1 //=== lib/CodeGen/GlobalISel/AArch64O0PreLegalizerCombiner.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 "AArch64GlobalISelUtils.h" 15 #include "AArch64TargetMachine.h" 16 #include "llvm/CodeGen/GlobalISel/Combiner.h" 17 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h" 18 #include "llvm/CodeGen/GlobalISel/CombinerInfo.h" 19 #include "llvm/CodeGen/GlobalISel/GIMatchTableExecutorImpl.h" 20 #include "llvm/CodeGen/GlobalISel/GISelKnownBits.h" 21 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h" 22 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h" 23 #include "llvm/CodeGen/MachineDominators.h" 24 #include "llvm/CodeGen/MachineFunction.h" 25 #include "llvm/CodeGen/MachineFunctionPass.h" 26 #include "llvm/CodeGen/MachineRegisterInfo.h" 27 #include "llvm/CodeGen/TargetPassConfig.h" 28 #include "llvm/IR/Instructions.h" 29 #include "llvm/Support/Debug.h" 30 31 #define GET_GICOMBINER_DEPS 32 #include "AArch64GenO0PreLegalizeGICombiner.inc" 33 #undef GET_GICOMBINER_DEPS 34 35 #define DEBUG_TYPE "aarch64-O0-prelegalizer-combiner" 36 37 using namespace llvm; 38 using namespace MIPatternMatch; 39 namespace { 40 #define GET_GICOMBINER_TYPES 41 #include "AArch64GenO0PreLegalizeGICombiner.inc" 42 #undef GET_GICOMBINER_TYPES 43 44 class AArch64O0PreLegalizerCombinerImpl : public Combiner { 45 protected: 46 // TODO: Make CombinerHelper methods const. 47 mutable CombinerHelper Helper; 48 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig; 49 const AArch64Subtarget &STI; 50 51 public: 52 AArch64O0PreLegalizerCombinerImpl( 53 MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC, 54 GISelKnownBits &KB, GISelCSEInfo *CSEInfo, 55 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig, 56 const AArch64Subtarget &STI); 57 58 static const char *getName() { return "AArch64O0PreLegalizerCombiner"; } 59 60 bool tryCombineAll(MachineInstr &I) const override; 61 62 bool tryCombineAllImpl(MachineInstr &I) const; 63 64 private: 65 #define GET_GICOMBINER_CLASS_MEMBERS 66 #include "AArch64GenO0PreLegalizeGICombiner.inc" 67 #undef GET_GICOMBINER_CLASS_MEMBERS 68 }; 69 70 #define GET_GICOMBINER_IMPL 71 #include "AArch64GenO0PreLegalizeGICombiner.inc" 72 #undef GET_GICOMBINER_IMPL 73 74 AArch64O0PreLegalizerCombinerImpl::AArch64O0PreLegalizerCombinerImpl( 75 MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC, 76 GISelKnownBits &KB, GISelCSEInfo *CSEInfo, 77 const AArch64O0PreLegalizerCombinerImplRuleConfig &RuleConfig, 78 const AArch64Subtarget &STI) 79 : Combiner(MF, CInfo, TPC, &KB, CSEInfo), 80 Helper(Observer, B, /*IsPreLegalize*/ true, &KB), RuleConfig(RuleConfig), 81 STI(STI), 82 #define GET_GICOMBINER_CONSTRUCTOR_INITS 83 #include "AArch64GenO0PreLegalizeGICombiner.inc" 84 #undef GET_GICOMBINER_CONSTRUCTOR_INITS 85 { 86 } 87 88 bool AArch64O0PreLegalizerCombinerImpl::tryCombineAll(MachineInstr &MI) const { 89 if (tryCombineAllImpl(MI)) 90 return true; 91 92 unsigned Opc = MI.getOpcode(); 93 switch (Opc) { 94 case TargetOpcode::G_SHUFFLE_VECTOR: 95 return Helper.tryCombineShuffleVector(MI); 96 case TargetOpcode::G_MEMCPY_INLINE: 97 return Helper.tryEmitMemcpyInline(MI); 98 case TargetOpcode::G_MEMCPY: 99 case TargetOpcode::G_MEMMOVE: 100 case TargetOpcode::G_MEMSET: { 101 // At -O0 set a maxlen of 32 to inline; 102 unsigned MaxLen = 32; 103 // Try to inline memcpy type calls if optimizations are enabled. 104 if (Helper.tryCombineMemCpyFamily(MI, MaxLen)) 105 return true; 106 if (Opc == TargetOpcode::G_MEMSET) 107 return llvm::AArch64GISelUtils::tryEmitBZero(MI, B, CInfo.EnableMinSize); 108 return false; 109 } 110 } 111 112 return false; 113 } 114 115 // Pass boilerplate 116 // ================ 117 118 class AArch64O0PreLegalizerCombiner : public MachineFunctionPass { 119 public: 120 static char ID; 121 122 AArch64O0PreLegalizerCombiner(); 123 124 StringRef getPassName() const override { 125 return "AArch64O0PreLegalizerCombiner"; 126 } 127 128 bool runOnMachineFunction(MachineFunction &MF) override; 129 130 void getAnalysisUsage(AnalysisUsage &AU) const override; 131 132 private: 133 AArch64O0PreLegalizerCombinerImplRuleConfig RuleConfig; 134 }; 135 } // end anonymous namespace 136 137 void AArch64O0PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const { 138 AU.addRequired<TargetPassConfig>(); 139 AU.setPreservesCFG(); 140 getSelectionDAGFallbackAnalysisUsage(AU); 141 AU.addRequired<GISelKnownBitsAnalysis>(); 142 AU.addPreserved<GISelKnownBitsAnalysis>(); 143 MachineFunctionPass::getAnalysisUsage(AU); 144 } 145 146 AArch64O0PreLegalizerCombiner::AArch64O0PreLegalizerCombiner() 147 : MachineFunctionPass(ID) { 148 initializeAArch64O0PreLegalizerCombinerPass(*PassRegistry::getPassRegistry()); 149 150 if (!RuleConfig.parseCommandLineOption()) 151 report_fatal_error("Invalid rule identifier"); 152 } 153 154 bool AArch64O0PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) { 155 if (MF.getProperties().hasProperty( 156 MachineFunctionProperties::Property::FailedISel)) 157 return false; 158 auto &TPC = getAnalysis<TargetPassConfig>(); 159 160 const Function &F = MF.getFunction(); 161 GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF); 162 163 const AArch64Subtarget &ST = MF.getSubtarget<AArch64Subtarget>(); 164 165 CombinerInfo CInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false, 166 /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false, 167 F.hasOptSize(), F.hasMinSize()); 168 // Disable fixed-point iteration in the Combiner. This improves compile-time 169 // at the cost of possibly missing optimizations. See PR#94291 for details. 170 CInfo.MaxIterations = 1; 171 172 AArch64O0PreLegalizerCombinerImpl Impl(MF, CInfo, &TPC, *KB, 173 /*CSEInfo*/ nullptr, RuleConfig, ST); 174 return Impl.combineMachineInstrs(); 175 } 176 177 char AArch64O0PreLegalizerCombiner::ID = 0; 178 INITIALIZE_PASS_BEGIN(AArch64O0PreLegalizerCombiner, DEBUG_TYPE, 179 "Combine AArch64 machine instrs before legalization", 180 false, false) 181 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig) 182 INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis) 183 INITIALIZE_PASS_DEPENDENCY(GISelCSEAnalysisWrapperPass) 184 INITIALIZE_PASS_END(AArch64O0PreLegalizerCombiner, DEBUG_TYPE, 185 "Combine AArch64 machine instrs before legalization", false, 186 false) 187 188 namespace llvm { 189 FunctionPass *createAArch64O0PreLegalizerCombiner() { 190 return new AArch64O0PreLegalizerCombiner(); 191 } 192 } // end namespace llvm 193