lib/Target/AArch64/AArch64PreLegalizerCombiner.cpp

   1 //=== lib/CodeGen/GlobalISel/AArch64PreLegalizerCombiner.cpp --------------===//
   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 pass does combining of machine instructions at the generic MI level,
  10 // before the legalizer.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "AArch64TargetMachine.h"
  15 #include "llvm/CodeGen/GlobalISel/Combiner.h"
  16 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
  17 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
  18 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
  19 #include "llvm/CodeGen/MachineFunctionPass.h"
  20 #include "llvm/CodeGen/TargetPassConfig.h"
  21 #include "llvm/Support/Debug.h"
  22
  23 #define DEBUG_TYPE "aarch64-prelegalizer-combiner"
  24
  25 using namespace llvm;
  26 using namespace MIPatternMatch;
  27
  28 namespace {
  29 class AArch64PreLegalizerCombinerInfo : public CombinerInfo {
  30 public:
  31   AArch64PreLegalizerCombinerInfo()
  32       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
  33                      /*LegalizerInfo*/ nullptr) {}
  34   virtual bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
  35                        MachineIRBuilder &B) const override;
  36 };
  37
  38 bool AArch64PreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
  39                                               MachineInstr &MI,
  40                                               MachineIRBuilder &B) const {
  41   CombinerHelper Helper(Observer, B);
  42
  43   switch (MI.getOpcode()) {
  44   default:
  45     return false;
  46   case TargetOpcode::G_LOAD:
  47   case TargetOpcode::G_SEXTLOAD:
  48   case TargetOpcode::G_ZEXTLOAD:
  49     return Helper.tryCombineExtendingLoads(MI);
  50   }
  51
  52   return false;
  53 }
  54
  55 // Pass boilerplate
  56 // ================
  57
  58 class AArch64PreLegalizerCombiner : public MachineFunctionPass {
  59 public:
  60   static char ID;
  61
  62   AArch64PreLegalizerCombiner();
  63
  64   StringRef getPassName() const override { return "AArch64PreLegalizerCombiner"; }
  65
  66   bool runOnMachineFunction(MachineFunction &MF) override;
  67
  68   void getAnalysisUsage(AnalysisUsage &AU) const override;
  69 };
  70 }
  71
  72 void AArch64PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
  73   AU.addRequired<TargetPassConfig>();
  74   AU.setPreservesCFG();
  75   getSelectionDAGFallbackAnalysisUsage(AU);
  76   MachineFunctionPass::getAnalysisUsage(AU);
  77 }
  78
  79 AArch64PreLegalizerCombiner::AArch64PreLegalizerCombiner() : MachineFunctionPass(ID) {
  80   initializeAArch64PreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
  81 }
  82
  83 bool AArch64PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
  84   if (MF.getProperties().hasProperty(
  85           MachineFunctionProperties::Property::FailedISel))
  86     return false;
  87   auto *TPC = &getAnalysis<TargetPassConfig>();
  88   AArch64PreLegalizerCombinerInfo PCInfo;
  89   Combiner C(PCInfo, TPC);
  90   return C.combineMachineInstrs(MF, /*CSEInfo*/ nullptr);
  91 }
  92
  93 char AArch64PreLegalizerCombiner::ID = 0;
  94 INITIALIZE_PASS_BEGIN(AArch64PreLegalizerCombiner, DEBUG_TYPE,
  95                       "Combine AArch64 machine instrs before legalization",
  96                       false, false)
  97 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
  98 INITIALIZE_PASS_END(AArch64PreLegalizerCombiner, DEBUG_TYPE,
  99                     "Combine AArch64 machine instrs before legalization", false,
 100                     false)
 101
 102
 103 namespace llvm {
 104 FunctionPass *createAArch64PreLegalizeCombiner() {
 105   return new AArch64PreLegalizerCombiner();
 106 }
 107 } // end namespace llvm