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1 //===-- AMDGPUTargetMachine.cpp - TargetMachine for hw codegen targets-----===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 /// \file
11 /// \brief The AMDGPU target machine contains all of the hardware specific
12 /// information  needed to emit code for R600 and SI GPUs.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "AMDGPUTargetMachine.h"
17 #include "AMDGPU.h"
18 #include "AMDGPUCallLowering.h"
19 #include "AMDGPUTargetObjectFile.h"
20 #include "AMDGPUTargetTransformInfo.h"
21 #include "R600ISelLowering.h"
22 #include "R600InstrInfo.h"
23 #include "R600MachineScheduler.h"
24 #include "SIISelLowering.h"
25 #include "SIInstrInfo.h"
26 
27 #include "llvm/Analysis/Passes.h"
28 #include "llvm/CodeGen/GlobalISel/IRTranslator.h"
29 #include "llvm/CodeGen/MachineFunctionAnalysis.h"
30 #include "llvm/CodeGen/MachineModuleInfo.h"
31 #include "llvm/CodeGen/Passes.h"
32 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
33 #include "llvm/CodeGen/TargetPassConfig.h"
34 #include "llvm/IR/Verifier.h"
35 #include "llvm/MC/MCAsmInfo.h"
36 #include "llvm/IR/LegacyPassManager.h"
37 #include "llvm/Support/TargetRegistry.h"
38 #include "llvm/Support/raw_os_ostream.h"
39 #include "llvm/Transforms/IPO.h"
40 #include "llvm/Transforms/Scalar.h"
41 #include "llvm/Transforms/Scalar/GVN.h"
42 #include "llvm/Transforms/Vectorize.h"
43 
44 using namespace llvm;
45 
46 static cl::opt<bool> EnableR600StructurizeCFG(
47   "r600-ir-structurize",
48   cl::desc("Use StructurizeCFG IR pass"),
49   cl::init(true));
50 
51 static cl::opt<bool> EnableSROA(
52   "amdgpu-sroa",
53   cl::desc("Run SROA after promote alloca pass"),
54   cl::ReallyHidden,
55   cl::init(true));
56 
57 static cl::opt<bool> EnableR600IfConvert(
58   "r600-if-convert",
59   cl::desc("Use if conversion pass"),
60   cl::ReallyHidden,
61   cl::init(true));
62 
63 // Option to disable vectorizer for tests.
64 static cl::opt<bool> EnableLoadStoreVectorizer(
65   "amdgpu-load-store-vectorizer",
66   cl::desc("Enable load store vectorizer"),
67   cl::init(false),
68   cl::Hidden);
69 
LLVMInitializeAMDGPUTarget()70 extern "C" void LLVMInitializeAMDGPUTarget() {
71   // Register the target
72   RegisterTargetMachine<R600TargetMachine> X(TheAMDGPUTarget);
73   RegisterTargetMachine<GCNTargetMachine> Y(TheGCNTarget);
74 
75   PassRegistry *PR = PassRegistry::getPassRegistry();
76   initializeSILowerI1CopiesPass(*PR);
77   initializeSIFixSGPRCopiesPass(*PR);
78   initializeSIFoldOperandsPass(*PR);
79   initializeSIShrinkInstructionsPass(*PR);
80   initializeSIFixControlFlowLiveIntervalsPass(*PR);
81   initializeSILoadStoreOptimizerPass(*PR);
82   initializeAMDGPUAnnotateKernelFeaturesPass(*PR);
83   initializeAMDGPUAnnotateUniformValuesPass(*PR);
84   initializeAMDGPUPromoteAllocaPass(*PR);
85   initializeAMDGPUCodeGenPreparePass(*PR);
86   initializeSIAnnotateControlFlowPass(*PR);
87   initializeSIDebuggerInsertNopsPass(*PR);
88   initializeSIInsertWaitsPass(*PR);
89   initializeSIWholeQuadModePass(*PR);
90   initializeSILowerControlFlowPass(*PR);
91   initializeSIDebuggerInsertNopsPass(*PR);
92 }
93 
createTLOF(const Triple & TT)94 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
95   return make_unique<AMDGPUTargetObjectFile>();
96 }
97 
createR600MachineScheduler(MachineSchedContext * C)98 static ScheduleDAGInstrs *createR600MachineScheduler(MachineSchedContext *C) {
99   return new ScheduleDAGMILive(C, make_unique<R600SchedStrategy>());
100 }
101 
102 static MachineSchedRegistry
103 R600SchedRegistry("r600", "Run R600's custom scheduler",
104                    createR600MachineScheduler);
105 
106 static MachineSchedRegistry
107 SISchedRegistry("si", "Run SI's custom scheduler",
108                 createSIMachineScheduler);
109 
computeDataLayout(const Triple & TT)110 static StringRef computeDataLayout(const Triple &TT) {
111   if (TT.getArch() == Triple::r600) {
112     // 32-bit pointers.
113     return "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128"
114             "-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64";
115   }
116 
117   // 32-bit private, local, and region pointers. 64-bit global, constant and
118   // flat.
119   return "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32"
120          "-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128"
121          "-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64";
122 }
123 
124 LLVM_READNONE
getGPUOrDefault(const Triple & TT,StringRef GPU)125 static StringRef getGPUOrDefault(const Triple &TT, StringRef GPU) {
126   if (!GPU.empty())
127     return GPU;
128 
129   // HSA only supports CI+, so change the default GPU to a CI for HSA.
130   if (TT.getArch() == Triple::amdgcn)
131     return (TT.getOS() == Triple::AMDHSA) ? "kaveri" : "tahiti";
132 
133   return "r600";
134 }
135 
getEffectiveRelocModel(Optional<Reloc::Model> RM)136 static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
137   // The AMDGPU toolchain only supports generating shared objects, so we
138   // must always use PIC.
139   return Reloc::PIC_;
140 }
141 
AMDGPUTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,TargetOptions Options,Optional<Reloc::Model> RM,CodeModel::Model CM,CodeGenOpt::Level OptLevel)142 AMDGPUTargetMachine::AMDGPUTargetMachine(const Target &T, const Triple &TT,
143                                          StringRef CPU, StringRef FS,
144                                          TargetOptions Options,
145                                          Optional<Reloc::Model> RM,
146                                          CodeModel::Model CM,
147                                          CodeGenOpt::Level OptLevel)
148   : LLVMTargetMachine(T, computeDataLayout(TT), TT, getGPUOrDefault(TT, CPU),
149                       FS, Options, getEffectiveRelocModel(RM), CM, OptLevel),
150     TLOF(createTLOF(getTargetTriple())),
151     IntrinsicInfo() {
152   setRequiresStructuredCFG(true);
153   initAsmInfo();
154 }
155 
~AMDGPUTargetMachine()156 AMDGPUTargetMachine::~AMDGPUTargetMachine() { }
157 
getGPUName(const Function & F) const158 StringRef AMDGPUTargetMachine::getGPUName(const Function &F) const {
159   Attribute GPUAttr = F.getFnAttribute("target-cpu");
160   return GPUAttr.hasAttribute(Attribute::None) ?
161     getTargetCPU() : GPUAttr.getValueAsString();
162 }
163 
getFeatureString(const Function & F) const164 StringRef AMDGPUTargetMachine::getFeatureString(const Function &F) const {
165   Attribute FSAttr = F.getFnAttribute("target-features");
166 
167   return FSAttr.hasAttribute(Attribute::None) ?
168     getTargetFeatureString() :
169     FSAttr.getValueAsString();
170 }
171 
172 //===----------------------------------------------------------------------===//
173 // R600 Target Machine (R600 -> Cayman)
174 //===----------------------------------------------------------------------===//
175 
R600TargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,TargetOptions Options,Optional<Reloc::Model> RM,CodeModel::Model CM,CodeGenOpt::Level OL)176 R600TargetMachine::R600TargetMachine(const Target &T, const Triple &TT,
177                                      StringRef CPU, StringRef FS,
178                                      TargetOptions Options,
179                                      Optional<Reloc::Model> RM,
180                                      CodeModel::Model CM, CodeGenOpt::Level OL)
181   : AMDGPUTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL) {}
182 
getSubtargetImpl(const Function & F) const183 const R600Subtarget *R600TargetMachine::getSubtargetImpl(
184   const Function &F) const {
185   StringRef GPU = getGPUName(F);
186   StringRef FS = getFeatureString(F);
187 
188   SmallString<128> SubtargetKey(GPU);
189   SubtargetKey.append(FS);
190 
191   auto &I = SubtargetMap[SubtargetKey];
192   if (!I) {
193     // This needs to be done before we create a new subtarget since any
194     // creation will depend on the TM and the code generation flags on the
195     // function that reside in TargetOptions.
196     resetTargetOptions(F);
197     I = llvm::make_unique<R600Subtarget>(TargetTriple, GPU, FS, *this);
198   }
199 
200   return I.get();
201 }
202 
203 //===----------------------------------------------------------------------===//
204 // GCN Target Machine (SI+)
205 //===----------------------------------------------------------------------===//
206 
207 #ifdef LLVM_BUILD_GLOBAL_ISEL
208 namespace {
209 struct SIGISelActualAccessor : public GISelAccessor {
210   std::unique_ptr<AMDGPUCallLowering> CallLoweringInfo;
getCallLowering__anonf1666bae0111::SIGISelActualAccessor211   const AMDGPUCallLowering *getCallLowering() const override {
212     return CallLoweringInfo.get();
213   }
214 };
215 } // End anonymous namespace.
216 #endif
217 
GCNTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,TargetOptions Options,Optional<Reloc::Model> RM,CodeModel::Model CM,CodeGenOpt::Level OL)218 GCNTargetMachine::GCNTargetMachine(const Target &T, const Triple &TT,
219                                    StringRef CPU, StringRef FS,
220                                    TargetOptions Options,
221                                    Optional<Reloc::Model> RM,
222                                    CodeModel::Model CM, CodeGenOpt::Level OL)
223   : AMDGPUTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL) {}
224 
getSubtargetImpl(const Function & F) const225 const SISubtarget *GCNTargetMachine::getSubtargetImpl(const Function &F) const {
226   StringRef GPU = getGPUName(F);
227   StringRef FS = getFeatureString(F);
228 
229   SmallString<128> SubtargetKey(GPU);
230   SubtargetKey.append(FS);
231 
232   auto &I = SubtargetMap[SubtargetKey];
233   if (!I) {
234     // This needs to be done before we create a new subtarget since any
235     // creation will depend on the TM and the code generation flags on the
236     // function that reside in TargetOptions.
237     resetTargetOptions(F);
238     I = llvm::make_unique<SISubtarget>(TargetTriple, GPU, FS, *this);
239 
240 #ifndef LLVM_BUILD_GLOBAL_ISEL
241     GISelAccessor *GISel = new GISelAccessor();
242 #else
243     SIGISelActualAccessor *GISel = new SIGISelActualAccessor();
244     GISel->CallLoweringInfo.reset(
245       new AMDGPUCallLowering(*I->getTargetLowering()));
246 #endif
247 
248     I->setGISelAccessor(*GISel);
249   }
250 
251   return I.get();
252 }
253 
254 //===----------------------------------------------------------------------===//
255 // AMDGPU Pass Setup
256 //===----------------------------------------------------------------------===//
257 
258 namespace {
259 
260 class AMDGPUPassConfig : public TargetPassConfig {
261 public:
AMDGPUPassConfig(TargetMachine * TM,PassManagerBase & PM)262   AMDGPUPassConfig(TargetMachine *TM, PassManagerBase &PM)
263     : TargetPassConfig(TM, PM) {
264 
265     // Exceptions and StackMaps are not supported, so these passes will never do
266     // anything.
267     disablePass(&StackMapLivenessID);
268     disablePass(&FuncletLayoutID);
269   }
270 
getAMDGPUTargetMachine() const271   AMDGPUTargetMachine &getAMDGPUTargetMachine() const {
272     return getTM<AMDGPUTargetMachine>();
273   }
274 
275   void addEarlyCSEOrGVNPass();
276   void addStraightLineScalarOptimizationPasses();
277   void addIRPasses() override;
278   void addCodeGenPrepare() override;
279   bool addPreISel() override;
280   bool addInstSelector() override;
281   bool addGCPasses() override;
282 };
283 
284 class R600PassConfig final : public AMDGPUPassConfig {
285 public:
R600PassConfig(TargetMachine * TM,PassManagerBase & PM)286   R600PassConfig(TargetMachine *TM, PassManagerBase &PM)
287     : AMDGPUPassConfig(TM, PM) { }
288 
createMachineScheduler(MachineSchedContext * C) const289   ScheduleDAGInstrs *createMachineScheduler(
290     MachineSchedContext *C) const override {
291     return createR600MachineScheduler(C);
292   }
293 
294   bool addPreISel() override;
295   void addPreRegAlloc() override;
296   void addPreSched2() override;
297   void addPreEmitPass() override;
298 };
299 
300 class GCNPassConfig final : public AMDGPUPassConfig {
301 public:
GCNPassConfig(TargetMachine * TM,PassManagerBase & PM)302   GCNPassConfig(TargetMachine *TM, PassManagerBase &PM)
303     : AMDGPUPassConfig(TM, PM) { }
304 
getGCNTargetMachine() const305   GCNTargetMachine &getGCNTargetMachine() const {
306     return getTM<GCNTargetMachine>();
307   }
308 
309   ScheduleDAGInstrs *
310   createMachineScheduler(MachineSchedContext *C) const override;
311 
312   bool addPreISel() override;
313   void addMachineSSAOptimization() override;
314   bool addInstSelector() override;
315 #ifdef LLVM_BUILD_GLOBAL_ISEL
316   bool addIRTranslator() override;
317   bool addRegBankSelect() override;
318 #endif
319   void addFastRegAlloc(FunctionPass *RegAllocPass) override;
320   void addOptimizedRegAlloc(FunctionPass *RegAllocPass) override;
321   void addPreRegAlloc() override;
322   void addPreSched2() override;
323   void addPreEmitPass() override;
324 };
325 
326 } // End of anonymous namespace
327 
getTargetIRAnalysis()328 TargetIRAnalysis AMDGPUTargetMachine::getTargetIRAnalysis() {
329   return TargetIRAnalysis([this](const Function &F) {
330     return TargetTransformInfo(AMDGPUTTIImpl(this, F));
331   });
332 }
333 
addEarlyCSEOrGVNPass()334 void AMDGPUPassConfig::addEarlyCSEOrGVNPass() {
335   if (getOptLevel() == CodeGenOpt::Aggressive)
336     addPass(createGVNPass());
337   else
338     addPass(createEarlyCSEPass());
339 }
340 
addStraightLineScalarOptimizationPasses()341 void AMDGPUPassConfig::addStraightLineScalarOptimizationPasses() {
342   addPass(createSeparateConstOffsetFromGEPPass());
343   addPass(createSpeculativeExecutionPass());
344   // ReassociateGEPs exposes more opportunites for SLSR. See
345   // the example in reassociate-geps-and-slsr.ll.
346   addPass(createStraightLineStrengthReducePass());
347   // SeparateConstOffsetFromGEP and SLSR creates common expressions which GVN or
348   // EarlyCSE can reuse.
349   addEarlyCSEOrGVNPass();
350   // Run NaryReassociate after EarlyCSE/GVN to be more effective.
351   addPass(createNaryReassociatePass());
352   // NaryReassociate on GEPs creates redundant common expressions, so run
353   // EarlyCSE after it.
354   addPass(createEarlyCSEPass());
355 }
356 
addIRPasses()357 void AMDGPUPassConfig::addIRPasses() {
358   // There is no reason to run these.
359   disablePass(&StackMapLivenessID);
360   disablePass(&FuncletLayoutID);
361   disablePass(&PatchableFunctionID);
362 
363   // Function calls are not supported, so make sure we inline everything.
364   addPass(createAMDGPUAlwaysInlinePass());
365   addPass(createAlwaysInlinerPass());
366   // We need to add the barrier noop pass, otherwise adding the function
367   // inlining pass will cause all of the PassConfigs passes to be run
368   // one function at a time, which means if we have a nodule with two
369   // functions, then we will generate code for the first function
370   // without ever running any passes on the second.
371   addPass(createBarrierNoopPass());
372 
373   // Handle uses of OpenCL image2d_t, image3d_t and sampler_t arguments.
374   addPass(createAMDGPUOpenCLImageTypeLoweringPass());
375 
376   const AMDGPUTargetMachine &TM = getAMDGPUTargetMachine();
377   if (TM.getOptLevel() > CodeGenOpt::None) {
378     addPass(createAMDGPUPromoteAlloca(&TM));
379 
380     if (EnableSROA)
381       addPass(createSROAPass());
382   }
383 
384   addStraightLineScalarOptimizationPasses();
385 
386   TargetPassConfig::addIRPasses();
387 
388   // EarlyCSE is not always strong enough to clean up what LSR produces. For
389   // example, GVN can combine
390   //
391   //   %0 = add %a, %b
392   //   %1 = add %b, %a
393   //
394   // and
395   //
396   //   %0 = shl nsw %a, 2
397   //   %1 = shl %a, 2
398   //
399   // but EarlyCSE can do neither of them.
400   if (getOptLevel() != CodeGenOpt::None)
401     addEarlyCSEOrGVNPass();
402 }
403 
addCodeGenPrepare()404 void AMDGPUPassConfig::addCodeGenPrepare() {
405   TargetPassConfig::addCodeGenPrepare();
406 
407   if (EnableLoadStoreVectorizer)
408     addPass(createLoadStoreVectorizerPass());
409 }
410 
addPreISel()411 bool AMDGPUPassConfig::addPreISel() {
412   addPass(createFlattenCFGPass());
413   return false;
414 }
415 
addInstSelector()416 bool AMDGPUPassConfig::addInstSelector() {
417   addPass(createAMDGPUISelDag(getAMDGPUTargetMachine()));
418   return false;
419 }
420 
addGCPasses()421 bool AMDGPUPassConfig::addGCPasses() {
422   // Do nothing. GC is not supported.
423   return false;
424 }
425 
426 //===----------------------------------------------------------------------===//
427 // R600 Pass Setup
428 //===----------------------------------------------------------------------===//
429 
addPreISel()430 bool R600PassConfig::addPreISel() {
431   AMDGPUPassConfig::addPreISel();
432 
433   if (EnableR600StructurizeCFG)
434     addPass(createStructurizeCFGPass());
435   return false;
436 }
437 
addPreRegAlloc()438 void R600PassConfig::addPreRegAlloc() {
439   addPass(createR600VectorRegMerger(*TM));
440 }
441 
addPreSched2()442 void R600PassConfig::addPreSched2() {
443   addPass(createR600EmitClauseMarkers(), false);
444   if (EnableR600IfConvert)
445     addPass(&IfConverterID, false);
446   addPass(createR600ClauseMergePass(*TM), false);
447 }
448 
addPreEmitPass()449 void R600PassConfig::addPreEmitPass() {
450   addPass(createAMDGPUCFGStructurizerPass(), false);
451   addPass(createR600ExpandSpecialInstrsPass(*TM), false);
452   addPass(&FinalizeMachineBundlesID, false);
453   addPass(createR600Packetizer(*TM), false);
454   addPass(createR600ControlFlowFinalizer(*TM), false);
455 }
456 
createPassConfig(PassManagerBase & PM)457 TargetPassConfig *R600TargetMachine::createPassConfig(PassManagerBase &PM) {
458   return new R600PassConfig(this, PM);
459 }
460 
461 //===----------------------------------------------------------------------===//
462 // GCN Pass Setup
463 //===----------------------------------------------------------------------===//
464 
createMachineScheduler(MachineSchedContext * C) const465 ScheduleDAGInstrs *GCNPassConfig::createMachineScheduler(
466   MachineSchedContext *C) const {
467   const SISubtarget &ST = C->MF->getSubtarget<SISubtarget>();
468   if (ST.enableSIScheduler())
469     return createSIMachineScheduler(C);
470   return nullptr;
471 }
472 
addPreISel()473 bool GCNPassConfig::addPreISel() {
474   AMDGPUPassConfig::addPreISel();
475 
476   // FIXME: We need to run a pass to propagate the attributes when calls are
477   // supported.
478   addPass(&AMDGPUAnnotateKernelFeaturesID);
479   addPass(createStructurizeCFGPass(true)); // true -> SkipUniformRegions
480   addPass(createSinkingPass());
481   addPass(createSITypeRewriter());
482   addPass(createAMDGPUAnnotateUniformValues());
483   addPass(createSIAnnotateControlFlowPass());
484 
485   return false;
486 }
487 
addMachineSSAOptimization()488 void GCNPassConfig::addMachineSSAOptimization() {
489   TargetPassConfig::addMachineSSAOptimization();
490 
491   // We want to fold operands after PeepholeOptimizer has run (or as part of
492   // it), because it will eliminate extra copies making it easier to fold the
493   // real source operand. We want to eliminate dead instructions after, so that
494   // we see fewer uses of the copies. We then need to clean up the dead
495   // instructions leftover after the operands are folded as well.
496   //
497   // XXX - Can we get away without running DeadMachineInstructionElim again?
498   addPass(&SIFoldOperandsID);
499   addPass(&DeadMachineInstructionElimID);
500 }
501 
addInstSelector()502 bool GCNPassConfig::addInstSelector() {
503   AMDGPUPassConfig::addInstSelector();
504   addPass(createSILowerI1CopiesPass());
505   addPass(&SIFixSGPRCopiesID);
506   return false;
507 }
508 
509 #ifdef LLVM_BUILD_GLOBAL_ISEL
addIRTranslator()510 bool GCNPassConfig::addIRTranslator() {
511   addPass(new IRTranslator());
512   return false;
513 }
514 
addRegBankSelect()515 bool GCNPassConfig::addRegBankSelect() {
516   return false;
517 }
518 #endif
519 
addPreRegAlloc()520 void GCNPassConfig::addPreRegAlloc() {
521   // This needs to be run directly before register allocation because
522   // earlier passes might recompute live intervals.
523   // TODO: handle CodeGenOpt::None; fast RA ignores spill weights set by the pass
524   if (getOptLevel() > CodeGenOpt::None) {
525     insertPass(&MachineSchedulerID, &SIFixControlFlowLiveIntervalsID);
526   }
527 
528   if (getOptLevel() > CodeGenOpt::None) {
529     // Don't do this with no optimizations since it throws away debug info by
530     // merging nonadjacent loads.
531 
532     // This should be run after scheduling, but before register allocation. It
533     // also need extra copies to the address operand to be eliminated.
534 
535     // FIXME: Move pre-RA and remove extra reg coalescer run.
536     insertPass(&MachineSchedulerID, &SILoadStoreOptimizerID);
537     insertPass(&MachineSchedulerID, &RegisterCoalescerID);
538   }
539 
540   addPass(createSIShrinkInstructionsPass());
541   addPass(createSIWholeQuadModePass());
542 }
543 
addFastRegAlloc(FunctionPass * RegAllocPass)544 void GCNPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
545   TargetPassConfig::addFastRegAlloc(RegAllocPass);
546 }
547 
addOptimizedRegAlloc(FunctionPass * RegAllocPass)548 void GCNPassConfig::addOptimizedRegAlloc(FunctionPass *RegAllocPass) {
549   TargetPassConfig::addOptimizedRegAlloc(RegAllocPass);
550 }
551 
addPreSched2()552 void GCNPassConfig::addPreSched2() {
553 }
554 
addPreEmitPass()555 void GCNPassConfig::addPreEmitPass() {
556   // The hazard recognizer that runs as part of the post-ra scheduler does not
557   // guarantee to be able handle all hazards correctly. This is because if there
558   // are multiple scheduling regions in a basic block, the regions are scheduled
559   // bottom up, so when we begin to schedule a region we don't know what
560   // instructions were emitted directly before it.
561   //
562   // Here we add a stand-alone hazard recognizer pass which can handle all
563   // cases.
564   addPass(&PostRAHazardRecognizerID);
565 
566   addPass(createSIInsertWaitsPass());
567   addPass(createSIShrinkInstructionsPass());
568   addPass(createSILowerControlFlowPass());
569   addPass(createSIDebuggerInsertNopsPass());
570 }
571 
createPassConfig(PassManagerBase & PM)572 TargetPassConfig *GCNTargetMachine::createPassConfig(PassManagerBase &PM) {
573   return new GCNPassConfig(this, PM);
574 }
575