1 //===- TargetLoweringBase.cpp - Implement the TargetLoweringBase class ----===//
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 implements the TargetLoweringBase class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/ADT/BitVector.h"
14 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/Analysis/Loads.h"
21 #include "llvm/Analysis/TargetTransformInfo.h"
22 #include "llvm/CodeGen/Analysis.h"
23 #include "llvm/CodeGen/ISDOpcodes.h"
24 #include "llvm/CodeGen/MachineBasicBlock.h"
25 #include "llvm/CodeGen/MachineFrameInfo.h"
26 #include "llvm/CodeGen/MachineFunction.h"
27 #include "llvm/CodeGen/MachineInstr.h"
28 #include "llvm/CodeGen/MachineInstrBuilder.h"
29 #include "llvm/CodeGen/MachineMemOperand.h"
30 #include "llvm/CodeGen/MachineOperand.h"
31 #include "llvm/CodeGen/MachineRegisterInfo.h"
32 #include "llvm/CodeGen/RuntimeLibcalls.h"
33 #include "llvm/CodeGen/StackMaps.h"
34 #include "llvm/CodeGen/TargetLowering.h"
35 #include "llvm/CodeGen/TargetOpcodes.h"
36 #include "llvm/CodeGen/TargetRegisterInfo.h"
37 #include "llvm/CodeGen/ValueTypes.h"
38 #include "llvm/IR/Attributes.h"
39 #include "llvm/IR/CallingConv.h"
40 #include "llvm/IR/DataLayout.h"
41 #include "llvm/IR/DerivedTypes.h"
42 #include "llvm/IR/Function.h"
43 #include "llvm/IR/GlobalValue.h"
44 #include "llvm/IR/GlobalVariable.h"
45 #include "llvm/IR/IRBuilder.h"
46 #include "llvm/IR/Module.h"
47 #include "llvm/IR/Type.h"
48 #include "llvm/Support/Casting.h"
49 #include "llvm/Support/CommandLine.h"
50 #include "llvm/Support/Compiler.h"
51 #include "llvm/Support/ErrorHandling.h"
52 #include "llvm/Support/MachineValueType.h"
53 #include "llvm/Support/MathExtras.h"
54 #include "llvm/Target/TargetMachine.h"
55 #include "llvm/Target/TargetOptions.h"
56 #include "llvm/Transforms/Utils/SizeOpts.h"
57 #include <algorithm>
58 #include <cassert>
59 #include <cstddef>
60 #include <cstdint>
61 #include <cstring>
62 #include <iterator>
63 #include <string>
64 #include <tuple>
65 #include <utility>
66 
67 using namespace llvm;
68 
69 static cl::opt<bool> JumpIsExpensiveOverride(
70     "jump-is-expensive", cl::init(false),
71     cl::desc("Do not create extra branches to split comparison logic."),
72     cl::Hidden);
73 
74 static cl::opt<unsigned> MinimumJumpTableEntries
75   ("min-jump-table-entries", cl::init(4), cl::Hidden,
76    cl::desc("Set minimum number of entries to use a jump table."));
77 
78 static cl::opt<unsigned> MaximumJumpTableSize
79   ("max-jump-table-size", cl::init(UINT_MAX), cl::Hidden,
80    cl::desc("Set maximum size of jump tables."));
81 
82 /// Minimum jump table density for normal functions.
83 static cl::opt<unsigned>
84     JumpTableDensity("jump-table-density", cl::init(10), cl::Hidden,
85                      cl::desc("Minimum density for building a jump table in "
86                               "a normal function"));
87 
88 /// Minimum jump table density for -Os or -Oz functions.
89 static cl::opt<unsigned> OptsizeJumpTableDensity(
90     "optsize-jump-table-density", cl::init(40), cl::Hidden,
91     cl::desc("Minimum density for building a jump table in "
92              "an optsize function"));
93 
94 // FIXME: This option is only to test if the strict fp operation processed
95 // correctly by preventing mutating strict fp operation to normal fp operation
96 // during development. When the backend supports strict float operation, this
97 // option will be meaningless.
98 static cl::opt<bool> DisableStrictNodeMutation("disable-strictnode-mutation",
99        cl::desc("Don't mutate strict-float node to a legalize node"),
100        cl::init(false), cl::Hidden);
101 
102 static bool darwinHasSinCos(const Triple &TT) {
103   assert(TT.isOSDarwin() && "should be called with darwin triple");
104   // Don't bother with 32 bit x86.
105   if (TT.getArch() == Triple::x86)
106     return false;
107   // Macos < 10.9 has no sincos_stret.
108   if (TT.isMacOSX())
109     return !TT.isMacOSXVersionLT(10, 9) && TT.isArch64Bit();
110   // iOS < 7.0 has no sincos_stret.
111   if (TT.isiOS())
112     return !TT.isOSVersionLT(7, 0);
113   // Any other darwin such as WatchOS/TvOS is new enough.
114   return true;
115 }
116 
117 void TargetLoweringBase::InitLibcalls(const Triple &TT) {
118 #define HANDLE_LIBCALL(code, name) \
119   setLibcallName(RTLIB::code, name);
120 #include "llvm/IR/RuntimeLibcalls.def"
121 #undef HANDLE_LIBCALL
122   // Initialize calling conventions to their default.
123   for (int LC = 0; LC < RTLIB::UNKNOWN_LIBCALL; ++LC)
124     setLibcallCallingConv((RTLIB::Libcall)LC, CallingConv::C);
125 
126   // For IEEE quad-precision libcall names, PPC uses "kf" instead of "tf".
127   if (TT.isPPC()) {
128     setLibcallName(RTLIB::ADD_F128, "__addkf3");
129     setLibcallName(RTLIB::SUB_F128, "__subkf3");
130     setLibcallName(RTLIB::MUL_F128, "__mulkf3");
131     setLibcallName(RTLIB::DIV_F128, "__divkf3");
132     setLibcallName(RTLIB::POWI_F128, "__powikf2");
133     setLibcallName(RTLIB::FPEXT_F32_F128, "__extendsfkf2");
134     setLibcallName(RTLIB::FPEXT_F64_F128, "__extenddfkf2");
135     setLibcallName(RTLIB::FPROUND_F128_F32, "__trunckfsf2");
136     setLibcallName(RTLIB::FPROUND_F128_F64, "__trunckfdf2");
137     setLibcallName(RTLIB::FPTOSINT_F128_I32, "__fixkfsi");
138     setLibcallName(RTLIB::FPTOSINT_F128_I64, "__fixkfdi");
139     setLibcallName(RTLIB::FPTOSINT_F128_I128, "__fixkfti");
140     setLibcallName(RTLIB::FPTOUINT_F128_I32, "__fixunskfsi");
141     setLibcallName(RTLIB::FPTOUINT_F128_I64, "__fixunskfdi");
142     setLibcallName(RTLIB::FPTOUINT_F128_I128, "__fixunskfti");
143     setLibcallName(RTLIB::SINTTOFP_I32_F128, "__floatsikf");
144     setLibcallName(RTLIB::SINTTOFP_I64_F128, "__floatdikf");
145     setLibcallName(RTLIB::SINTTOFP_I128_F128, "__floattikf");
146     setLibcallName(RTLIB::UINTTOFP_I32_F128, "__floatunsikf");
147     setLibcallName(RTLIB::UINTTOFP_I64_F128, "__floatundikf");
148     setLibcallName(RTLIB::UINTTOFP_I128_F128, "__floatuntikf");
149     setLibcallName(RTLIB::OEQ_F128, "__eqkf2");
150     setLibcallName(RTLIB::UNE_F128, "__nekf2");
151     setLibcallName(RTLIB::OGE_F128, "__gekf2");
152     setLibcallName(RTLIB::OLT_F128, "__ltkf2");
153     setLibcallName(RTLIB::OLE_F128, "__lekf2");
154     setLibcallName(RTLIB::OGT_F128, "__gtkf2");
155     setLibcallName(RTLIB::UO_F128, "__unordkf2");
156   }
157 
158   // A few names are different on particular architectures or environments.
159   if (TT.isOSDarwin()) {
160     // For f16/f32 conversions, Darwin uses the standard naming scheme, instead
161     // of the gnueabi-style __gnu_*_ieee.
162     // FIXME: What about other targets?
163     setLibcallName(RTLIB::FPEXT_F16_F32, "__extendhfsf2");
164     setLibcallName(RTLIB::FPROUND_F32_F16, "__truncsfhf2");
165 
166     // Some darwins have an optimized __bzero/bzero function.
167     switch (TT.getArch()) {
168     case Triple::x86:
169     case Triple::x86_64:
170       if (TT.isMacOSX() && !TT.isMacOSXVersionLT(10, 6))
171         setLibcallName(RTLIB::BZERO, "__bzero");
172       break;
173     case Triple::aarch64:
174     case Triple::aarch64_32:
175       setLibcallName(RTLIB::BZERO, "bzero");
176       break;
177     default:
178       break;
179     }
180 
181     if (darwinHasSinCos(TT)) {
182       setLibcallName(RTLIB::SINCOS_STRET_F32, "__sincosf_stret");
183       setLibcallName(RTLIB::SINCOS_STRET_F64, "__sincos_stret");
184       if (TT.isWatchABI()) {
185         setLibcallCallingConv(RTLIB::SINCOS_STRET_F32,
186                               CallingConv::ARM_AAPCS_VFP);
187         setLibcallCallingConv(RTLIB::SINCOS_STRET_F64,
188                               CallingConv::ARM_AAPCS_VFP);
189       }
190     }
191   } else {
192     setLibcallName(RTLIB::FPEXT_F16_F32, "__gnu_h2f_ieee");
193     setLibcallName(RTLIB::FPROUND_F32_F16, "__gnu_f2h_ieee");
194   }
195 
196   if (TT.isGNUEnvironment() || TT.isOSFuchsia() ||
197       (TT.isAndroid() && !TT.isAndroidVersionLT(9))) {
198     setLibcallName(RTLIB::SINCOS_F32, "sincosf");
199     setLibcallName(RTLIB::SINCOS_F64, "sincos");
200     setLibcallName(RTLIB::SINCOS_F80, "sincosl");
201     setLibcallName(RTLIB::SINCOS_F128, "sincosl");
202     setLibcallName(RTLIB::SINCOS_PPCF128, "sincosl");
203   }
204 
205   if (TT.isPS4CPU()) {
206     setLibcallName(RTLIB::SINCOS_F32, "sincosf");
207     setLibcallName(RTLIB::SINCOS_F64, "sincos");
208   }
209 
210   if (TT.isOSOpenBSD()) {
211     setLibcallName(RTLIB::STACKPROTECTOR_CHECK_FAIL, nullptr);
212   }
213 }
214 
215 /// GetFPLibCall - Helper to return the right libcall for the given floating
216 /// point type, or UNKNOWN_LIBCALL if there is none.
217 RTLIB::Libcall RTLIB::getFPLibCall(EVT VT,
218                                    RTLIB::Libcall Call_F32,
219                                    RTLIB::Libcall Call_F64,
220                                    RTLIB::Libcall Call_F80,
221                                    RTLIB::Libcall Call_F128,
222                                    RTLIB::Libcall Call_PPCF128) {
223   return
224     VT == MVT::f32 ? Call_F32 :
225     VT == MVT::f64 ? Call_F64 :
226     VT == MVT::f80 ? Call_F80 :
227     VT == MVT::f128 ? Call_F128 :
228     VT == MVT::ppcf128 ? Call_PPCF128 :
229     RTLIB::UNKNOWN_LIBCALL;
230 }
231 
232 /// getFPEXT - Return the FPEXT_*_* value for the given types, or
233 /// UNKNOWN_LIBCALL if there is none.
234 RTLIB::Libcall RTLIB::getFPEXT(EVT OpVT, EVT RetVT) {
235   if (OpVT == MVT::f16) {
236     if (RetVT == MVT::f32)
237       return FPEXT_F16_F32;
238     if (RetVT == MVT::f64)
239       return FPEXT_F16_F64;
240     if (RetVT == MVT::f80)
241       return FPEXT_F16_F80;
242     if (RetVT == MVT::f128)
243       return FPEXT_F16_F128;
244   } else if (OpVT == MVT::f32) {
245     if (RetVT == MVT::f64)
246       return FPEXT_F32_F64;
247     if (RetVT == MVT::f128)
248       return FPEXT_F32_F128;
249     if (RetVT == MVT::ppcf128)
250       return FPEXT_F32_PPCF128;
251   } else if (OpVT == MVT::f64) {
252     if (RetVT == MVT::f128)
253       return FPEXT_F64_F128;
254     else if (RetVT == MVT::ppcf128)
255       return FPEXT_F64_PPCF128;
256   } else if (OpVT == MVT::f80) {
257     if (RetVT == MVT::f128)
258       return FPEXT_F80_F128;
259   }
260 
261   return UNKNOWN_LIBCALL;
262 }
263 
264 /// getFPROUND - Return the FPROUND_*_* value for the given types, or
265 /// UNKNOWN_LIBCALL if there is none.
266 RTLIB::Libcall RTLIB::getFPROUND(EVT OpVT, EVT RetVT) {
267   if (RetVT == MVT::f16) {
268     if (OpVT == MVT::f32)
269       return FPROUND_F32_F16;
270     if (OpVT == MVT::f64)
271       return FPROUND_F64_F16;
272     if (OpVT == MVT::f80)
273       return FPROUND_F80_F16;
274     if (OpVT == MVT::f128)
275       return FPROUND_F128_F16;
276     if (OpVT == MVT::ppcf128)
277       return FPROUND_PPCF128_F16;
278   } else if (RetVT == MVT::f32) {
279     if (OpVT == MVT::f64)
280       return FPROUND_F64_F32;
281     if (OpVT == MVT::f80)
282       return FPROUND_F80_F32;
283     if (OpVT == MVT::f128)
284       return FPROUND_F128_F32;
285     if (OpVT == MVT::ppcf128)
286       return FPROUND_PPCF128_F32;
287   } else if (RetVT == MVT::f64) {
288     if (OpVT == MVT::f80)
289       return FPROUND_F80_F64;
290     if (OpVT == MVT::f128)
291       return FPROUND_F128_F64;
292     if (OpVT == MVT::ppcf128)
293       return FPROUND_PPCF128_F64;
294   } else if (RetVT == MVT::f80) {
295     if (OpVT == MVT::f128)
296       return FPROUND_F128_F80;
297   }
298 
299   return UNKNOWN_LIBCALL;
300 }
301 
302 /// getFPTOSINT - Return the FPTOSINT_*_* value for the given types, or
303 /// UNKNOWN_LIBCALL if there is none.
304 RTLIB::Libcall RTLIB::getFPTOSINT(EVT OpVT, EVT RetVT) {
305   if (OpVT == MVT::f16) {
306     if (RetVT == MVT::i32)
307       return FPTOSINT_F16_I32;
308     if (RetVT == MVT::i64)
309       return FPTOSINT_F16_I64;
310     if (RetVT == MVT::i128)
311       return FPTOSINT_F16_I128;
312   } else if (OpVT == MVT::f32) {
313     if (RetVT == MVT::i32)
314       return FPTOSINT_F32_I32;
315     if (RetVT == MVT::i64)
316       return FPTOSINT_F32_I64;
317     if (RetVT == MVT::i128)
318       return FPTOSINT_F32_I128;
319   } else if (OpVT == MVT::f64) {
320     if (RetVT == MVT::i32)
321       return FPTOSINT_F64_I32;
322     if (RetVT == MVT::i64)
323       return FPTOSINT_F64_I64;
324     if (RetVT == MVT::i128)
325       return FPTOSINT_F64_I128;
326   } else if (OpVT == MVT::f80) {
327     if (RetVT == MVT::i32)
328       return FPTOSINT_F80_I32;
329     if (RetVT == MVT::i64)
330       return FPTOSINT_F80_I64;
331     if (RetVT == MVT::i128)
332       return FPTOSINT_F80_I128;
333   } else if (OpVT == MVT::f128) {
334     if (RetVT == MVT::i32)
335       return FPTOSINT_F128_I32;
336     if (RetVT == MVT::i64)
337       return FPTOSINT_F128_I64;
338     if (RetVT == MVT::i128)
339       return FPTOSINT_F128_I128;
340   } else if (OpVT == MVT::ppcf128) {
341     if (RetVT == MVT::i32)
342       return FPTOSINT_PPCF128_I32;
343     if (RetVT == MVT::i64)
344       return FPTOSINT_PPCF128_I64;
345     if (RetVT == MVT::i128)
346       return FPTOSINT_PPCF128_I128;
347   }
348   return UNKNOWN_LIBCALL;
349 }
350 
351 /// getFPTOUINT - Return the FPTOUINT_*_* value for the given types, or
352 /// UNKNOWN_LIBCALL if there is none.
353 RTLIB::Libcall RTLIB::getFPTOUINT(EVT OpVT, EVT RetVT) {
354   if (OpVT == MVT::f16) {
355     if (RetVT == MVT::i32)
356       return FPTOUINT_F16_I32;
357     if (RetVT == MVT::i64)
358       return FPTOUINT_F16_I64;
359     if (RetVT == MVT::i128)
360       return FPTOUINT_F16_I128;
361   } else if (OpVT == MVT::f32) {
362     if (RetVT == MVT::i32)
363       return FPTOUINT_F32_I32;
364     if (RetVT == MVT::i64)
365       return FPTOUINT_F32_I64;
366     if (RetVT == MVT::i128)
367       return FPTOUINT_F32_I128;
368   } else if (OpVT == MVT::f64) {
369     if (RetVT == MVT::i32)
370       return FPTOUINT_F64_I32;
371     if (RetVT == MVT::i64)
372       return FPTOUINT_F64_I64;
373     if (RetVT == MVT::i128)
374       return FPTOUINT_F64_I128;
375   } else if (OpVT == MVT::f80) {
376     if (RetVT == MVT::i32)
377       return FPTOUINT_F80_I32;
378     if (RetVT == MVT::i64)
379       return FPTOUINT_F80_I64;
380     if (RetVT == MVT::i128)
381       return FPTOUINT_F80_I128;
382   } else if (OpVT == MVT::f128) {
383     if (RetVT == MVT::i32)
384       return FPTOUINT_F128_I32;
385     if (RetVT == MVT::i64)
386       return FPTOUINT_F128_I64;
387     if (RetVT == MVT::i128)
388       return FPTOUINT_F128_I128;
389   } else if (OpVT == MVT::ppcf128) {
390     if (RetVT == MVT::i32)
391       return FPTOUINT_PPCF128_I32;
392     if (RetVT == MVT::i64)
393       return FPTOUINT_PPCF128_I64;
394     if (RetVT == MVT::i128)
395       return FPTOUINT_PPCF128_I128;
396   }
397   return UNKNOWN_LIBCALL;
398 }
399 
400 /// getSINTTOFP - Return the SINTTOFP_*_* value for the given types, or
401 /// UNKNOWN_LIBCALL if there is none.
402 RTLIB::Libcall RTLIB::getSINTTOFP(EVT OpVT, EVT RetVT) {
403   if (OpVT == MVT::i32) {
404     if (RetVT == MVT::f16)
405       return SINTTOFP_I32_F16;
406     if (RetVT == MVT::f32)
407       return SINTTOFP_I32_F32;
408     if (RetVT == MVT::f64)
409       return SINTTOFP_I32_F64;
410     if (RetVT == MVT::f80)
411       return SINTTOFP_I32_F80;
412     if (RetVT == MVT::f128)
413       return SINTTOFP_I32_F128;
414     if (RetVT == MVT::ppcf128)
415       return SINTTOFP_I32_PPCF128;
416   } else if (OpVT == MVT::i64) {
417     if (RetVT == MVT::f16)
418       return SINTTOFP_I64_F16;
419     if (RetVT == MVT::f32)
420       return SINTTOFP_I64_F32;
421     if (RetVT == MVT::f64)
422       return SINTTOFP_I64_F64;
423     if (RetVT == MVT::f80)
424       return SINTTOFP_I64_F80;
425     if (RetVT == MVT::f128)
426       return SINTTOFP_I64_F128;
427     if (RetVT == MVT::ppcf128)
428       return SINTTOFP_I64_PPCF128;
429   } else if (OpVT == MVT::i128) {
430     if (RetVT == MVT::f16)
431       return SINTTOFP_I128_F16;
432     if (RetVT == MVT::f32)
433       return SINTTOFP_I128_F32;
434     if (RetVT == MVT::f64)
435       return SINTTOFP_I128_F64;
436     if (RetVT == MVT::f80)
437       return SINTTOFP_I128_F80;
438     if (RetVT == MVT::f128)
439       return SINTTOFP_I128_F128;
440     if (RetVT == MVT::ppcf128)
441       return SINTTOFP_I128_PPCF128;
442   }
443   return UNKNOWN_LIBCALL;
444 }
445 
446 /// getUINTTOFP - Return the UINTTOFP_*_* value for the given types, or
447 /// UNKNOWN_LIBCALL if there is none.
448 RTLIB::Libcall RTLIB::getUINTTOFP(EVT OpVT, EVT RetVT) {
449   if (OpVT == MVT::i32) {
450     if (RetVT == MVT::f16)
451       return UINTTOFP_I32_F16;
452     if (RetVT == MVT::f32)
453       return UINTTOFP_I32_F32;
454     if (RetVT == MVT::f64)
455       return UINTTOFP_I32_F64;
456     if (RetVT == MVT::f80)
457       return UINTTOFP_I32_F80;
458     if (RetVT == MVT::f128)
459       return UINTTOFP_I32_F128;
460     if (RetVT == MVT::ppcf128)
461       return UINTTOFP_I32_PPCF128;
462   } else if (OpVT == MVT::i64) {
463     if (RetVT == MVT::f16)
464       return UINTTOFP_I64_F16;
465     if (RetVT == MVT::f32)
466       return UINTTOFP_I64_F32;
467     if (RetVT == MVT::f64)
468       return UINTTOFP_I64_F64;
469     if (RetVT == MVT::f80)
470       return UINTTOFP_I64_F80;
471     if (RetVT == MVT::f128)
472       return UINTTOFP_I64_F128;
473     if (RetVT == MVT::ppcf128)
474       return UINTTOFP_I64_PPCF128;
475   } else if (OpVT == MVT::i128) {
476     if (RetVT == MVT::f16)
477       return UINTTOFP_I128_F16;
478     if (RetVT == MVT::f32)
479       return UINTTOFP_I128_F32;
480     if (RetVT == MVT::f64)
481       return UINTTOFP_I128_F64;
482     if (RetVT == MVT::f80)
483       return UINTTOFP_I128_F80;
484     if (RetVT == MVT::f128)
485       return UINTTOFP_I128_F128;
486     if (RetVT == MVT::ppcf128)
487       return UINTTOFP_I128_PPCF128;
488   }
489   return UNKNOWN_LIBCALL;
490 }
491 
492 RTLIB::Libcall RTLIB::getPOWI(EVT RetVT) {
493   return getFPLibCall(RetVT, POWI_F32, POWI_F64, POWI_F80, POWI_F128,
494                       POWI_PPCF128);
495 }
496 
497 RTLIB::Libcall RTLIB::getOUTLINE_ATOMIC(unsigned Opc, AtomicOrdering Order,
498                                         MVT VT) {
499   unsigned ModeN, ModelN;
500   switch (VT.SimpleTy) {
501   case MVT::i8:
502     ModeN = 0;
503     break;
504   case MVT::i16:
505     ModeN = 1;
506     break;
507   case MVT::i32:
508     ModeN = 2;
509     break;
510   case MVT::i64:
511     ModeN = 3;
512     break;
513   case MVT::i128:
514     ModeN = 4;
515     break;
516   default:
517     return UNKNOWN_LIBCALL;
518   }
519 
520   switch (Order) {
521   case AtomicOrdering::Monotonic:
522     ModelN = 0;
523     break;
524   case AtomicOrdering::Acquire:
525     ModelN = 1;
526     break;
527   case AtomicOrdering::Release:
528     ModelN = 2;
529     break;
530   case AtomicOrdering::AcquireRelease:
531   case AtomicOrdering::SequentiallyConsistent:
532     ModelN = 3;
533     break;
534   default:
535     return UNKNOWN_LIBCALL;
536   }
537 
538 #define LCALLS(A, B)                                                           \
539   { A##B##_RELAX, A##B##_ACQ, A##B##_REL, A##B##_ACQ_REL }
540 #define LCALL5(A)                                                              \
541   LCALLS(A, 1), LCALLS(A, 2), LCALLS(A, 4), LCALLS(A, 8), LCALLS(A, 16)
542   switch (Opc) {
543   case ISD::ATOMIC_CMP_SWAP: {
544     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_CAS)};
545     return LC[ModeN][ModelN];
546   }
547   case ISD::ATOMIC_SWAP: {
548     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_SWP)};
549     return LC[ModeN][ModelN];
550   }
551   case ISD::ATOMIC_LOAD_ADD: {
552     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_LDADD)};
553     return LC[ModeN][ModelN];
554   }
555   case ISD::ATOMIC_LOAD_OR: {
556     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_LDSET)};
557     return LC[ModeN][ModelN];
558   }
559   case ISD::ATOMIC_LOAD_CLR: {
560     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_LDCLR)};
561     return LC[ModeN][ModelN];
562   }
563   case ISD::ATOMIC_LOAD_XOR: {
564     const Libcall LC[5][4] = {LCALL5(OUTLINE_ATOMIC_LDEOR)};
565     return LC[ModeN][ModelN];
566   }
567   default:
568     return UNKNOWN_LIBCALL;
569   }
570 #undef LCALLS
571 #undef LCALL5
572 }
573 
574 RTLIB::Libcall RTLIB::getSYNC(unsigned Opc, MVT VT) {
575 #define OP_TO_LIBCALL(Name, Enum)                                              \
576   case Name:                                                                   \
577     switch (VT.SimpleTy) {                                                     \
578     default:                                                                   \
579       return UNKNOWN_LIBCALL;                                                  \
580     case MVT::i8:                                                              \
581       return Enum##_1;                                                         \
582     case MVT::i16:                                                             \
583       return Enum##_2;                                                         \
584     case MVT::i32:                                                             \
585       return Enum##_4;                                                         \
586     case MVT::i64:                                                             \
587       return Enum##_8;                                                         \
588     case MVT::i128:                                                            \
589       return Enum##_16;                                                        \
590     }
591 
592   switch (Opc) {
593     OP_TO_LIBCALL(ISD::ATOMIC_SWAP, SYNC_LOCK_TEST_AND_SET)
594     OP_TO_LIBCALL(ISD::ATOMIC_CMP_SWAP, SYNC_VAL_COMPARE_AND_SWAP)
595     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_ADD, SYNC_FETCH_AND_ADD)
596     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_SUB, SYNC_FETCH_AND_SUB)
597     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_AND, SYNC_FETCH_AND_AND)
598     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_OR, SYNC_FETCH_AND_OR)
599     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_XOR, SYNC_FETCH_AND_XOR)
600     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_NAND, SYNC_FETCH_AND_NAND)
601     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_MAX, SYNC_FETCH_AND_MAX)
602     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_UMAX, SYNC_FETCH_AND_UMAX)
603     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_MIN, SYNC_FETCH_AND_MIN)
604     OP_TO_LIBCALL(ISD::ATOMIC_LOAD_UMIN, SYNC_FETCH_AND_UMIN)
605   }
606 
607 #undef OP_TO_LIBCALL
608 
609   return UNKNOWN_LIBCALL;
610 }
611 
612 RTLIB::Libcall RTLIB::getMEMCPY_ELEMENT_UNORDERED_ATOMIC(uint64_t ElementSize) {
613   switch (ElementSize) {
614   case 1:
615     return MEMCPY_ELEMENT_UNORDERED_ATOMIC_1;
616   case 2:
617     return MEMCPY_ELEMENT_UNORDERED_ATOMIC_2;
618   case 4:
619     return MEMCPY_ELEMENT_UNORDERED_ATOMIC_4;
620   case 8:
621     return MEMCPY_ELEMENT_UNORDERED_ATOMIC_8;
622   case 16:
623     return MEMCPY_ELEMENT_UNORDERED_ATOMIC_16;
624   default:
625     return UNKNOWN_LIBCALL;
626   }
627 }
628 
629 RTLIB::Libcall RTLIB::getMEMMOVE_ELEMENT_UNORDERED_ATOMIC(uint64_t ElementSize) {
630   switch (ElementSize) {
631   case 1:
632     return MEMMOVE_ELEMENT_UNORDERED_ATOMIC_1;
633   case 2:
634     return MEMMOVE_ELEMENT_UNORDERED_ATOMIC_2;
635   case 4:
636     return MEMMOVE_ELEMENT_UNORDERED_ATOMIC_4;
637   case 8:
638     return MEMMOVE_ELEMENT_UNORDERED_ATOMIC_8;
639   case 16:
640     return MEMMOVE_ELEMENT_UNORDERED_ATOMIC_16;
641   default:
642     return UNKNOWN_LIBCALL;
643   }
644 }
645 
646 RTLIB::Libcall RTLIB::getMEMSET_ELEMENT_UNORDERED_ATOMIC(uint64_t ElementSize) {
647   switch (ElementSize) {
648   case 1:
649     return MEMSET_ELEMENT_UNORDERED_ATOMIC_1;
650   case 2:
651     return MEMSET_ELEMENT_UNORDERED_ATOMIC_2;
652   case 4:
653     return MEMSET_ELEMENT_UNORDERED_ATOMIC_4;
654   case 8:
655     return MEMSET_ELEMENT_UNORDERED_ATOMIC_8;
656   case 16:
657     return MEMSET_ELEMENT_UNORDERED_ATOMIC_16;
658   default:
659     return UNKNOWN_LIBCALL;
660   }
661 }
662 
663 /// InitCmpLibcallCCs - Set default comparison libcall CC.
664 static void InitCmpLibcallCCs(ISD::CondCode *CCs) {
665   memset(CCs, ISD::SETCC_INVALID, sizeof(ISD::CondCode)*RTLIB::UNKNOWN_LIBCALL);
666   CCs[RTLIB::OEQ_F32] = ISD::SETEQ;
667   CCs[RTLIB::OEQ_F64] = ISD::SETEQ;
668   CCs[RTLIB::OEQ_F128] = ISD::SETEQ;
669   CCs[RTLIB::OEQ_PPCF128] = ISD::SETEQ;
670   CCs[RTLIB::UNE_F32] = ISD::SETNE;
671   CCs[RTLIB::UNE_F64] = ISD::SETNE;
672   CCs[RTLIB::UNE_F128] = ISD::SETNE;
673   CCs[RTLIB::UNE_PPCF128] = ISD::SETNE;
674   CCs[RTLIB::OGE_F32] = ISD::SETGE;
675   CCs[RTLIB::OGE_F64] = ISD::SETGE;
676   CCs[RTLIB::OGE_F128] = ISD::SETGE;
677   CCs[RTLIB::OGE_PPCF128] = ISD::SETGE;
678   CCs[RTLIB::OLT_F32] = ISD::SETLT;
679   CCs[RTLIB::OLT_F64] = ISD::SETLT;
680   CCs[RTLIB::OLT_F128] = ISD::SETLT;
681   CCs[RTLIB::OLT_PPCF128] = ISD::SETLT;
682   CCs[RTLIB::OLE_F32] = ISD::SETLE;
683   CCs[RTLIB::OLE_F64] = ISD::SETLE;
684   CCs[RTLIB::OLE_F128] = ISD::SETLE;
685   CCs[RTLIB::OLE_PPCF128] = ISD::SETLE;
686   CCs[RTLIB::OGT_F32] = ISD::SETGT;
687   CCs[RTLIB::OGT_F64] = ISD::SETGT;
688   CCs[RTLIB::OGT_F128] = ISD::SETGT;
689   CCs[RTLIB::OGT_PPCF128] = ISD::SETGT;
690   CCs[RTLIB::UO_F32] = ISD::SETNE;
691   CCs[RTLIB::UO_F64] = ISD::SETNE;
692   CCs[RTLIB::UO_F128] = ISD::SETNE;
693   CCs[RTLIB::UO_PPCF128] = ISD::SETNE;
694 }
695 
696 /// NOTE: The TargetMachine owns TLOF.
697 TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm) : TM(tm) {
698   initActions();
699 
700   // Perform these initializations only once.
701   MaxStoresPerMemset = MaxStoresPerMemcpy = MaxStoresPerMemmove =
702       MaxLoadsPerMemcmp = 8;
703   MaxGluedStoresPerMemcpy = 0;
704   MaxStoresPerMemsetOptSize = MaxStoresPerMemcpyOptSize =
705       MaxStoresPerMemmoveOptSize = MaxLoadsPerMemcmpOptSize = 4;
706   HasMultipleConditionRegisters = false;
707   HasExtractBitsInsn = false;
708   JumpIsExpensive = JumpIsExpensiveOverride;
709   PredictableSelectIsExpensive = false;
710   EnableExtLdPromotion = false;
711   StackPointerRegisterToSaveRestore = 0;
712   BooleanContents = UndefinedBooleanContent;
713   BooleanFloatContents = UndefinedBooleanContent;
714   BooleanVectorContents = UndefinedBooleanContent;
715   SchedPreferenceInfo = Sched::ILP;
716   GatherAllAliasesMaxDepth = 18;
717   IsStrictFPEnabled = DisableStrictNodeMutation;
718   // TODO: the default will be switched to 0 in the next commit, along
719   // with the Target-specific changes necessary.
720   MaxAtomicSizeInBitsSupported = 1024;
721 
722   MinCmpXchgSizeInBits = 0;
723   SupportsUnalignedAtomics = false;
724 
725   std::fill(std::begin(LibcallRoutineNames), std::end(LibcallRoutineNames), nullptr);
726 
727   InitLibcalls(TM.getTargetTriple());
728   InitCmpLibcallCCs(CmpLibcallCCs);
729 }
730 
731 void TargetLoweringBase::initActions() {
732   // All operations default to being supported.
733   memset(OpActions, 0, sizeof(OpActions));
734   memset(LoadExtActions, 0, sizeof(LoadExtActions));
735   memset(TruncStoreActions, 0, sizeof(TruncStoreActions));
736   memset(IndexedModeActions, 0, sizeof(IndexedModeActions));
737   memset(CondCodeActions, 0, sizeof(CondCodeActions));
738   std::fill(std::begin(RegClassForVT), std::end(RegClassForVT), nullptr);
739   std::fill(std::begin(TargetDAGCombineArray),
740             std::end(TargetDAGCombineArray), 0);
741 
742   for (MVT VT : MVT::fp_valuetypes()) {
743     MVT IntVT = MVT::getIntegerVT(VT.getFixedSizeInBits());
744     if (IntVT.isValid()) {
745       setOperationAction(ISD::ATOMIC_SWAP, VT, Promote);
746       AddPromotedToType(ISD::ATOMIC_SWAP, VT, IntVT);
747     }
748   }
749 
750   // Set default actions for various operations.
751   for (MVT VT : MVT::all_valuetypes()) {
752     // Default all indexed load / store to expand.
753     for (unsigned IM = (unsigned)ISD::PRE_INC;
754          IM != (unsigned)ISD::LAST_INDEXED_MODE; ++IM) {
755       setIndexedLoadAction(IM, VT, Expand);
756       setIndexedStoreAction(IM, VT, Expand);
757       setIndexedMaskedLoadAction(IM, VT, Expand);
758       setIndexedMaskedStoreAction(IM, VT, Expand);
759     }
760 
761     // Most backends expect to see the node which just returns the value loaded.
762     setOperationAction(ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS, VT, Expand);
763 
764     // These operations default to expand.
765     setOperationAction(ISD::FGETSIGN, VT, Expand);
766     setOperationAction(ISD::CONCAT_VECTORS, VT, Expand);
767     setOperationAction(ISD::FMINNUM, VT, Expand);
768     setOperationAction(ISD::FMAXNUM, VT, Expand);
769     setOperationAction(ISD::FMINNUM_IEEE, VT, Expand);
770     setOperationAction(ISD::FMAXNUM_IEEE, VT, Expand);
771     setOperationAction(ISD::FMINIMUM, VT, Expand);
772     setOperationAction(ISD::FMAXIMUM, VT, Expand);
773     setOperationAction(ISD::FMAD, VT, Expand);
774     setOperationAction(ISD::SMIN, VT, Expand);
775     setOperationAction(ISD::SMAX, VT, Expand);
776     setOperationAction(ISD::UMIN, VT, Expand);
777     setOperationAction(ISD::UMAX, VT, Expand);
778     setOperationAction(ISD::ABS, VT, Expand);
779     setOperationAction(ISD::FSHL, VT, Expand);
780     setOperationAction(ISD::FSHR, VT, Expand);
781     setOperationAction(ISD::SADDSAT, VT, Expand);
782     setOperationAction(ISD::UADDSAT, VT, Expand);
783     setOperationAction(ISD::SSUBSAT, VT, Expand);
784     setOperationAction(ISD::USUBSAT, VT, Expand);
785     setOperationAction(ISD::SSHLSAT, VT, Expand);
786     setOperationAction(ISD::USHLSAT, VT, Expand);
787     setOperationAction(ISD::SMULFIX, VT, Expand);
788     setOperationAction(ISD::SMULFIXSAT, VT, Expand);
789     setOperationAction(ISD::UMULFIX, VT, Expand);
790     setOperationAction(ISD::UMULFIXSAT, VT, Expand);
791     setOperationAction(ISD::SDIVFIX, VT, Expand);
792     setOperationAction(ISD::SDIVFIXSAT, VT, Expand);
793     setOperationAction(ISD::UDIVFIX, VT, Expand);
794     setOperationAction(ISD::UDIVFIXSAT, VT, Expand);
795     setOperationAction(ISD::FP_TO_SINT_SAT, VT, Expand);
796     setOperationAction(ISD::FP_TO_UINT_SAT, VT, Expand);
797 
798     // Overflow operations default to expand
799     setOperationAction(ISD::SADDO, VT, Expand);
800     setOperationAction(ISD::SSUBO, VT, Expand);
801     setOperationAction(ISD::UADDO, VT, Expand);
802     setOperationAction(ISD::USUBO, VT, Expand);
803     setOperationAction(ISD::SMULO, VT, Expand);
804     setOperationAction(ISD::UMULO, VT, Expand);
805 
806     // ADDCARRY operations default to expand
807     setOperationAction(ISD::ADDCARRY, VT, Expand);
808     setOperationAction(ISD::SUBCARRY, VT, Expand);
809     setOperationAction(ISD::SETCCCARRY, VT, Expand);
810     setOperationAction(ISD::SADDO_CARRY, VT, Expand);
811     setOperationAction(ISD::SSUBO_CARRY, VT, Expand);
812 
813     // ADDC/ADDE/SUBC/SUBE default to expand.
814     setOperationAction(ISD::ADDC, VT, Expand);
815     setOperationAction(ISD::ADDE, VT, Expand);
816     setOperationAction(ISD::SUBC, VT, Expand);
817     setOperationAction(ISD::SUBE, VT, Expand);
818 
819     // Absolute difference
820     setOperationAction(ISD::ABDS, VT, Expand);
821     setOperationAction(ISD::ABDU, VT, Expand);
822 
823     // These default to Expand so they will be expanded to CTLZ/CTTZ by default.
824     setOperationAction(ISD::CTLZ_ZERO_UNDEF, VT, Expand);
825     setOperationAction(ISD::CTTZ_ZERO_UNDEF, VT, Expand);
826 
827     setOperationAction(ISD::BITREVERSE, VT, Expand);
828     setOperationAction(ISD::PARITY, VT, Expand);
829 
830     // These library functions default to expand.
831     setOperationAction(ISD::FROUND, VT, Expand);
832     setOperationAction(ISD::FROUNDEVEN, VT, Expand);
833     setOperationAction(ISD::FPOWI, VT, Expand);
834 
835     // These operations default to expand for vector types.
836     if (VT.isVector()) {
837       setOperationAction(ISD::FCOPYSIGN, VT, Expand);
838       setOperationAction(ISD::SIGN_EXTEND_INREG, VT, Expand);
839       setOperationAction(ISD::ANY_EXTEND_VECTOR_INREG, VT, Expand);
840       setOperationAction(ISD::SIGN_EXTEND_VECTOR_INREG, VT, Expand);
841       setOperationAction(ISD::ZERO_EXTEND_VECTOR_INREG, VT, Expand);
842       setOperationAction(ISD::SPLAT_VECTOR, VT, Expand);
843     }
844 
845     // Constrained floating-point operations default to expand.
846 #define DAG_INSTRUCTION(NAME, NARG, ROUND_MODE, INTRINSIC, DAGN)               \
847     setOperationAction(ISD::STRICT_##DAGN, VT, Expand);
848 #include "llvm/IR/ConstrainedOps.def"
849 
850     // For most targets @llvm.get.dynamic.area.offset just returns 0.
851     setOperationAction(ISD::GET_DYNAMIC_AREA_OFFSET, VT, Expand);
852 
853     // Vector reduction default to expand.
854     setOperationAction(ISD::VECREDUCE_FADD, VT, Expand);
855     setOperationAction(ISD::VECREDUCE_FMUL, VT, Expand);
856     setOperationAction(ISD::VECREDUCE_ADD, VT, Expand);
857     setOperationAction(ISD::VECREDUCE_MUL, VT, Expand);
858     setOperationAction(ISD::VECREDUCE_AND, VT, Expand);
859     setOperationAction(ISD::VECREDUCE_OR, VT, Expand);
860     setOperationAction(ISD::VECREDUCE_XOR, VT, Expand);
861     setOperationAction(ISD::VECREDUCE_SMAX, VT, Expand);
862     setOperationAction(ISD::VECREDUCE_SMIN, VT, Expand);
863     setOperationAction(ISD::VECREDUCE_UMAX, VT, Expand);
864     setOperationAction(ISD::VECREDUCE_UMIN, VT, Expand);
865     setOperationAction(ISD::VECREDUCE_FMAX, VT, Expand);
866     setOperationAction(ISD::VECREDUCE_FMIN, VT, Expand);
867     setOperationAction(ISD::VECREDUCE_SEQ_FADD, VT, Expand);
868     setOperationAction(ISD::VECREDUCE_SEQ_FMUL, VT, Expand);
869 
870     // Named vector shuffles default to expand.
871     setOperationAction(ISD::VECTOR_SPLICE, VT, Expand);
872   }
873 
874   // Most targets ignore the @llvm.prefetch intrinsic.
875   setOperationAction(ISD::PREFETCH, MVT::Other, Expand);
876 
877   // Most targets also ignore the @llvm.readcyclecounter intrinsic.
878   setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Expand);
879 
880   // ConstantFP nodes default to expand.  Targets can either change this to
881   // Legal, in which case all fp constants are legal, or use isFPImmLegal()
882   // to optimize expansions for certain constants.
883   setOperationAction(ISD::ConstantFP, MVT::f16, Expand);
884   setOperationAction(ISD::ConstantFP, MVT::f32, Expand);
885   setOperationAction(ISD::ConstantFP, MVT::f64, Expand);
886   setOperationAction(ISD::ConstantFP, MVT::f80, Expand);
887   setOperationAction(ISD::ConstantFP, MVT::f128, Expand);
888 
889   // These library functions default to expand.
890   for (MVT VT : {MVT::f32, MVT::f64, MVT::f128}) {
891     setOperationAction(ISD::FCBRT,      VT, Expand);
892     setOperationAction(ISD::FLOG ,      VT, Expand);
893     setOperationAction(ISD::FLOG2,      VT, Expand);
894     setOperationAction(ISD::FLOG10,     VT, Expand);
895     setOperationAction(ISD::FEXP ,      VT, Expand);
896     setOperationAction(ISD::FEXP2,      VT, Expand);
897     setOperationAction(ISD::FFLOOR,     VT, Expand);
898     setOperationAction(ISD::FNEARBYINT, VT, Expand);
899     setOperationAction(ISD::FCEIL,      VT, Expand);
900     setOperationAction(ISD::FRINT,      VT, Expand);
901     setOperationAction(ISD::FTRUNC,     VT, Expand);
902     setOperationAction(ISD::FROUND,     VT, Expand);
903     setOperationAction(ISD::FROUNDEVEN, VT, Expand);
904     setOperationAction(ISD::LROUND,     VT, Expand);
905     setOperationAction(ISD::LLROUND,    VT, Expand);
906     setOperationAction(ISD::LRINT,      VT, Expand);
907     setOperationAction(ISD::LLRINT,     VT, Expand);
908   }
909 
910   // Default ISD::TRAP to expand (which turns it into abort).
911   setOperationAction(ISD::TRAP, MVT::Other, Expand);
912 
913   // On most systems, DEBUGTRAP and TRAP have no difference. The "Expand"
914   // here is to inform DAG Legalizer to replace DEBUGTRAP with TRAP.
915   setOperationAction(ISD::DEBUGTRAP, MVT::Other, Expand);
916 
917   setOperationAction(ISD::UBSANTRAP, MVT::Other, Expand);
918 }
919 
920 MVT TargetLoweringBase::getScalarShiftAmountTy(const DataLayout &DL,
921                                                EVT) const {
922   return MVT::getIntegerVT(DL.getPointerSizeInBits(0));
923 }
924 
925 EVT TargetLoweringBase::getShiftAmountTy(EVT LHSTy, const DataLayout &DL,
926                                          bool LegalTypes) const {
927   assert(LHSTy.isInteger() && "Shift amount is not an integer type!");
928   if (LHSTy.isVector())
929     return LHSTy;
930   return LegalTypes ? getScalarShiftAmountTy(DL, LHSTy)
931                     : getPointerTy(DL);
932 }
933 
934 bool TargetLoweringBase::canOpTrap(unsigned Op, EVT VT) const {
935   assert(isTypeLegal(VT));
936   switch (Op) {
937   default:
938     return false;
939   case ISD::SDIV:
940   case ISD::UDIV:
941   case ISD::SREM:
942   case ISD::UREM:
943     return true;
944   }
945 }
946 
947 bool TargetLoweringBase::isFreeAddrSpaceCast(unsigned SrcAS,
948                                              unsigned DestAS) const {
949   return TM.isNoopAddrSpaceCast(SrcAS, DestAS);
950 }
951 
952 void TargetLoweringBase::setJumpIsExpensive(bool isExpensive) {
953   // If the command-line option was specified, ignore this request.
954   if (!JumpIsExpensiveOverride.getNumOccurrences())
955     JumpIsExpensive = isExpensive;
956 }
957 
958 TargetLoweringBase::LegalizeKind
959 TargetLoweringBase::getTypeConversion(LLVMContext &Context, EVT VT) const {
960   // If this is a simple type, use the ComputeRegisterProp mechanism.
961   if (VT.isSimple()) {
962     MVT SVT = VT.getSimpleVT();
963     assert((unsigned)SVT.SimpleTy < array_lengthof(TransformToType));
964     MVT NVT = TransformToType[SVT.SimpleTy];
965     LegalizeTypeAction LA = ValueTypeActions.getTypeAction(SVT);
966 
967     assert((LA == TypeLegal || LA == TypeSoftenFloat ||
968             LA == TypeSoftPromoteHalf ||
969             (NVT.isVector() ||
970              ValueTypeActions.getTypeAction(NVT) != TypePromoteInteger)) &&
971            "Promote may not follow Expand or Promote");
972 
973     if (LA == TypeSplitVector)
974       return LegalizeKind(LA, EVT(SVT).getHalfNumVectorElementsVT(Context));
975     if (LA == TypeScalarizeVector)
976       return LegalizeKind(LA, SVT.getVectorElementType());
977     return LegalizeKind(LA, NVT);
978   }
979 
980   // Handle Extended Scalar Types.
981   if (!VT.isVector()) {
982     assert(VT.isInteger() && "Float types must be simple");
983     unsigned BitSize = VT.getSizeInBits();
984     // First promote to a power-of-two size, then expand if necessary.
985     if (BitSize < 8 || !isPowerOf2_32(BitSize)) {
986       EVT NVT = VT.getRoundIntegerType(Context);
987       assert(NVT != VT && "Unable to round integer VT");
988       LegalizeKind NextStep = getTypeConversion(Context, NVT);
989       // Avoid multi-step promotion.
990       if (NextStep.first == TypePromoteInteger)
991         return NextStep;
992       // Return rounded integer type.
993       return LegalizeKind(TypePromoteInteger, NVT);
994     }
995 
996     return LegalizeKind(TypeExpandInteger,
997                         EVT::getIntegerVT(Context, VT.getSizeInBits() / 2));
998   }
999 
1000   // Handle vector types.
1001   ElementCount NumElts = VT.getVectorElementCount();
1002   EVT EltVT = VT.getVectorElementType();
1003 
1004   // Vectors with only one element are always scalarized.
1005   if (NumElts.isScalar())
1006     return LegalizeKind(TypeScalarizeVector, EltVT);
1007 
1008   // Try to widen vector elements until the element type is a power of two and
1009   // promote it to a legal type later on, for example:
1010   // <3 x i8> -> <4 x i8> -> <4 x i32>
1011   if (EltVT.isInteger()) {
1012     // Vectors with a number of elements that is not a power of two are always
1013     // widened, for example <3 x i8> -> <4 x i8>.
1014     if (!VT.isPow2VectorType()) {
1015       NumElts = NumElts.coefficientNextPowerOf2();
1016       EVT NVT = EVT::getVectorVT(Context, EltVT, NumElts);
1017       return LegalizeKind(TypeWidenVector, NVT);
1018     }
1019 
1020     // Examine the element type.
1021     LegalizeKind LK = getTypeConversion(Context, EltVT);
1022 
1023     // If type is to be expanded, split the vector.
1024     //  <4 x i140> -> <2 x i140>
1025     if (LK.first == TypeExpandInteger) {
1026       if (VT.getVectorElementCount().isScalable())
1027         return LegalizeKind(TypeScalarizeScalableVector, EltVT);
1028       return LegalizeKind(TypeSplitVector,
1029                           VT.getHalfNumVectorElementsVT(Context));
1030     }
1031 
1032     // Promote the integer element types until a legal vector type is found
1033     // or until the element integer type is too big. If a legal type was not
1034     // found, fallback to the usual mechanism of widening/splitting the
1035     // vector.
1036     EVT OldEltVT = EltVT;
1037     while (true) {
1038       // Increase the bitwidth of the element to the next pow-of-two
1039       // (which is greater than 8 bits).
1040       EltVT = EVT::getIntegerVT(Context, 1 + EltVT.getSizeInBits())
1041                   .getRoundIntegerType(Context);
1042 
1043       // Stop trying when getting a non-simple element type.
1044       // Note that vector elements may be greater than legal vector element
1045       // types. Example: X86 XMM registers hold 64bit element on 32bit
1046       // systems.
1047       if (!EltVT.isSimple())
1048         break;
1049 
1050       // Build a new vector type and check if it is legal.
1051       MVT NVT = MVT::getVectorVT(EltVT.getSimpleVT(), NumElts);
1052       // Found a legal promoted vector type.
1053       if (NVT != MVT() && ValueTypeActions.getTypeAction(NVT) == TypeLegal)
1054         return LegalizeKind(TypePromoteInteger,
1055                             EVT::getVectorVT(Context, EltVT, NumElts));
1056     }
1057 
1058     // Reset the type to the unexpanded type if we did not find a legal vector
1059     // type with a promoted vector element type.
1060     EltVT = OldEltVT;
1061   }
1062 
1063   // Try to widen the vector until a legal type is found.
1064   // If there is no wider legal type, split the vector.
1065   while (true) {
1066     // Round up to the next power of 2.
1067     NumElts = NumElts.coefficientNextPowerOf2();
1068 
1069     // If there is no simple vector type with this many elements then there
1070     // cannot be a larger legal vector type.  Note that this assumes that
1071     // there are no skipped intermediate vector types in the simple types.
1072     if (!EltVT.isSimple())
1073       break;
1074     MVT LargerVector = MVT::getVectorVT(EltVT.getSimpleVT(), NumElts);
1075     if (LargerVector == MVT())
1076       break;
1077 
1078     // If this type is legal then widen the vector.
1079     if (ValueTypeActions.getTypeAction(LargerVector) == TypeLegal)
1080       return LegalizeKind(TypeWidenVector, LargerVector);
1081   }
1082 
1083   // Widen odd vectors to next power of two.
1084   if (!VT.isPow2VectorType()) {
1085     EVT NVT = VT.getPow2VectorType(Context);
1086     return LegalizeKind(TypeWidenVector, NVT);
1087   }
1088 
1089   if (VT.getVectorElementCount() == ElementCount::getScalable(1))
1090     return LegalizeKind(TypeScalarizeScalableVector, EltVT);
1091 
1092   // Vectors with illegal element types are expanded.
1093   EVT NVT = EVT::getVectorVT(Context, EltVT,
1094                              VT.getVectorElementCount().divideCoefficientBy(2));
1095   return LegalizeKind(TypeSplitVector, NVT);
1096 }
1097 
1098 static unsigned getVectorTypeBreakdownMVT(MVT VT, MVT &IntermediateVT,
1099                                           unsigned &NumIntermediates,
1100                                           MVT &RegisterVT,
1101                                           TargetLoweringBase *TLI) {
1102   // Figure out the right, legal destination reg to copy into.
1103   ElementCount EC = VT.getVectorElementCount();
1104   MVT EltTy = VT.getVectorElementType();
1105 
1106   unsigned NumVectorRegs = 1;
1107 
1108   // Scalable vectors cannot be scalarized, so splitting or widening is
1109   // required.
1110   if (VT.isScalableVector() && !isPowerOf2_32(EC.getKnownMinValue()))
1111     llvm_unreachable(
1112         "Splitting or widening of non-power-of-2 MVTs is not implemented.");
1113 
1114   // FIXME: We don't support non-power-of-2-sized vectors for now.
1115   // Ideally we could break down into LHS/RHS like LegalizeDAG does.
1116   if (!isPowerOf2_32(EC.getKnownMinValue())) {
1117     // Split EC to unit size (scalable property is preserved).
1118     NumVectorRegs = EC.getKnownMinValue();
1119     EC = ElementCount::getFixed(1);
1120   }
1121 
1122   // Divide the input until we get to a supported size. This will
1123   // always end up with an EC that represent a scalar or a scalable
1124   // scalar.
1125   while (EC.getKnownMinValue() > 1 &&
1126          !TLI->isTypeLegal(MVT::getVectorVT(EltTy, EC))) {
1127     EC = EC.divideCoefficientBy(2);
1128     NumVectorRegs <<= 1;
1129   }
1130 
1131   NumIntermediates = NumVectorRegs;
1132 
1133   MVT NewVT = MVT::getVectorVT(EltTy, EC);
1134   if (!TLI->isTypeLegal(NewVT))
1135     NewVT = EltTy;
1136   IntermediateVT = NewVT;
1137 
1138   unsigned LaneSizeInBits = NewVT.getScalarSizeInBits();
1139 
1140   // Convert sizes such as i33 to i64.
1141   if (!isPowerOf2_32(LaneSizeInBits))
1142     LaneSizeInBits = NextPowerOf2(LaneSizeInBits);
1143 
1144   MVT DestVT = TLI->getRegisterType(NewVT);
1145   RegisterVT = DestVT;
1146   if (EVT(DestVT).bitsLT(NewVT))    // Value is expanded, e.g. i64 -> i16.
1147     return NumVectorRegs * (LaneSizeInBits / DestVT.getScalarSizeInBits());
1148 
1149   // Otherwise, promotion or legal types use the same number of registers as
1150   // the vector decimated to the appropriate level.
1151   return NumVectorRegs;
1152 }
1153 
1154 /// isLegalRC - Return true if the value types that can be represented by the
1155 /// specified register class are all legal.
1156 bool TargetLoweringBase::isLegalRC(const TargetRegisterInfo &TRI,
1157                                    const TargetRegisterClass &RC) const {
1158   for (auto I = TRI.legalclasstypes_begin(RC); *I != MVT::Other; ++I)
1159     if (isTypeLegal(*I))
1160       return true;
1161   return false;
1162 }
1163 
1164 /// Replace/modify any TargetFrameIndex operands with a targte-dependent
1165 /// sequence of memory operands that is recognized by PrologEpilogInserter.
1166 MachineBasicBlock *
1167 TargetLoweringBase::emitPatchPoint(MachineInstr &InitialMI,
1168                                    MachineBasicBlock *MBB) const {
1169   MachineInstr *MI = &InitialMI;
1170   MachineFunction &MF = *MI->getMF();
1171   MachineFrameInfo &MFI = MF.getFrameInfo();
1172 
1173   // We're handling multiple types of operands here:
1174   // PATCHPOINT MetaArgs - live-in, read only, direct
1175   // STATEPOINT Deopt Spill - live-through, read only, indirect
1176   // STATEPOINT Deopt Alloca - live-through, read only, direct
1177   // (We're currently conservative and mark the deopt slots read/write in
1178   // practice.)
1179   // STATEPOINT GC Spill - live-through, read/write, indirect
1180   // STATEPOINT GC Alloca - live-through, read/write, direct
1181   // The live-in vs live-through is handled already (the live through ones are
1182   // all stack slots), but we need to handle the different type of stackmap
1183   // operands and memory effects here.
1184 
1185   if (!llvm::any_of(MI->operands(),
1186                     [](MachineOperand &Operand) { return Operand.isFI(); }))
1187     return MBB;
1188 
1189   MachineInstrBuilder MIB = BuildMI(MF, MI->getDebugLoc(), MI->getDesc());
1190 
1191   // Inherit previous memory operands.
1192   MIB.cloneMemRefs(*MI);
1193 
1194   for (unsigned i = 0; i < MI->getNumOperands(); ++i) {
1195     MachineOperand &MO = MI->getOperand(i);
1196     if (!MO.isFI()) {
1197       // Index of Def operand this Use it tied to.
1198       // Since Defs are coming before Uses, if Use is tied, then
1199       // index of Def must be smaller that index of that Use.
1200       // Also, Defs preserve their position in new MI.
1201       unsigned TiedTo = i;
1202       if (MO.isReg() && MO.isTied())
1203         TiedTo = MI->findTiedOperandIdx(i);
1204       MIB.add(MO);
1205       if (TiedTo < i)
1206         MIB->tieOperands(TiedTo, MIB->getNumOperands() - 1);
1207       continue;
1208     }
1209 
1210     // foldMemoryOperand builds a new MI after replacing a single FI operand
1211     // with the canonical set of five x86 addressing-mode operands.
1212     int FI = MO.getIndex();
1213 
1214     // Add frame index operands recognized by stackmaps.cpp
1215     if (MFI.isStatepointSpillSlotObjectIndex(FI)) {
1216       // indirect-mem-ref tag, size, #FI, offset.
1217       // Used for spills inserted by StatepointLowering.  This codepath is not
1218       // used for patchpoints/stackmaps at all, for these spilling is done via
1219       // foldMemoryOperand callback only.
1220       assert(MI->getOpcode() == TargetOpcode::STATEPOINT && "sanity");
1221       MIB.addImm(StackMaps::IndirectMemRefOp);
1222       MIB.addImm(MFI.getObjectSize(FI));
1223       MIB.add(MO);
1224       MIB.addImm(0);
1225     } else {
1226       // direct-mem-ref tag, #FI, offset.
1227       // Used by patchpoint, and direct alloca arguments to statepoints
1228       MIB.addImm(StackMaps::DirectMemRefOp);
1229       MIB.add(MO);
1230       MIB.addImm(0);
1231     }
1232 
1233     assert(MIB->mayLoad() && "Folded a stackmap use to a non-load!");
1234 
1235     // Add a new memory operand for this FI.
1236     assert(MFI.getObjectOffset(FI) != -1);
1237 
1238     // Note: STATEPOINT MMOs are added during SelectionDAG.  STACKMAP, and
1239     // PATCHPOINT should be updated to do the same. (TODO)
1240     if (MI->getOpcode() != TargetOpcode::STATEPOINT) {
1241       auto Flags = MachineMemOperand::MOLoad;
1242       MachineMemOperand *MMO = MF.getMachineMemOperand(
1243           MachinePointerInfo::getFixedStack(MF, FI), Flags,
1244           MF.getDataLayout().getPointerSize(), MFI.getObjectAlign(FI));
1245       MIB->addMemOperand(MF, MMO);
1246     }
1247   }
1248   MBB->insert(MachineBasicBlock::iterator(MI), MIB);
1249   MI->eraseFromParent();
1250   return MBB;
1251 }
1252 
1253 /// findRepresentativeClass - Return the largest legal super-reg register class
1254 /// of the register class for the specified type and its associated "cost".
1255 // This function is in TargetLowering because it uses RegClassForVT which would
1256 // need to be moved to TargetRegisterInfo and would necessitate moving
1257 // isTypeLegal over as well - a massive change that would just require
1258 // TargetLowering having a TargetRegisterInfo class member that it would use.
1259 std::pair<const TargetRegisterClass *, uint8_t>
1260 TargetLoweringBase::findRepresentativeClass(const TargetRegisterInfo *TRI,
1261                                             MVT VT) const {
1262   const TargetRegisterClass *RC = RegClassForVT[VT.SimpleTy];
1263   if (!RC)
1264     return std::make_pair(RC, 0);
1265 
1266   // Compute the set of all super-register classes.
1267   BitVector SuperRegRC(TRI->getNumRegClasses());
1268   for (SuperRegClassIterator RCI(RC, TRI); RCI.isValid(); ++RCI)
1269     SuperRegRC.setBitsInMask(RCI.getMask());
1270 
1271   // Find the first legal register class with the largest spill size.
1272   const TargetRegisterClass *BestRC = RC;
1273   for (unsigned i : SuperRegRC.set_bits()) {
1274     const TargetRegisterClass *SuperRC = TRI->getRegClass(i);
1275     // We want the largest possible spill size.
1276     if (TRI->getSpillSize(*SuperRC) <= TRI->getSpillSize(*BestRC))
1277       continue;
1278     if (!isLegalRC(*TRI, *SuperRC))
1279       continue;
1280     BestRC = SuperRC;
1281   }
1282   return std::make_pair(BestRC, 1);
1283 }
1284 
1285 /// computeRegisterProperties - Once all of the register classes are added,
1286 /// this allows us to compute derived properties we expose.
1287 void TargetLoweringBase::computeRegisterProperties(
1288     const TargetRegisterInfo *TRI) {
1289   static_assert(MVT::VALUETYPE_SIZE <= MVT::MAX_ALLOWED_VALUETYPE,
1290                 "Too many value types for ValueTypeActions to hold!");
1291 
1292   // Everything defaults to needing one register.
1293   for (unsigned i = 0; i != MVT::VALUETYPE_SIZE; ++i) {
1294     NumRegistersForVT[i] = 1;
1295     RegisterTypeForVT[i] = TransformToType[i] = (MVT::SimpleValueType)i;
1296   }
1297   // ...except isVoid, which doesn't need any registers.
1298   NumRegistersForVT[MVT::isVoid] = 0;
1299 
1300   // Find the largest integer register class.
1301   unsigned LargestIntReg = MVT::LAST_INTEGER_VALUETYPE;
1302   for (; RegClassForVT[LargestIntReg] == nullptr; --LargestIntReg)
1303     assert(LargestIntReg != MVT::i1 && "No integer registers defined!");
1304 
1305   // Every integer value type larger than this largest register takes twice as
1306   // many registers to represent as the previous ValueType.
1307   for (unsigned ExpandedReg = LargestIntReg + 1;
1308        ExpandedReg <= MVT::LAST_INTEGER_VALUETYPE; ++ExpandedReg) {
1309     NumRegistersForVT[ExpandedReg] = 2*NumRegistersForVT[ExpandedReg-1];
1310     RegisterTypeForVT[ExpandedReg] = (MVT::SimpleValueType)LargestIntReg;
1311     TransformToType[ExpandedReg] = (MVT::SimpleValueType)(ExpandedReg - 1);
1312     ValueTypeActions.setTypeAction((MVT::SimpleValueType)ExpandedReg,
1313                                    TypeExpandInteger);
1314   }
1315 
1316   // Inspect all of the ValueType's smaller than the largest integer
1317   // register to see which ones need promotion.
1318   unsigned LegalIntReg = LargestIntReg;
1319   for (unsigned IntReg = LargestIntReg - 1;
1320        IntReg >= (unsigned)MVT::i1; --IntReg) {
1321     MVT IVT = (MVT::SimpleValueType)IntReg;
1322     if (isTypeLegal(IVT)) {
1323       LegalIntReg = IntReg;
1324     } else {
1325       RegisterTypeForVT[IntReg] = TransformToType[IntReg] =
1326         (MVT::SimpleValueType)LegalIntReg;
1327       ValueTypeActions.setTypeAction(IVT, TypePromoteInteger);
1328     }
1329   }
1330 
1331   // ppcf128 type is really two f64's.
1332   if (!isTypeLegal(MVT::ppcf128)) {
1333     if (isTypeLegal(MVT::f64)) {
1334       NumRegistersForVT[MVT::ppcf128] = 2*NumRegistersForVT[MVT::f64];
1335       RegisterTypeForVT[MVT::ppcf128] = MVT::f64;
1336       TransformToType[MVT::ppcf128] = MVT::f64;
1337       ValueTypeActions.setTypeAction(MVT::ppcf128, TypeExpandFloat);
1338     } else {
1339       NumRegistersForVT[MVT::ppcf128] = NumRegistersForVT[MVT::i128];
1340       RegisterTypeForVT[MVT::ppcf128] = RegisterTypeForVT[MVT::i128];
1341       TransformToType[MVT::ppcf128] = MVT::i128;
1342       ValueTypeActions.setTypeAction(MVT::ppcf128, TypeSoftenFloat);
1343     }
1344   }
1345 
1346   // Decide how to handle f128. If the target does not have native f128 support,
1347   // expand it to i128 and we will be generating soft float library calls.
1348   if (!isTypeLegal(MVT::f128)) {
1349     NumRegistersForVT[MVT::f128] = NumRegistersForVT[MVT::i128];
1350     RegisterTypeForVT[MVT::f128] = RegisterTypeForVT[MVT::i128];
1351     TransformToType[MVT::f128] = MVT::i128;
1352     ValueTypeActions.setTypeAction(MVT::f128, TypeSoftenFloat);
1353   }
1354 
1355   // Decide how to handle f64. If the target does not have native f64 support,
1356   // expand it to i64 and we will be generating soft float library calls.
1357   if (!isTypeLegal(MVT::f64)) {
1358     NumRegistersForVT[MVT::f64] = NumRegistersForVT[MVT::i64];
1359     RegisterTypeForVT[MVT::f64] = RegisterTypeForVT[MVT::i64];
1360     TransformToType[MVT::f64] = MVT::i64;
1361     ValueTypeActions.setTypeAction(MVT::f64, TypeSoftenFloat);
1362   }
1363 
1364   // Decide how to handle f32. If the target does not have native f32 support,
1365   // expand it to i32 and we will be generating soft float library calls.
1366   if (!isTypeLegal(MVT::f32)) {
1367     NumRegistersForVT[MVT::f32] = NumRegistersForVT[MVT::i32];
1368     RegisterTypeForVT[MVT::f32] = RegisterTypeForVT[MVT::i32];
1369     TransformToType[MVT::f32] = MVT::i32;
1370     ValueTypeActions.setTypeAction(MVT::f32, TypeSoftenFloat);
1371   }
1372 
1373   // Decide how to handle f16. If the target does not have native f16 support,
1374   // promote it to f32, because there are no f16 library calls (except for
1375   // conversions).
1376   if (!isTypeLegal(MVT::f16)) {
1377     // Allow targets to control how we legalize half.
1378     if (softPromoteHalfType()) {
1379       NumRegistersForVT[MVT::f16] = NumRegistersForVT[MVT::i16];
1380       RegisterTypeForVT[MVT::f16] = RegisterTypeForVT[MVT::i16];
1381       TransformToType[MVT::f16] = MVT::f32;
1382       ValueTypeActions.setTypeAction(MVT::f16, TypeSoftPromoteHalf);
1383     } else {
1384       NumRegistersForVT[MVT::f16] = NumRegistersForVT[MVT::f32];
1385       RegisterTypeForVT[MVT::f16] = RegisterTypeForVT[MVT::f32];
1386       TransformToType[MVT::f16] = MVT::f32;
1387       ValueTypeActions.setTypeAction(MVT::f16, TypePromoteFloat);
1388     }
1389   }
1390 
1391   // Loop over all of the vector value types to see which need transformations.
1392   for (unsigned i = MVT::FIRST_VECTOR_VALUETYPE;
1393        i <= (unsigned)MVT::LAST_VECTOR_VALUETYPE; ++i) {
1394     MVT VT = (MVT::SimpleValueType) i;
1395     if (isTypeLegal(VT))
1396       continue;
1397 
1398     MVT EltVT = VT.getVectorElementType();
1399     ElementCount EC = VT.getVectorElementCount();
1400     bool IsLegalWiderType = false;
1401     bool IsScalable = VT.isScalableVector();
1402     LegalizeTypeAction PreferredAction = getPreferredVectorAction(VT);
1403     switch (PreferredAction) {
1404     case TypePromoteInteger: {
1405       MVT::SimpleValueType EndVT = IsScalable ?
1406                                    MVT::LAST_INTEGER_SCALABLE_VECTOR_VALUETYPE :
1407                                    MVT::LAST_INTEGER_FIXEDLEN_VECTOR_VALUETYPE;
1408       // Try to promote the elements of integer vectors. If no legal
1409       // promotion was found, fall through to the widen-vector method.
1410       for (unsigned nVT = i + 1;
1411            (MVT::SimpleValueType)nVT <= EndVT; ++nVT) {
1412         MVT SVT = (MVT::SimpleValueType) nVT;
1413         // Promote vectors of integers to vectors with the same number
1414         // of elements, with a wider element type.
1415         if (SVT.getScalarSizeInBits() > EltVT.getFixedSizeInBits() &&
1416             SVT.getVectorElementCount() == EC && isTypeLegal(SVT)) {
1417           TransformToType[i] = SVT;
1418           RegisterTypeForVT[i] = SVT;
1419           NumRegistersForVT[i] = 1;
1420           ValueTypeActions.setTypeAction(VT, TypePromoteInteger);
1421           IsLegalWiderType = true;
1422           break;
1423         }
1424       }
1425       if (IsLegalWiderType)
1426         break;
1427       LLVM_FALLTHROUGH;
1428     }
1429 
1430     case TypeWidenVector:
1431       if (isPowerOf2_32(EC.getKnownMinValue())) {
1432         // Try to widen the vector.
1433         for (unsigned nVT = i + 1; nVT <= MVT::LAST_VECTOR_VALUETYPE; ++nVT) {
1434           MVT SVT = (MVT::SimpleValueType) nVT;
1435           if (SVT.getVectorElementType() == EltVT &&
1436               SVT.isScalableVector() == IsScalable &&
1437               SVT.getVectorElementCount().getKnownMinValue() >
1438                   EC.getKnownMinValue() &&
1439               isTypeLegal(SVT)) {
1440             TransformToType[i] = SVT;
1441             RegisterTypeForVT[i] = SVT;
1442             NumRegistersForVT[i] = 1;
1443             ValueTypeActions.setTypeAction(VT, TypeWidenVector);
1444             IsLegalWiderType = true;
1445             break;
1446           }
1447         }
1448         if (IsLegalWiderType)
1449           break;
1450       } else {
1451         // Only widen to the next power of 2 to keep consistency with EVT.
1452         MVT NVT = VT.getPow2VectorType();
1453         if (isTypeLegal(NVT)) {
1454           TransformToType[i] = NVT;
1455           ValueTypeActions.setTypeAction(VT, TypeWidenVector);
1456           RegisterTypeForVT[i] = NVT;
1457           NumRegistersForVT[i] = 1;
1458           break;
1459         }
1460       }
1461       LLVM_FALLTHROUGH;
1462 
1463     case TypeSplitVector:
1464     case TypeScalarizeVector: {
1465       MVT IntermediateVT;
1466       MVT RegisterVT;
1467       unsigned NumIntermediates;
1468       unsigned NumRegisters = getVectorTypeBreakdownMVT(VT, IntermediateVT,
1469           NumIntermediates, RegisterVT, this);
1470       NumRegistersForVT[i] = NumRegisters;
1471       assert(NumRegistersForVT[i] == NumRegisters &&
1472              "NumRegistersForVT size cannot represent NumRegisters!");
1473       RegisterTypeForVT[i] = RegisterVT;
1474 
1475       MVT NVT = VT.getPow2VectorType();
1476       if (NVT == VT) {
1477         // Type is already a power of 2.  The default action is to split.
1478         TransformToType[i] = MVT::Other;
1479         if (PreferredAction == TypeScalarizeVector)
1480           ValueTypeActions.setTypeAction(VT, TypeScalarizeVector);
1481         else if (PreferredAction == TypeSplitVector)
1482           ValueTypeActions.setTypeAction(VT, TypeSplitVector);
1483         else if (EC.getKnownMinValue() > 1)
1484           ValueTypeActions.setTypeAction(VT, TypeSplitVector);
1485         else
1486           ValueTypeActions.setTypeAction(VT, EC.isScalable()
1487                                                  ? TypeScalarizeScalableVector
1488                                                  : TypeScalarizeVector);
1489       } else {
1490         TransformToType[i] = NVT;
1491         ValueTypeActions.setTypeAction(VT, TypeWidenVector);
1492       }
1493       break;
1494     }
1495     default:
1496       llvm_unreachable("Unknown vector legalization action!");
1497     }
1498   }
1499 
1500   // Determine the 'representative' register class for each value type.
1501   // An representative register class is the largest (meaning one which is
1502   // not a sub-register class / subreg register class) legal register class for
1503   // a group of value types. For example, on i386, i8, i16, and i32
1504   // representative would be GR32; while on x86_64 it's GR64.
1505   for (unsigned i = 0; i != MVT::VALUETYPE_SIZE; ++i) {
1506     const TargetRegisterClass* RRC;
1507     uint8_t Cost;
1508     std::tie(RRC, Cost) = findRepresentativeClass(TRI, (MVT::SimpleValueType)i);
1509     RepRegClassForVT[i] = RRC;
1510     RepRegClassCostForVT[i] = Cost;
1511   }
1512 }
1513 
1514 EVT TargetLoweringBase::getSetCCResultType(const DataLayout &DL, LLVMContext &,
1515                                            EVT VT) const {
1516   assert(!VT.isVector() && "No default SetCC type for vectors!");
1517   return getPointerTy(DL).SimpleTy;
1518 }
1519 
1520 MVT::SimpleValueType TargetLoweringBase::getCmpLibcallReturnType() const {
1521   return MVT::i32; // return the default value
1522 }
1523 
1524 /// getVectorTypeBreakdown - Vector types are broken down into some number of
1525 /// legal first class types.  For example, MVT::v8f32 maps to 2 MVT::v4f32
1526 /// with Altivec or SSE1, or 8 promoted MVT::f64 values with the X86 FP stack.
1527 /// Similarly, MVT::v2i64 turns into 4 MVT::i32 values with both PPC and X86.
1528 ///
1529 /// This method returns the number of registers needed, and the VT for each
1530 /// register.  It also returns the VT and quantity of the intermediate values
1531 /// before they are promoted/expanded.
1532 unsigned TargetLoweringBase::getVectorTypeBreakdown(LLVMContext &Context,
1533                                                     EVT VT, EVT &IntermediateVT,
1534                                                     unsigned &NumIntermediates,
1535                                                     MVT &RegisterVT) const {
1536   ElementCount EltCnt = VT.getVectorElementCount();
1537 
1538   // If there is a wider vector type with the same element type as this one,
1539   // or a promoted vector type that has the same number of elements which
1540   // are wider, then we should convert to that legal vector type.
1541   // This handles things like <2 x float> -> <4 x float> and
1542   // <4 x i1> -> <4 x i32>.
1543   LegalizeTypeAction TA = getTypeAction(Context, VT);
1544   if (!EltCnt.isScalar() &&
1545       (TA == TypeWidenVector || TA == TypePromoteInteger)) {
1546     EVT RegisterEVT = getTypeToTransformTo(Context, VT);
1547     if (isTypeLegal(RegisterEVT)) {
1548       IntermediateVT = RegisterEVT;
1549       RegisterVT = RegisterEVT.getSimpleVT();
1550       NumIntermediates = 1;
1551       return 1;
1552     }
1553   }
1554 
1555   // Figure out the right, legal destination reg to copy into.
1556   EVT EltTy = VT.getVectorElementType();
1557 
1558   unsigned NumVectorRegs = 1;
1559 
1560   // Scalable vectors cannot be scalarized, so handle the legalisation of the
1561   // types like done elsewhere in SelectionDAG.
1562   if (EltCnt.isScalable()) {
1563     LegalizeKind LK;
1564     EVT PartVT = VT;
1565     do {
1566       // Iterate until we've found a legal (part) type to hold VT.
1567       LK = getTypeConversion(Context, PartVT);
1568       PartVT = LK.second;
1569     } while (LK.first != TypeLegal);
1570 
1571     if (!PartVT.isVector()) {
1572       report_fatal_error(
1573           "Don't know how to legalize this scalable vector type");
1574     }
1575 
1576     NumIntermediates =
1577         divideCeil(VT.getVectorElementCount().getKnownMinValue(),
1578                    PartVT.getVectorElementCount().getKnownMinValue());
1579     IntermediateVT = PartVT;
1580     RegisterVT = getRegisterType(Context, IntermediateVT);
1581     return NumIntermediates;
1582   }
1583 
1584   // FIXME: We don't support non-power-of-2-sized vectors for now.  Ideally
1585   // we could break down into LHS/RHS like LegalizeDAG does.
1586   if (!isPowerOf2_32(EltCnt.getKnownMinValue())) {
1587     NumVectorRegs = EltCnt.getKnownMinValue();
1588     EltCnt = ElementCount::getFixed(1);
1589   }
1590 
1591   // Divide the input until we get to a supported size.  This will always
1592   // end with a scalar if the target doesn't support vectors.
1593   while (EltCnt.getKnownMinValue() > 1 &&
1594          !isTypeLegal(EVT::getVectorVT(Context, EltTy, EltCnt))) {
1595     EltCnt = EltCnt.divideCoefficientBy(2);
1596     NumVectorRegs <<= 1;
1597   }
1598 
1599   NumIntermediates = NumVectorRegs;
1600 
1601   EVT NewVT = EVT::getVectorVT(Context, EltTy, EltCnt);
1602   if (!isTypeLegal(NewVT))
1603     NewVT = EltTy;
1604   IntermediateVT = NewVT;
1605 
1606   MVT DestVT = getRegisterType(Context, NewVT);
1607   RegisterVT = DestVT;
1608 
1609   if (EVT(DestVT).bitsLT(NewVT)) {  // Value is expanded, e.g. i64 -> i16.
1610     TypeSize NewVTSize = NewVT.getSizeInBits();
1611     // Convert sizes such as i33 to i64.
1612     if (!isPowerOf2_32(NewVTSize.getKnownMinSize()))
1613       NewVTSize = NewVTSize.coefficientNextPowerOf2();
1614     return NumVectorRegs*(NewVTSize/DestVT.getSizeInBits());
1615   }
1616 
1617   // Otherwise, promotion or legal types use the same number of registers as
1618   // the vector decimated to the appropriate level.
1619   return NumVectorRegs;
1620 }
1621 
1622 bool TargetLoweringBase::isSuitableForJumpTable(const SwitchInst *SI,
1623                                                 uint64_t NumCases,
1624                                                 uint64_t Range,
1625                                                 ProfileSummaryInfo *PSI,
1626                                                 BlockFrequencyInfo *BFI) const {
1627   // FIXME: This function check the maximum table size and density, but the
1628   // minimum size is not checked. It would be nice if the minimum size is
1629   // also combined within this function. Currently, the minimum size check is
1630   // performed in findJumpTable() in SelectionDAGBuiler and
1631   // getEstimatedNumberOfCaseClusters() in BasicTTIImpl.
1632   const bool OptForSize =
1633       SI->getParent()->getParent()->hasOptSize() ||
1634       llvm::shouldOptimizeForSize(SI->getParent(), PSI, BFI);
1635   const unsigned MinDensity = getMinimumJumpTableDensity(OptForSize);
1636   const unsigned MaxJumpTableSize = getMaximumJumpTableSize();
1637 
1638   // Check whether the number of cases is small enough and
1639   // the range is dense enough for a jump table.
1640   return (OptForSize || Range <= MaxJumpTableSize) &&
1641          (NumCases * 100 >= Range * MinDensity);
1642 }
1643 
1644 /// Get the EVTs and ArgFlags collections that represent the legalized return
1645 /// type of the given function.  This does not require a DAG or a return value,
1646 /// and is suitable for use before any DAGs for the function are constructed.
1647 /// TODO: Move this out of TargetLowering.cpp.
1648 void llvm::GetReturnInfo(CallingConv::ID CC, Type *ReturnType,
1649                          AttributeList attr,
1650                          SmallVectorImpl<ISD::OutputArg> &Outs,
1651                          const TargetLowering &TLI, const DataLayout &DL) {
1652   SmallVector<EVT, 4> ValueVTs;
1653   ComputeValueVTs(TLI, DL, ReturnType, ValueVTs);
1654   unsigned NumValues = ValueVTs.size();
1655   if (NumValues == 0) return;
1656 
1657   for (unsigned j = 0, f = NumValues; j != f; ++j) {
1658     EVT VT = ValueVTs[j];
1659     ISD::NodeType ExtendKind = ISD::ANY_EXTEND;
1660 
1661     if (attr.hasRetAttr(Attribute::SExt))
1662       ExtendKind = ISD::SIGN_EXTEND;
1663     else if (attr.hasRetAttr(Attribute::ZExt))
1664       ExtendKind = ISD::ZERO_EXTEND;
1665 
1666     // FIXME: C calling convention requires the return type to be promoted to
1667     // at least 32-bit. But this is not necessary for non-C calling
1668     // conventions. The frontend should mark functions whose return values
1669     // require promoting with signext or zeroext attributes.
1670     if (ExtendKind != ISD::ANY_EXTEND && VT.isInteger()) {
1671       MVT MinVT = TLI.getRegisterType(ReturnType->getContext(), MVT::i32);
1672       if (VT.bitsLT(MinVT))
1673         VT = MinVT;
1674     }
1675 
1676     unsigned NumParts =
1677         TLI.getNumRegistersForCallingConv(ReturnType->getContext(), CC, VT);
1678     MVT PartVT =
1679         TLI.getRegisterTypeForCallingConv(ReturnType->getContext(), CC, VT);
1680 
1681     // 'inreg' on function refers to return value
1682     ISD::ArgFlagsTy Flags = ISD::ArgFlagsTy();
1683     if (attr.hasRetAttr(Attribute::InReg))
1684       Flags.setInReg();
1685 
1686     // Propagate extension type if any
1687     if (attr.hasRetAttr(Attribute::SExt))
1688       Flags.setSExt();
1689     else if (attr.hasRetAttr(Attribute::ZExt))
1690       Flags.setZExt();
1691 
1692     for (unsigned i = 0; i < NumParts; ++i)
1693       Outs.push_back(ISD::OutputArg(Flags, PartVT, VT, /*isfixed=*/true, 0, 0));
1694   }
1695 }
1696 
1697 /// getByValTypeAlignment - Return the desired alignment for ByVal aggregate
1698 /// function arguments in the caller parameter area.  This is the actual
1699 /// alignment, not its logarithm.
1700 unsigned TargetLoweringBase::getByValTypeAlignment(Type *Ty,
1701                                                    const DataLayout &DL) const {
1702   return DL.getABITypeAlign(Ty).value();
1703 }
1704 
1705 bool TargetLoweringBase::allowsMemoryAccessForAlignment(
1706     LLVMContext &Context, const DataLayout &DL, EVT VT, unsigned AddrSpace,
1707     Align Alignment, MachineMemOperand::Flags Flags, bool *Fast) const {
1708   // Check if the specified alignment is sufficient based on the data layout.
1709   // TODO: While using the data layout works in practice, a better solution
1710   // would be to implement this check directly (make this a virtual function).
1711   // For example, the ABI alignment may change based on software platform while
1712   // this function should only be affected by hardware implementation.
1713   Type *Ty = VT.getTypeForEVT(Context);
1714   if (VT.isZeroSized() || Alignment >= DL.getABITypeAlign(Ty)) {
1715     // Assume that an access that meets the ABI-specified alignment is fast.
1716     if (Fast != nullptr)
1717       *Fast = true;
1718     return true;
1719   }
1720 
1721   // This is a misaligned access.
1722   return allowsMisalignedMemoryAccesses(VT, AddrSpace, Alignment, Flags, Fast);
1723 }
1724 
1725 bool TargetLoweringBase::allowsMemoryAccessForAlignment(
1726     LLVMContext &Context, const DataLayout &DL, EVT VT,
1727     const MachineMemOperand &MMO, bool *Fast) const {
1728   return allowsMemoryAccessForAlignment(Context, DL, VT, MMO.getAddrSpace(),
1729                                         MMO.getAlign(), MMO.getFlags(), Fast);
1730 }
1731 
1732 bool TargetLoweringBase::allowsMemoryAccess(LLVMContext &Context,
1733                                             const DataLayout &DL, EVT VT,
1734                                             unsigned AddrSpace, Align Alignment,
1735                                             MachineMemOperand::Flags Flags,
1736                                             bool *Fast) const {
1737   return allowsMemoryAccessForAlignment(Context, DL, VT, AddrSpace, Alignment,
1738                                         Flags, Fast);
1739 }
1740 
1741 bool TargetLoweringBase::allowsMemoryAccess(LLVMContext &Context,
1742                                             const DataLayout &DL, EVT VT,
1743                                             const MachineMemOperand &MMO,
1744                                             bool *Fast) const {
1745   return allowsMemoryAccess(Context, DL, VT, MMO.getAddrSpace(), MMO.getAlign(),
1746                             MMO.getFlags(), Fast);
1747 }
1748 
1749 bool TargetLoweringBase::allowsMemoryAccess(LLVMContext &Context,
1750                                             const DataLayout &DL, LLT Ty,
1751                                             const MachineMemOperand &MMO,
1752                                             bool *Fast) const {
1753   EVT VT = getApproximateEVTForLLT(Ty, DL, Context);
1754   return allowsMemoryAccess(Context, DL, VT, MMO.getAddrSpace(), MMO.getAlign(),
1755                             MMO.getFlags(), Fast);
1756 }
1757 
1758 //===----------------------------------------------------------------------===//
1759 //  TargetTransformInfo Helpers
1760 //===----------------------------------------------------------------------===//
1761 
1762 int TargetLoweringBase::InstructionOpcodeToISD(unsigned Opcode) const {
1763   enum InstructionOpcodes {
1764 #define HANDLE_INST(NUM, OPCODE, CLASS) OPCODE = NUM,
1765 #define LAST_OTHER_INST(NUM) InstructionOpcodesCount = NUM
1766 #include "llvm/IR/Instruction.def"
1767   };
1768   switch (static_cast<InstructionOpcodes>(Opcode)) {
1769   case Ret:            return 0;
1770   case Br:             return 0;
1771   case Switch:         return 0;
1772   case IndirectBr:     return 0;
1773   case Invoke:         return 0;
1774   case CallBr:         return 0;
1775   case Resume:         return 0;
1776   case Unreachable:    return 0;
1777   case CleanupRet:     return 0;
1778   case CatchRet:       return 0;
1779   case CatchPad:       return 0;
1780   case CatchSwitch:    return 0;
1781   case CleanupPad:     return 0;
1782   case FNeg:           return ISD::FNEG;
1783   case Add:            return ISD::ADD;
1784   case FAdd:           return ISD::FADD;
1785   case Sub:            return ISD::SUB;
1786   case FSub:           return ISD::FSUB;
1787   case Mul:            return ISD::MUL;
1788   case FMul:           return ISD::FMUL;
1789   case UDiv:           return ISD::UDIV;
1790   case SDiv:           return ISD::SDIV;
1791   case FDiv:           return ISD::FDIV;
1792   case URem:           return ISD::UREM;
1793   case SRem:           return ISD::SREM;
1794   case FRem:           return ISD::FREM;
1795   case Shl:            return ISD::SHL;
1796   case LShr:           return ISD::SRL;
1797   case AShr:           return ISD::SRA;
1798   case And:            return ISD::AND;
1799   case Or:             return ISD::OR;
1800   case Xor:            return ISD::XOR;
1801   case Alloca:         return 0;
1802   case Load:           return ISD::LOAD;
1803   case Store:          return ISD::STORE;
1804   case GetElementPtr:  return 0;
1805   case Fence:          return 0;
1806   case AtomicCmpXchg:  return 0;
1807   case AtomicRMW:      return 0;
1808   case Trunc:          return ISD::TRUNCATE;
1809   case ZExt:           return ISD::ZERO_EXTEND;
1810   case SExt:           return ISD::SIGN_EXTEND;
1811   case FPToUI:         return ISD::FP_TO_UINT;
1812   case FPToSI:         return ISD::FP_TO_SINT;
1813   case UIToFP:         return ISD::UINT_TO_FP;
1814   case SIToFP:         return ISD::SINT_TO_FP;
1815   case FPTrunc:        return ISD::FP_ROUND;
1816   case FPExt:          return ISD::FP_EXTEND;
1817   case PtrToInt:       return ISD::BITCAST;
1818   case IntToPtr:       return ISD::BITCAST;
1819   case BitCast:        return ISD::BITCAST;
1820   case AddrSpaceCast:  return ISD::ADDRSPACECAST;
1821   case ICmp:           return ISD::SETCC;
1822   case FCmp:           return ISD::SETCC;
1823   case PHI:            return 0;
1824   case Call:           return 0;
1825   case Select:         return ISD::SELECT;
1826   case UserOp1:        return 0;
1827   case UserOp2:        return 0;
1828   case VAArg:          return 0;
1829   case ExtractElement: return ISD::EXTRACT_VECTOR_ELT;
1830   case InsertElement:  return ISD::INSERT_VECTOR_ELT;
1831   case ShuffleVector:  return ISD::VECTOR_SHUFFLE;
1832   case ExtractValue:   return ISD::MERGE_VALUES;
1833   case InsertValue:    return ISD::MERGE_VALUES;
1834   case LandingPad:     return 0;
1835   case Freeze:         return ISD::FREEZE;
1836   }
1837 
1838   llvm_unreachable("Unknown instruction type encountered!");
1839 }
1840 
1841 std::pair<InstructionCost, MVT>
1842 TargetLoweringBase::getTypeLegalizationCost(const DataLayout &DL,
1843                                             Type *Ty) const {
1844   LLVMContext &C = Ty->getContext();
1845   EVT MTy = getValueType(DL, Ty);
1846 
1847   InstructionCost Cost = 1;
1848   // We keep legalizing the type until we find a legal kind. We assume that
1849   // the only operation that costs anything is the split. After splitting
1850   // we need to handle two types.
1851   while (true) {
1852     LegalizeKind LK = getTypeConversion(C, MTy);
1853 
1854     if (LK.first == TypeScalarizeScalableVector)
1855       return std::make_pair(InstructionCost::getInvalid(), MVT::getVT(Ty));
1856 
1857     if (LK.first == TypeLegal)
1858       return std::make_pair(Cost, MTy.getSimpleVT());
1859 
1860     if (LK.first == TypeSplitVector || LK.first == TypeExpandInteger)
1861       Cost *= 2;
1862 
1863     // Do not loop with f128 type.
1864     if (MTy == LK.second)
1865       return std::make_pair(Cost, MTy.getSimpleVT());
1866 
1867     // Keep legalizing the type.
1868     MTy = LK.second;
1869   }
1870 }
1871 
1872 Value *
1873 TargetLoweringBase::getDefaultSafeStackPointerLocation(IRBuilderBase &IRB,
1874                                                        bool UseTLS) const {
1875   // compiler-rt provides a variable with a magic name.  Targets that do not
1876   // link with compiler-rt may also provide such a variable.
1877   Module *M = IRB.GetInsertBlock()->getParent()->getParent();
1878   const char *UnsafeStackPtrVar = "__safestack_unsafe_stack_ptr";
1879   auto UnsafeStackPtr =
1880       dyn_cast_or_null<GlobalVariable>(M->getNamedValue(UnsafeStackPtrVar));
1881 
1882   Type *StackPtrTy = Type::getInt8PtrTy(M->getContext());
1883 
1884   if (!UnsafeStackPtr) {
1885     auto TLSModel = UseTLS ?
1886         GlobalValue::InitialExecTLSModel :
1887         GlobalValue::NotThreadLocal;
1888     // The global variable is not defined yet, define it ourselves.
1889     // We use the initial-exec TLS model because we do not support the
1890     // variable living anywhere other than in the main executable.
1891     UnsafeStackPtr = new GlobalVariable(
1892         *M, StackPtrTy, false, GlobalValue::ExternalLinkage, nullptr,
1893         UnsafeStackPtrVar, nullptr, TLSModel);
1894   } else {
1895     // The variable exists, check its type and attributes.
1896     if (UnsafeStackPtr->getValueType() != StackPtrTy)
1897       report_fatal_error(Twine(UnsafeStackPtrVar) + " must have void* type");
1898     if (UseTLS != UnsafeStackPtr->isThreadLocal())
1899       report_fatal_error(Twine(UnsafeStackPtrVar) + " must " +
1900                          (UseTLS ? "" : "not ") + "be thread-local");
1901   }
1902   return UnsafeStackPtr;
1903 }
1904 
1905 Value *
1906 TargetLoweringBase::getSafeStackPointerLocation(IRBuilderBase &IRB) const {
1907   if (!TM.getTargetTriple().isAndroid())
1908     return getDefaultSafeStackPointerLocation(IRB, true);
1909 
1910   // Android provides a libc function to retrieve the address of the current
1911   // thread's unsafe stack pointer.
1912   Module *M = IRB.GetInsertBlock()->getParent()->getParent();
1913   Type *StackPtrTy = Type::getInt8PtrTy(M->getContext());
1914   FunctionCallee Fn = M->getOrInsertFunction("__safestack_pointer_address",
1915                                              StackPtrTy->getPointerTo(0));
1916   return IRB.CreateCall(Fn);
1917 }
1918 
1919 //===----------------------------------------------------------------------===//
1920 //  Loop Strength Reduction hooks
1921 //===----------------------------------------------------------------------===//
1922 
1923 /// isLegalAddressingMode - Return true if the addressing mode represented
1924 /// by AM is legal for this target, for a load/store of the specified type.
1925 bool TargetLoweringBase::isLegalAddressingMode(const DataLayout &DL,
1926                                                const AddrMode &AM, Type *Ty,
1927                                                unsigned AS, Instruction *I) const {
1928   // The default implementation of this implements a conservative RISCy, r+r and
1929   // r+i addr mode.
1930 
1931   // Allows a sign-extended 16-bit immediate field.
1932   if (AM.BaseOffs <= -(1LL << 16) || AM.BaseOffs >= (1LL << 16)-1)
1933     return false;
1934 
1935   // No global is ever allowed as a base.
1936   if (AM.BaseGV)
1937     return false;
1938 
1939   // Only support r+r,
1940   switch (AM.Scale) {
1941   case 0:  // "r+i" or just "i", depending on HasBaseReg.
1942     break;
1943   case 1:
1944     if (AM.HasBaseReg && AM.BaseOffs)  // "r+r+i" is not allowed.
1945       return false;
1946     // Otherwise we have r+r or r+i.
1947     break;
1948   case 2:
1949     if (AM.HasBaseReg || AM.BaseOffs)  // 2*r+r  or  2*r+i is not allowed.
1950       return false;
1951     // Allow 2*r as r+r.
1952     break;
1953   default: // Don't allow n * r
1954     return false;
1955   }
1956 
1957   return true;
1958 }
1959 
1960 //===----------------------------------------------------------------------===//
1961 //  Stack Protector
1962 //===----------------------------------------------------------------------===//
1963 
1964 // For OpenBSD return its special guard variable. Otherwise return nullptr,
1965 // so that SelectionDAG handle SSP.
1966 Value *TargetLoweringBase::getIRStackGuard(IRBuilderBase &IRB) const {
1967   if (getTargetMachine().getTargetTriple().isOSOpenBSD()) {
1968     Module &M = *IRB.GetInsertBlock()->getParent()->getParent();
1969     PointerType *PtrTy = Type::getInt8PtrTy(M.getContext());
1970     Constant *C = M.getOrInsertGlobal("__guard_local", PtrTy);
1971     if (GlobalVariable *G = dyn_cast_or_null<GlobalVariable>(C))
1972       G->setVisibility(GlobalValue::HiddenVisibility);
1973     return C;
1974   }
1975   return nullptr;
1976 }
1977 
1978 // Currently only support "standard" __stack_chk_guard.
1979 // TODO: add LOAD_STACK_GUARD support.
1980 void TargetLoweringBase::insertSSPDeclarations(Module &M) const {
1981   if (!M.getNamedValue("__stack_chk_guard")) {
1982     auto *GV = new GlobalVariable(M, Type::getInt8PtrTy(M.getContext()), false,
1983                                   GlobalVariable::ExternalLinkage, nullptr,
1984                                   "__stack_chk_guard");
1985     if (TM.getRelocationModel() == Reloc::Static &&
1986         !TM.getTargetTriple().isWindowsGNUEnvironment())
1987       GV->setDSOLocal(true);
1988   }
1989 }
1990 
1991 // Currently only support "standard" __stack_chk_guard.
1992 // TODO: add LOAD_STACK_GUARD support.
1993 Value *TargetLoweringBase::getSDagStackGuard(const Module &M) const {
1994   return M.getNamedValue("__stack_chk_guard");
1995 }
1996 
1997 Function *TargetLoweringBase::getSSPStackGuardCheck(const Module &M) const {
1998   return nullptr;
1999 }
2000 
2001 unsigned TargetLoweringBase::getMinimumJumpTableEntries() const {
2002   return MinimumJumpTableEntries;
2003 }
2004 
2005 void TargetLoweringBase::setMinimumJumpTableEntries(unsigned Val) {
2006   MinimumJumpTableEntries = Val;
2007 }
2008 
2009 unsigned TargetLoweringBase::getMinimumJumpTableDensity(bool OptForSize) const {
2010   return OptForSize ? OptsizeJumpTableDensity : JumpTableDensity;
2011 }
2012 
2013 unsigned TargetLoweringBase::getMaximumJumpTableSize() const {
2014   return MaximumJumpTableSize;
2015 }
2016 
2017 void TargetLoweringBase::setMaximumJumpTableSize(unsigned Val) {
2018   MaximumJumpTableSize = Val;
2019 }
2020 
2021 bool TargetLoweringBase::isJumpTableRelative() const {
2022   return getTargetMachine().isPositionIndependent();
2023 }
2024 
2025 Align TargetLoweringBase::getPrefLoopAlignment(MachineLoop *ML) const {
2026   if (TM.Options.LoopAlignment)
2027     return Align(TM.Options.LoopAlignment);
2028   return PrefLoopAlignment;
2029 }
2030 
2031 //===----------------------------------------------------------------------===//
2032 //  Reciprocal Estimates
2033 //===----------------------------------------------------------------------===//
2034 
2035 /// Get the reciprocal estimate attribute string for a function that will
2036 /// override the target defaults.
2037 static StringRef getRecipEstimateForFunc(MachineFunction &MF) {
2038   const Function &F = MF.getFunction();
2039   return F.getFnAttribute("reciprocal-estimates").getValueAsString();
2040 }
2041 
2042 /// Construct a string for the given reciprocal operation of the given type.
2043 /// This string should match the corresponding option to the front-end's
2044 /// "-mrecip" flag assuming those strings have been passed through in an
2045 /// attribute string. For example, "vec-divf" for a division of a vXf32.
2046 static std::string getReciprocalOpName(bool IsSqrt, EVT VT) {
2047   std::string Name = VT.isVector() ? "vec-" : "";
2048 
2049   Name += IsSqrt ? "sqrt" : "div";
2050 
2051   // TODO: Handle "half" or other float types?
2052   if (VT.getScalarType() == MVT::f64) {
2053     Name += "d";
2054   } else {
2055     assert(VT.getScalarType() == MVT::f32 &&
2056            "Unexpected FP type for reciprocal estimate");
2057     Name += "f";
2058   }
2059 
2060   return Name;
2061 }
2062 
2063 /// Return the character position and value (a single numeric character) of a
2064 /// customized refinement operation in the input string if it exists. Return
2065 /// false if there is no customized refinement step count.
2066 static bool parseRefinementStep(StringRef In, size_t &Position,
2067                                 uint8_t &Value) {
2068   const char RefStepToken = ':';
2069   Position = In.find(RefStepToken);
2070   if (Position == StringRef::npos)
2071     return false;
2072 
2073   StringRef RefStepString = In.substr(Position + 1);
2074   // Allow exactly one numeric character for the additional refinement
2075   // step parameter.
2076   if (RefStepString.size() == 1) {
2077     char RefStepChar = RefStepString[0];
2078     if (isDigit(RefStepChar)) {
2079       Value = RefStepChar - '0';
2080       return true;
2081     }
2082   }
2083   report_fatal_error("Invalid refinement step for -recip.");
2084 }
2085 
2086 /// For the input attribute string, return one of the ReciprocalEstimate enum
2087 /// status values (enabled, disabled, or not specified) for this operation on
2088 /// the specified data type.
2089 static int getOpEnabled(bool IsSqrt, EVT VT, StringRef Override) {
2090   if (Override.empty())
2091     return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2092 
2093   SmallVector<StringRef, 4> OverrideVector;
2094   Override.split(OverrideVector, ',');
2095   unsigned NumArgs = OverrideVector.size();
2096 
2097   // Check if "all", "none", or "default" was specified.
2098   if (NumArgs == 1) {
2099     // Look for an optional setting of the number of refinement steps needed
2100     // for this type of reciprocal operation.
2101     size_t RefPos;
2102     uint8_t RefSteps;
2103     if (parseRefinementStep(Override, RefPos, RefSteps)) {
2104       // Split the string for further processing.
2105       Override = Override.substr(0, RefPos);
2106     }
2107 
2108     // All reciprocal types are enabled.
2109     if (Override == "all")
2110       return TargetLoweringBase::ReciprocalEstimate::Enabled;
2111 
2112     // All reciprocal types are disabled.
2113     if (Override == "none")
2114       return TargetLoweringBase::ReciprocalEstimate::Disabled;
2115 
2116     // Target defaults for enablement are used.
2117     if (Override == "default")
2118       return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2119   }
2120 
2121   // The attribute string may omit the size suffix ('f'/'d').
2122   std::string VTName = getReciprocalOpName(IsSqrt, VT);
2123   std::string VTNameNoSize = VTName;
2124   VTNameNoSize.pop_back();
2125   static const char DisabledPrefix = '!';
2126 
2127   for (StringRef RecipType : OverrideVector) {
2128     size_t RefPos;
2129     uint8_t RefSteps;
2130     if (parseRefinementStep(RecipType, RefPos, RefSteps))
2131       RecipType = RecipType.substr(0, RefPos);
2132 
2133     // Ignore the disablement token for string matching.
2134     bool IsDisabled = RecipType[0] == DisabledPrefix;
2135     if (IsDisabled)
2136       RecipType = RecipType.substr(1);
2137 
2138     if (RecipType.equals(VTName) || RecipType.equals(VTNameNoSize))
2139       return IsDisabled ? TargetLoweringBase::ReciprocalEstimate::Disabled
2140                         : TargetLoweringBase::ReciprocalEstimate::Enabled;
2141   }
2142 
2143   return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2144 }
2145 
2146 /// For the input attribute string, return the customized refinement step count
2147 /// for this operation on the specified data type. If the step count does not
2148 /// exist, return the ReciprocalEstimate enum value for unspecified.
2149 static int getOpRefinementSteps(bool IsSqrt, EVT VT, StringRef Override) {
2150   if (Override.empty())
2151     return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2152 
2153   SmallVector<StringRef, 4> OverrideVector;
2154   Override.split(OverrideVector, ',');
2155   unsigned NumArgs = OverrideVector.size();
2156 
2157   // Check if "all", "default", or "none" was specified.
2158   if (NumArgs == 1) {
2159     // Look for an optional setting of the number of refinement steps needed
2160     // for this type of reciprocal operation.
2161     size_t RefPos;
2162     uint8_t RefSteps;
2163     if (!parseRefinementStep(Override, RefPos, RefSteps))
2164       return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2165 
2166     // Split the string for further processing.
2167     Override = Override.substr(0, RefPos);
2168     assert(Override != "none" &&
2169            "Disabled reciprocals, but specifed refinement steps?");
2170 
2171     // If this is a general override, return the specified number of steps.
2172     if (Override == "all" || Override == "default")
2173       return RefSteps;
2174   }
2175 
2176   // The attribute string may omit the size suffix ('f'/'d').
2177   std::string VTName = getReciprocalOpName(IsSqrt, VT);
2178   std::string VTNameNoSize = VTName;
2179   VTNameNoSize.pop_back();
2180 
2181   for (StringRef RecipType : OverrideVector) {
2182     size_t RefPos;
2183     uint8_t RefSteps;
2184     if (!parseRefinementStep(RecipType, RefPos, RefSteps))
2185       continue;
2186 
2187     RecipType = RecipType.substr(0, RefPos);
2188     if (RecipType.equals(VTName) || RecipType.equals(VTNameNoSize))
2189       return RefSteps;
2190   }
2191 
2192   return TargetLoweringBase::ReciprocalEstimate::Unspecified;
2193 }
2194 
2195 int TargetLoweringBase::getRecipEstimateSqrtEnabled(EVT VT,
2196                                                     MachineFunction &MF) const {
2197   return getOpEnabled(true, VT, getRecipEstimateForFunc(MF));
2198 }
2199 
2200 int TargetLoweringBase::getRecipEstimateDivEnabled(EVT VT,
2201                                                    MachineFunction &MF) const {
2202   return getOpEnabled(false, VT, getRecipEstimateForFunc(MF));
2203 }
2204 
2205 int TargetLoweringBase::getSqrtRefinementSteps(EVT VT,
2206                                                MachineFunction &MF) const {
2207   return getOpRefinementSteps(true, VT, getRecipEstimateForFunc(MF));
2208 }
2209 
2210 int TargetLoweringBase::getDivRefinementSteps(EVT VT,
2211                                               MachineFunction &MF) const {
2212   return getOpRefinementSteps(false, VT, getRecipEstimateForFunc(MF));
2213 }
2214 
2215 void TargetLoweringBase::finalizeLowering(MachineFunction &MF) const {
2216   MF.getRegInfo().freezeReservedRegs(MF);
2217 }
2218 
2219 MachineMemOperand::Flags
2220 TargetLoweringBase::getLoadMemOperandFlags(const LoadInst &LI,
2221                                            const DataLayout &DL) const {
2222   MachineMemOperand::Flags Flags = MachineMemOperand::MOLoad;
2223   if (LI.isVolatile())
2224     Flags |= MachineMemOperand::MOVolatile;
2225 
2226   if (LI.hasMetadata(LLVMContext::MD_nontemporal))
2227     Flags |= MachineMemOperand::MONonTemporal;
2228 
2229   if (LI.hasMetadata(LLVMContext::MD_invariant_load))
2230     Flags |= MachineMemOperand::MOInvariant;
2231 
2232   if (isDereferenceablePointer(LI.getPointerOperand(), LI.getType(), DL))
2233     Flags |= MachineMemOperand::MODereferenceable;
2234 
2235   Flags |= getTargetMMOFlags(LI);
2236   return Flags;
2237 }
2238 
2239 MachineMemOperand::Flags
2240 TargetLoweringBase::getStoreMemOperandFlags(const StoreInst &SI,
2241                                             const DataLayout &DL) const {
2242   MachineMemOperand::Flags Flags = MachineMemOperand::MOStore;
2243 
2244   if (SI.isVolatile())
2245     Flags |= MachineMemOperand::MOVolatile;
2246 
2247   if (SI.hasMetadata(LLVMContext::MD_nontemporal))
2248     Flags |= MachineMemOperand::MONonTemporal;
2249 
2250   // FIXME: Not preserving dereferenceable
2251   Flags |= getTargetMMOFlags(SI);
2252   return Flags;
2253 }
2254 
2255 MachineMemOperand::Flags
2256 TargetLoweringBase::getAtomicMemOperandFlags(const Instruction &AI,
2257                                              const DataLayout &DL) const {
2258   auto Flags = MachineMemOperand::MOLoad | MachineMemOperand::MOStore;
2259 
2260   if (const AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(&AI)) {
2261     if (RMW->isVolatile())
2262       Flags |= MachineMemOperand::MOVolatile;
2263   } else if (const AtomicCmpXchgInst *CmpX = dyn_cast<AtomicCmpXchgInst>(&AI)) {
2264     if (CmpX->isVolatile())
2265       Flags |= MachineMemOperand::MOVolatile;
2266   } else
2267     llvm_unreachable("not an atomic instruction");
2268 
2269   // FIXME: Not preserving dereferenceable
2270   Flags |= getTargetMMOFlags(AI);
2271   return Flags;
2272 }
2273 
2274 Instruction *TargetLoweringBase::emitLeadingFence(IRBuilderBase &Builder,
2275                                                   Instruction *Inst,
2276                                                   AtomicOrdering Ord) const {
2277   if (isReleaseOrStronger(Ord) && Inst->hasAtomicStore())
2278     return Builder.CreateFence(Ord);
2279   else
2280     return nullptr;
2281 }
2282 
2283 Instruction *TargetLoweringBase::emitTrailingFence(IRBuilderBase &Builder,
2284                                                    Instruction *Inst,
2285                                                    AtomicOrdering Ord) const {
2286   if (isAcquireOrStronger(Ord))
2287     return Builder.CreateFence(Ord);
2288   else
2289     return nullptr;
2290 }
2291 
2292 //===----------------------------------------------------------------------===//
2293 //  GlobalISel Hooks
2294 //===----------------------------------------------------------------------===//
2295 
2296 bool TargetLoweringBase::shouldLocalize(const MachineInstr &MI,
2297                                         const TargetTransformInfo *TTI) const {
2298   auto &MF = *MI.getMF();
2299   auto &MRI = MF.getRegInfo();
2300   // Assuming a spill and reload of a value has a cost of 1 instruction each,
2301   // this helper function computes the maximum number of uses we should consider
2302   // for remat. E.g. on arm64 global addresses take 2 insts to materialize. We
2303   // break even in terms of code size when the original MI has 2 users vs
2304   // choosing to potentially spill. Any more than 2 users we we have a net code
2305   // size increase. This doesn't take into account register pressure though.
2306   auto maxUses = [](unsigned RematCost) {
2307     // A cost of 1 means remats are basically free.
2308     if (RematCost == 1)
2309       return UINT_MAX;
2310     if (RematCost == 2)
2311       return 2U;
2312 
2313     // Remat is too expensive, only sink if there's one user.
2314     if (RematCost > 2)
2315       return 1U;
2316     llvm_unreachable("Unexpected remat cost");
2317   };
2318 
2319   // Helper to walk through uses and terminate if we've reached a limit. Saves
2320   // us spending time traversing uses if all we want to know is if it's >= min.
2321   auto isUsesAtMost = [&](unsigned Reg, unsigned MaxUses) {
2322     unsigned NumUses = 0;
2323     auto UI = MRI.use_instr_nodbg_begin(Reg), UE = MRI.use_instr_nodbg_end();
2324     for (; UI != UE && NumUses < MaxUses; ++UI) {
2325       NumUses++;
2326     }
2327     // If we haven't reached the end yet then there are more than MaxUses users.
2328     return UI == UE;
2329   };
2330 
2331   switch (MI.getOpcode()) {
2332   default:
2333     return false;
2334   // Constants-like instructions should be close to their users.
2335   // We don't want long live-ranges for them.
2336   case TargetOpcode::G_CONSTANT:
2337   case TargetOpcode::G_FCONSTANT:
2338   case TargetOpcode::G_FRAME_INDEX:
2339   case TargetOpcode::G_INTTOPTR:
2340     return true;
2341   case TargetOpcode::G_GLOBAL_VALUE: {
2342     unsigned RematCost = TTI->getGISelRematGlobalCost();
2343     Register Reg = MI.getOperand(0).getReg();
2344     unsigned MaxUses = maxUses(RematCost);
2345     if (MaxUses == UINT_MAX)
2346       return true; // Remats are "free" so always localize.
2347     bool B = isUsesAtMost(Reg, MaxUses);
2348     return B;
2349   }
2350   }
2351 }
2352