1 //===- ARCISelDAGToDAG.cpp - ARC dag to dag inst selector -------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines an instruction selector for the ARC target.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "ARC.h"
15 #include "ARCTargetMachine.h"
16 #include "llvm/CodeGen/MachineFrameInfo.h"
17 #include "llvm/CodeGen/MachineFunction.h"
18 #include "llvm/CodeGen/MachineInstrBuilder.h"
19 #include "llvm/CodeGen/MachineRegisterInfo.h"
20 #include "llvm/CodeGen/SelectionDAG.h"
21 #include "llvm/CodeGen/SelectionDAGISel.h"
22 #include "llvm/CodeGen/TargetLowering.h"
23 #include "llvm/IR/CallingConv.h"
24 #include "llvm/IR/Constants.h"
25 #include "llvm/IR/DerivedTypes.h"
26 #include "llvm/IR/Function.h"
27 #include "llvm/IR/Intrinsics.h"
28 #include "llvm/IR/LLVMContext.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/raw_ostream.h"
33 
34 using namespace llvm;
35 
36 /// ARCDAGToDAGISel - ARC specific code to select ARC machine
37 /// instructions for SelectionDAG operations.
38 namespace {
39 
40 class ARCDAGToDAGISel : public SelectionDAGISel {
41 public:
42   ARCDAGToDAGISel(ARCTargetMachine &TM, CodeGenOpt::Level OptLevel)
43       : SelectionDAGISel(TM, OptLevel) {}
44 
45   void Select(SDNode *N) override;
46 
47   // Complex Pattern Selectors.
48   bool SelectFrameADDR_ri(SDValue Addr, SDValue &Base, SDValue &Offset);
49   bool SelectAddrModeS9(SDValue Addr, SDValue &Base, SDValue &Offset);
50   bool SelectAddrModeImm(SDValue Addr, SDValue &Base, SDValue &Offset);
51   bool SelectAddrModeFar(SDValue Addr, SDValue &Base, SDValue &Offset);
52   bool SelectCMOVPred(SDValue N, SDValue &Pred, SDValue &Reg) {
53     const ConstantSDNode *CN = cast<ConstantSDNode>(N);
54     Pred = CurDAG->getTargetConstant(CN->getZExtValue(), SDLoc(N), MVT::i32);
55     Reg = CurDAG->getRegister(ARC::STATUS32, MVT::i32);
56     return true;
57   }
58 
59   StringRef getPassName() const override {
60     return "ARC DAG->DAG Pattern Instruction Selection";
61   }
62 
63 // Include the pieces autogenerated from the target description.
64 #include "ARCGenDAGISel.inc"
65 };
66 
67 } // end anonymous namespace
68 
69 /// This pass converts a legalized DAG into a ARC-specific DAG, ready for
70 /// instruction scheduling.
71 FunctionPass *llvm::createARCISelDag(ARCTargetMachine &TM,
72                                      CodeGenOpt::Level OptLevel) {
73   return new ARCDAGToDAGISel(TM, OptLevel);
74 }
75 
76 bool ARCDAGToDAGISel::SelectAddrModeImm(SDValue Addr, SDValue &Base,
77                                         SDValue &Offset) {
78   if (Addr.getOpcode() == ARCISD::GAWRAPPER) {
79     Base = Addr.getOperand(0);
80     Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
81     return true;
82   }
83   return false;
84 }
85 
86 bool ARCDAGToDAGISel::SelectAddrModeS9(SDValue Addr, SDValue &Base,
87                                        SDValue &Offset) {
88   if (Addr.getOpcode() == ARCISD::GAWRAPPER) {
89     return false;
90   }
91 
92   if (Addr.getOpcode() != ISD::ADD && Addr.getOpcode() != ISD::SUB &&
93       !CurDAG->isBaseWithConstantOffset(Addr)) {
94     if (Addr.getOpcode() == ISD::FrameIndex) {
95       // Match frame index.
96       int FI = cast<FrameIndexSDNode>(Addr)->getIndex();
97       Base = CurDAG->getTargetFrameIndex(
98           FI, TLI->getPointerTy(CurDAG->getDataLayout()));
99     } else {
100       Base = Addr;
101     }
102     Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
103     return true;
104   }
105 
106   if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
107     int32_t RHSC = RHS->getSExtValue();
108     if (Addr.getOpcode() == ISD::SUB)
109       RHSC = -RHSC;
110 
111     // Do we need more than 9 bits to encode?
112     if (!isInt<9>(RHSC))
113       return false;
114     Base = Addr.getOperand(0);
115     if (Base.getOpcode() == ISD::FrameIndex) {
116       int FI = cast<FrameIndexSDNode>(Base)->getIndex();
117       Base = CurDAG->getTargetFrameIndex(
118           FI, TLI->getPointerTy(CurDAG->getDataLayout()));
119     }
120     Offset = CurDAG->getTargetConstant(RHSC, SDLoc(Addr), MVT::i32);
121     return true;
122   }
123   Base = Addr;
124   Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
125   return true;
126 }
127 
128 bool ARCDAGToDAGISel::SelectAddrModeFar(SDValue Addr, SDValue &Base,
129                                         SDValue &Offset) {
130   if (SelectAddrModeS9(Addr, Base, Offset))
131     return false;
132   if (Addr.getOpcode() == ARCISD::GAWRAPPER) {
133     return false;
134   }
135   if (ConstantSDNode *RHS = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
136     int32_t RHSC = RHS->getSExtValue();
137     if (Addr.getOpcode() == ISD::SUB)
138       RHSC = -RHSC;
139     Base = Addr.getOperand(0);
140     Offset = CurDAG->getTargetConstant(RHSC, SDLoc(Addr), MVT::i32);
141     return true;
142   }
143   return false;
144 }
145 
146 // Is this a legal frame index addressing expression.
147 bool ARCDAGToDAGISel::SelectFrameADDR_ri(SDValue Addr, SDValue &Base,
148                                          SDValue &Offset) {
149   FrameIndexSDNode *FIN = nullptr;
150   if ((FIN = dyn_cast<FrameIndexSDNode>(Addr))) {
151     Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
152     Offset = CurDAG->getTargetConstant(0, SDLoc(Addr), MVT::i32);
153     return true;
154   }
155   if (Addr.getOpcode() == ISD::ADD) {
156     ConstantSDNode *CN = nullptr;
157     if ((FIN = dyn_cast<FrameIndexSDNode>(Addr.getOperand(0))) &&
158         (CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) &&
159         (CN->getSExtValue() % 4 == 0 && CN->getSExtValue() >= 0)) {
160       // Constant positive word offset from frame index
161       Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
162       Offset =
163           CurDAG->getTargetConstant(CN->getSExtValue(), SDLoc(Addr), MVT::i32);
164       return true;
165     }
166   }
167   return false;
168 }
169 
170 void ARCDAGToDAGISel::Select(SDNode *N) {
171   switch (N->getOpcode()) {
172   case ISD::Constant: {
173     uint64_t CVal = cast<ConstantSDNode>(N)->getZExtValue();
174     ReplaceNode(N, CurDAG->getMachineNode(
175                        isInt<12>(CVal) ? ARC::MOV_rs12 : ARC::MOV_rlimm,
176                        SDLoc(N), MVT::i32,
177                        CurDAG->getTargetConstant(CVal, SDLoc(N), MVT::i32)));
178     return;
179   }
180   }
181   SelectCode(N);
182 }
183