llvm/lib/Target/Mips/MipsPreLegalizerCombiner.cpp

   1 //=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.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 "MipsLegalizerInfo.h"
  15 #include "MipsTargetMachine.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/GISelKnownBits.h"
  20 #include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
  21 #include "llvm/CodeGen/MachineFunctionPass.h"
  22 #include "llvm/CodeGen/TargetPassConfig.h"
  23 #include "llvm/InitializePasses.h"
  24
  25 #define DEBUG_TYPE "mips-prelegalizer-combiner"
  26
  27 using namespace llvm;
  28
  29 namespace {
  30 struct MipsPreLegalizerCombinerInfo : public CombinerInfo {
  31 public:
  32   MipsPreLegalizerCombinerInfo()
  33       : CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
  34                      /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
  35                      /*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
  36 };
  37
  38 class MipsPreLegalizerCombinerImpl : public Combiner {
  39 protected:
  40   const MipsSubtarget &STI;
  41   // TODO: Make CombinerHelper methods const.
  42   mutable CombinerHelper Helper;
  43
  44 public:
  45   MipsPreLegalizerCombinerImpl(MachineFunction &MF, CombinerInfo &CInfo,
  46                                const TargetPassConfig *TPC, GISelKnownBits &KB,
  47                                GISelCSEInfo *CSEInfo, const MipsSubtarget &STI,
  48                                MachineDominatorTree *MDT,
  49                                const LegalizerInfo *LI)
  50       : Combiner(MF, CInfo, TPC, &KB, CSEInfo), STI(STI),
  51         Helper(Observer, B, /*IsPreLegalize*/ true, &KB, MDT, LI) {}
  52
  53   static const char *getName() { return "MipsPreLegalizerCombiner"; }
  54
  55   void setupGeneratedPerFunctionState(MachineFunction &MF) override {
  56     // TODO: TableGen-erate this class' impl.
  57   }
  58
  59   bool tryCombineAll(MachineInstr &MI) const override {
  60
  61     switch (MI.getOpcode()) {
  62     default:
  63       return false;
  64     case TargetOpcode::G_MEMCPY_INLINE:
  65       return Helper.tryEmitMemcpyInline(MI);
  66     case TargetOpcode::G_LOAD:
  67     case TargetOpcode::G_SEXTLOAD:
  68     case TargetOpcode::G_ZEXTLOAD: {
  69       // Don't attempt to combine non power of 2 loads or unaligned loads when
  70       // subtarget doesn't support them.
  71       auto MMO = *MI.memoperands_begin();
  72       const MipsSubtarget &STI = MI.getMF()->getSubtarget<MipsSubtarget>();
  73       if (!MMO->getSize().hasValue() ||
  74           !isPowerOf2_64(MMO->getSize().getValue()))
  75         return false;
  76       bool isUnaligned = MMO->getAlign() < MMO->getSize().getValue();
  77       if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
  78         return false;
  79
  80       return Helper.tryCombineExtendingLoads(MI);
  81     }
  82     }
  83
  84     return false;
  85   }
  86 };
  87
  88 // Pass boilerplate
  89 // ================
  90
  91 class MipsPreLegalizerCombiner : public MachineFunctionPass {
  92 public:
  93   static char ID;
  94
  95   MipsPreLegalizerCombiner();
  96
  97   StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
  98
  99   bool runOnMachineFunction(MachineFunction &MF) override;
 100
 101   void getAnalysisUsage(AnalysisUsage &AU) const override;
 102 };
 103 } // end anonymous namespace
 104
 105 void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
 106   AU.addRequired<TargetPassConfig>();
 107   AU.addRequired<GISelKnownBitsAnalysis>();
 108   AU.addPreserved<GISelKnownBitsAnalysis>();
 109   AU.setPreservesCFG();
 110   getSelectionDAGFallbackAnalysisUsage(AU);
 111   MachineFunctionPass::getAnalysisUsage(AU);
 112 }
 113
 114 MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
 115   initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
 116 }
 117
 118 bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
 119   if (MF.getProperties().hasProperty(
 120           MachineFunctionProperties::Property::FailedISel))
 121     return false;
 122
 123   auto *TPC = &getAnalysis<TargetPassConfig>();
 124   const MipsSubtarget &ST = MF.getSubtarget<MipsSubtarget>();
 125   const MipsLegalizerInfo *LI =
 126       static_cast<const MipsLegalizerInfo *>(ST.getLegalizerInfo());
 127
 128   GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
 129   MipsPreLegalizerCombinerInfo PCInfo;
 130   MipsPreLegalizerCombinerImpl Impl(MF, PCInfo, TPC, *KB, /*CSEInfo*/ nullptr,
 131                                     ST, /*MDT*/ nullptr, LI);
 132   return Impl.combineMachineInstrs();
 133 }
 134
 135 char MipsPreLegalizerCombiner::ID = 0;
 136 INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
 137                       "Combine Mips machine instrs before legalization", false,
 138                       false)
 139 INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
 140 INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
 141 INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
 142                     "Combine Mips machine instrs before legalization", false,
 143                     false)
 144
 145 namespace llvm {
 146 FunctionPass *createMipsPreLegalizeCombiner() {
 147   return new MipsPreLegalizerCombiner();
 148 }
 149 } // end namespace llvm