4961       BuildMI(*BB, I, DL, TII->get(Mips::COPY))
4962           .addDef(BitcastW)
4963           .addUse(StoreVal);
4964       BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4965           .addDef(Lo)
4966           .addUse(BitcastW)
4967           .addImm(0);
4968       BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4969           .addDef(Hi)
4970           .addUse(BitcastW)
4971           .addImm(1);
4972       BuildMI(*BB, I, DL, TII->get(Mips::SW))
4973           .addUse(Lo)
4974           .addUse(Address)
4975           .addImm(Imm + (IsLittle ? 0 : 4));
4976       BuildMI(*BB, I, DL, TII->get(Mips::SW))
4977           .addUse(Hi)
4978           .addUse(Address)
4979           .addImm(Imm + (IsLittle ? 4 : 0));
4980     }
4981   } else {
4982     // Mips release 5 needs to use instructions that can store to an unaligned
4983     // memory address.
4984     Register Bitcast = MRI.createVirtualRegister(&Mips::MSA128WRegClass);
4985     Register Lo = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4986     Register Hi = MRI.createVirtualRegister(&Mips::GPR32RegClass);
4987     BuildMI(*BB, I, DL, TII->get(Mips::COPY)).addDef(Bitcast).addUse(StoreVal);
4988     BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4989         .addDef(Lo)
4990         .addUse(Bitcast)
4991         .addImm(0);
4992     BuildMI(*BB, I, DL, TII->get(Mips::COPY_S_W))
4993         .addDef(Hi)
4994         .addUse(Bitcast)
4995         .addImm(1);
4996     BuildMI(*BB, I, DL, TII->get(Mips::SWR))
4997         .addUse(Lo)
4998         .addUse(Address)
4999         .addImm(Imm + (IsLittle ? 0 : 3));
5000     BuildMI(*BB, I, DL, TII->get(Mips::SWL))
5001         .addUse(Lo)
5002         .addUse(Address)
5003         .addImm(Imm + (IsLittle ? 3 : 0));
5004     BuildMI(*BB, I, DL, TII->get(Mips::SWR))
5005         .addUse(Hi)
5006         .addUse(Address)
5007         .addImm(Imm + (IsLittle ? 4 : 7));
5008     BuildMI(*BB, I, DL, TII->get(Mips::SWL))
5009         .addUse(Hi)
5010         .addUse(Address)
5011         .addImm(Imm + (IsLittle ? 7 : 4));
5012   }
5013 
5014   MI.eraseFromParent();
5015   return BB;
5016 }
5017