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1 //===- BranchFolding.cpp - Fold machine code branch instructions ----------===//
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2 //
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3 // The LLVM Compiler Infrastructure
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4 //
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5 // This file is distributed under the University of Illinois Open Source
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6 // License. See LICENSE.TXT for details.
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7 //
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8 //===----------------------------------------------------------------------===//
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9 //
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10 // This pass forwards branches to unconditional branches to make them branch
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11 // directly to the target block. This pass often results in dead MBB's, which
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12 // it then removes.
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13 //
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14 // Note that this pass must be run after register allocation, it cannot handle
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95
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15 // SSA form. It also must handle virtual registers for targets that emit virtual
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16 // ISA (e.g. NVPTX).
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17 //
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18 //===----------------------------------------------------------------------===//
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19
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20 #include "BranchFolding.h"
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121
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21 #include "llvm/ADT/BitVector.h"
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22 #include "llvm/ADT/DenseMap.h"
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23 #include "llvm/ADT/STLExtras.h"
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121
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24 #include "llvm/ADT/SmallPtrSet.h"
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25 #include "llvm/ADT/SmallSet.h"
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121
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26 #include "llvm/ADT/SmallVector.h"
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27 #include "llvm/ADT/Statistic.h"
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95
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28 #include "llvm/CodeGen/Analysis.h"
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121
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29 #include "llvm/CodeGen/LivePhysRegs.h"
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30 #include "llvm/CodeGen/MachineBasicBlock.h"
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77
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31 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
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32 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
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121
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33 #include "llvm/CodeGen/MachineFunction.h"
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34 #include "llvm/CodeGen/MachineFunctionPass.h"
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121
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35 #include "llvm/CodeGen/MachineInstr.h"
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36 #include "llvm/CodeGen/MachineInstrBuilder.h"
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37 #include "llvm/CodeGen/MachineJumpTableInfo.h"
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120
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38 #include "llvm/CodeGen/MachineLoopInfo.h"
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39 #include "llvm/CodeGen/MachineModuleInfo.h"
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121
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40 #include "llvm/CodeGen/MachineOperand.h"
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41 #include "llvm/CodeGen/MachineRegisterInfo.h"
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134
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42 #include "llvm/CodeGen/TargetInstrInfo.h"
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43 #include "llvm/CodeGen/TargetOpcodes.h"
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120
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44 #include "llvm/CodeGen/TargetPassConfig.h"
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134
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45 #include "llvm/CodeGen/TargetRegisterInfo.h"
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46 #include "llvm/CodeGen/TargetSubtargetInfo.h"
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121
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47 #include "llvm/IR/DebugInfoMetadata.h"
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48 #include "llvm/IR/DebugLoc.h"
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49 #include "llvm/IR/Function.h"
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121
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50 #include "llvm/MC/LaneBitmask.h"
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51 #include "llvm/MC/MCRegisterInfo.h"
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52 #include "llvm/Pass.h"
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53 #include "llvm/Support/BlockFrequency.h"
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54 #include "llvm/Support/BranchProbability.h"
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55 #include "llvm/Support/CommandLine.h"
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56 #include "llvm/Support/Debug.h"
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57 #include "llvm/Support/ErrorHandling.h"
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58 #include "llvm/Support/raw_ostream.h"
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121
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59 #include "llvm/Target/TargetMachine.h"
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60 #include <cassert>
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61 #include <cstddef>
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62 #include <iterator>
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63 #include <numeric>
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64 #include <vector>
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65
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66 using namespace llvm;
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67
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68 #define DEBUG_TYPE "branch-folder"
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77
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69
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70 STATISTIC(NumDeadBlocks, "Number of dead blocks removed");
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71 STATISTIC(NumBranchOpts, "Number of branches optimized");
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72 STATISTIC(NumTailMerge , "Number of block tails merged");
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73 STATISTIC(NumHoist , "Number of times common instructions are hoisted");
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120
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74 STATISTIC(NumTailCalls, "Number of tail calls optimized");
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75
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76 static cl::opt<cl::boolOrDefault> FlagEnableTailMerge("enable-tail-merge",
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77 cl::init(cl::BOU_UNSET), cl::Hidden);
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78
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79 // Throttle for huge numbers of predecessors (compile speed problems)
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80 static cl::opt<unsigned>
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81 TailMergeThreshold("tail-merge-threshold",
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82 cl::desc("Max number of predecessors to consider tail merging"),
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83 cl::init(150), cl::Hidden);
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84
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85 // Heuristic for tail merging (and, inversely, tail duplication).
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86 // TODO: This should be replaced with a target query.
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87 static cl::opt<unsigned>
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88 TailMergeSize("tail-merge-size",
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89 cl::desc("Min number of instructions to consider tail merging"),
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90 cl::init(3), cl::Hidden);
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91
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92 namespace {
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121
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93
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94 /// BranchFolderPass - Wrap branch folder in a machine function pass.
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95 class BranchFolderPass : public MachineFunctionPass {
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96 public:
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97 static char ID;
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98
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99 explicit BranchFolderPass(): MachineFunctionPass(ID) {}
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100
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101 bool runOnMachineFunction(MachineFunction &MF) override;
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102
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103 void getAnalysisUsage(AnalysisUsage &AU) const override {
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104 AU.addRequired<MachineBlockFrequencyInfo>();
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105 AU.addRequired<MachineBranchProbabilityInfo>();
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106 AU.addRequired<TargetPassConfig>();
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107 MachineFunctionPass::getAnalysisUsage(AU);
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108 }
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109 };
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121
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110
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111 } // end anonymous namespace
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112
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113 char BranchFolderPass::ID = 0;
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121
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114
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115 char &llvm::BranchFolderPassID = BranchFolderPass::ID;
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116
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121
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117 INITIALIZE_PASS(BranchFolderPass, DEBUG_TYPE,
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118 "Control Flow Optimizer", false, false)
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119
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120 bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) {
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134
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121 if (skipFunction(MF.getFunction()))
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77
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122 return false;
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123
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124 TargetPassConfig *PassConfig = &getAnalysis<TargetPassConfig>();
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33
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125 // TailMerge can create jump into if branches that make CFG irreducible for
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126 // HW that requires structurized CFG.
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127 bool EnableTailMerge = !MF.getTarget().requiresStructuredCFG() &&
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95
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128 PassConfig->getEnableTailMerge();
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120
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129 BranchFolder::MBFIWrapper MBBFreqInfo(
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130 getAnalysis<MachineBlockFrequencyInfo>());
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131 BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true, MBBFreqInfo,
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77
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132 getAnalysis<MachineBranchProbabilityInfo>());
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133 return Folder.OptimizeFunction(MF, MF.getSubtarget().getInstrInfo(),
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134 MF.getSubtarget().getRegisterInfo(),
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135 getAnalysisIfAvailable<MachineModuleInfo>());
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136 }
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137
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77
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138 BranchFolder::BranchFolder(bool defaultEnableTailMerge, bool CommonHoist,
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120
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139 MBFIWrapper &FreqInfo,
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140 const MachineBranchProbabilityInfo &ProbInfo,
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141 unsigned MinTailLength)
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142 : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength),
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143 MBBFreqInfo(FreqInfo), MBPI(ProbInfo) {
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144 if (MinCommonTailLength == 0)
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145 MinCommonTailLength = TailMergeSize;
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146 switch (FlagEnableTailMerge) {
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147 case cl::BOU_UNSET: EnableTailMerge = defaultEnableTailMerge; break;
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148 case cl::BOU_TRUE: EnableTailMerge = true; break;
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149 case cl::BOU_FALSE: EnableTailMerge = false; break;
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150 }
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151 }
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152
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153 void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) {
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154 assert(MBB->pred_empty() && "MBB must be dead!");
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155 DEBUG(dbgs() << "\nRemoving MBB: " << *MBB);
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156
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157 MachineFunction *MF = MBB->getParent();
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158 // drop all successors.
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159 while (!MBB->succ_empty())
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160 MBB->removeSuccessor(MBB->succ_end()-1);
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161
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162 // Avoid matching if this pointer gets reused.
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163 TriedMerging.erase(MBB);
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164
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165 // Remove the block.
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166 MF->erase(MBB);
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95
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167 FuncletMembership.erase(MBB);
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120
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168 if (MLI)
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169 MLI->removeBlock(MBB);
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170 }
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171
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172 bool BranchFolder::OptimizeFunction(MachineFunction &MF,
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173 const TargetInstrInfo *tii,
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174 const TargetRegisterInfo *tri,
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120
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175 MachineModuleInfo *mmi,
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176 MachineLoopInfo *mli, bool AfterPlacement) {
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177 if (!tii) return false;
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178
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179 TriedMerging.clear();
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180
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121
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181 MachineRegisterInfo &MRI = MF.getRegInfo();
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120
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182 AfterBlockPlacement = AfterPlacement;
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183 TII = tii;
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184 TRI = tri;
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185 MMI = mmi;
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120
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186 MLI = mli;
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121
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187 this->MRI = &MRI;
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188
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120
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189 UpdateLiveIns = MRI.tracksLiveness() && TRI->trackLivenessAfterRegAlloc(MF);
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190 if (!UpdateLiveIns)
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191 MRI.invalidateLiveness();
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192
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193 // Fix CFG. The later algorithms expect it to be right.
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194 bool MadeChange = false;
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95
|
195 for (MachineBasicBlock &MBB : MF) {
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|
|
196 MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
197 SmallVector<MachineOperand, 4> Cond;
|
|
120
|
198 if (!TII->analyzeBranch(MBB, TBB, FBB, Cond, true))
|
|
95
|
199 MadeChange |= MBB.CorrectExtraCFGEdges(TBB, FBB, !Cond.empty());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
200 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
201
|
|
95
|
202 // Recalculate funclet membership.
|
|
|
203 FuncletMembership = getFuncletMembership(MF);
|
|
|
204
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
205 bool MadeChangeThisIteration = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
206 while (MadeChangeThisIteration) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
207 MadeChangeThisIteration = TailMergeBlocks(MF);
|
|
120
|
208 // No need to clean up if tail merging does not change anything after the
|
|
|
209 // block placement.
|
|
|
210 if (!AfterBlockPlacement || MadeChangeThisIteration)
|
|
|
211 MadeChangeThisIteration |= OptimizeBranches(MF);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
212 if (EnableHoistCommonCode)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
213 MadeChangeThisIteration |= HoistCommonCode(MF);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
214 MadeChange |= MadeChangeThisIteration;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
215 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
216
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
217 // See if any jump tables have become dead as the code generator
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
218 // did its thing.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
219 MachineJumpTableInfo *JTI = MF.getJumpTableInfo();
|
|
120
|
220 if (!JTI)
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
221 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
222
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
223 // Walk the function to find jump tables that are live.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
224 BitVector JTIsLive(JTI->getJumpTables().size());
|
|
95
|
225 for (const MachineBasicBlock &BB : MF) {
|
|
|
226 for (const MachineInstr &I : BB)
|
|
|
227 for (const MachineOperand &Op : I.operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
228 if (!Op.isJTI()) continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
229
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
230 // Remember that this JT is live.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
231 JTIsLive.set(Op.getIndex());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
232 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
233 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
234
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
235 // Finally, remove dead jump tables. This happens when the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
236 // indirect jump was unreachable (and thus deleted).
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
237 for (unsigned i = 0, e = JTIsLive.size(); i != e; ++i)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
238 if (!JTIsLive.test(i)) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
239 JTI->RemoveJumpTable(i);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
240 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
241 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
242
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
243 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
244 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
245
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
246 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
247 // Tail Merging of Blocks
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
248 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
249
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
250 /// HashMachineInstr - Compute a hash value for MI and its operands.
|
|
120
|
251 static unsigned HashMachineInstr(const MachineInstr &MI) {
|
|
|
252 unsigned Hash = MI.getOpcode();
|
|
|
253 for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
|
|
|
254 const MachineOperand &Op = MI.getOperand(i);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
255
|
|
95
|
256 // Merge in bits from the operand if easy. We can't use MachineOperand's
|
|
|
257 // hash_code here because it's not deterministic and we sort by hash value
|
|
|
258 // later.
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
259 unsigned OperandHash = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
260 switch (Op.getType()) {
|
|
95
|
261 case MachineOperand::MO_Register:
|
|
|
262 OperandHash = Op.getReg();
|
|
|
263 break;
|
|
|
264 case MachineOperand::MO_Immediate:
|
|
|
265 OperandHash = Op.getImm();
|
|
|
266 break;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
267 case MachineOperand::MO_MachineBasicBlock:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
268 OperandHash = Op.getMBB()->getNumber();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
269 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
270 case MachineOperand::MO_FrameIndex:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
271 case MachineOperand::MO_ConstantPoolIndex:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
272 case MachineOperand::MO_JumpTableIndex:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
273 OperandHash = Op.getIndex();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
274 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
275 case MachineOperand::MO_GlobalAddress:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
276 case MachineOperand::MO_ExternalSymbol:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
277 // Global address / external symbol are too hard, don't bother, but do
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
278 // pull in the offset.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
279 OperandHash = Op.getOffset();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
280 break;
|
|
95
|
281 default:
|
|
|
282 break;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
283 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
284
|
|
95
|
285 Hash += ((OperandHash << 3) | Op.getType()) << (i & 31);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
286 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
287 return Hash;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
288 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
289
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
290 /// HashEndOfMBB - Hash the last instruction in the MBB.
|
|
120
|
291 static unsigned HashEndOfMBB(const MachineBasicBlock &MBB) {
|
|
|
292 MachineBasicBlock::const_iterator I = MBB.getLastNonDebugInstr();
|
|
|
293 if (I == MBB.end())
|
|
95
|
294 return 0;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
295
|
|
120
|
296 return HashMachineInstr(*I);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
297 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
298
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
299 /// ComputeCommonTailLength - Given two machine basic blocks, compute the number
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
300 /// of instructions they actually have in common together at their end. Return
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
301 /// iterators for the first shared instruction in each block.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
302 static unsigned ComputeCommonTailLength(MachineBasicBlock *MBB1,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
303 MachineBasicBlock *MBB2,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
304 MachineBasicBlock::iterator &I1,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
305 MachineBasicBlock::iterator &I2) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
306 I1 = MBB1->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
307 I2 = MBB2->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
308
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
309 unsigned TailLen = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
310 while (I1 != MBB1->begin() && I2 != MBB2->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
311 --I1; --I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
312 // Skip debugging pseudos; necessary to avoid changing the code.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
313 while (I1->isDebugValue()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
314 if (I1==MBB1->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
315 while (I2->isDebugValue()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
316 if (I2==MBB2->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
317 // I1==DBG at begin; I2==DBG at begin
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
318 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
319 --I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
320 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
321 ++I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
322 // I1==DBG at begin; I2==non-DBG, or first of DBGs not at begin
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
323 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
324 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
325 --I1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
326 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
327 // I1==first (untested) non-DBG preceding known match
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
328 while (I2->isDebugValue()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
329 if (I2==MBB2->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
330 ++I1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
331 // I1==non-DBG, or first of DBGs not at begin; I2==DBG at begin
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
332 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
333 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
334 --I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
335 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
336 // I1, I2==first (untested) non-DBGs preceding known match
|
|
120
|
337 if (!I1->isIdenticalTo(*I2) ||
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
338 // FIXME: This check is dubious. It's used to get around a problem where
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
339 // people incorrectly expect inline asm directives to remain in the same
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
340 // relative order. This is untenable because normal compiler
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
341 // optimizations (like this one) may reorder and/or merge these
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
342 // directives.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
343 I1->isInlineAsm()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
344 ++I1; ++I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
345 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
346 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
347 ++TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
348 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
349 // Back past possible debugging pseudos at beginning of block. This matters
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
350 // when one block differs from the other only by whether debugging pseudos
|
|
100
|
351 // are present at the beginning. (This way, the various checks later for
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
352 // I1==MBB1->begin() work as expected.)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
353 if (I1 == MBB1->begin() && I2 != MBB2->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
354 --I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
355 while (I2->isDebugValue()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
356 if (I2 == MBB2->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
357 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
358 --I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
359 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
360 ++I2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
361 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
362 if (I2 == MBB2->begin() && I1 != MBB1->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
363 --I1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
364 while (I1->isDebugValue()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
365 if (I1 == MBB1->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
366 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
367 --I1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
368 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
369 ++I1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
370 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
371 return TailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
372 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
373
|
|
121
|
374 void BranchFolder::replaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
|
|
|
375 MachineBasicBlock &NewDest) {
|
|
|
376 if (UpdateLiveIns) {
|
|
|
377 // OldInst should always point to an instruction.
|
|
|
378 MachineBasicBlock &OldMBB = *OldInst->getParent();
|
|
|
379 LiveRegs.clear();
|
|
|
380 LiveRegs.addLiveOuts(OldMBB);
|
|
|
381 // Move backward to the place where will insert the jump.
|
|
|
382 MachineBasicBlock::iterator I = OldMBB.end();
|
|
|
383 do {
|
|
|
384 --I;
|
|
|
385 LiveRegs.stepBackward(*I);
|
|
|
386 } while (I != OldInst);
|
|
120
|
387
|
|
121
|
388 // Merging the tails may have switched some undef operand to non-undef ones.
|
|
|
389 // Add IMPLICIT_DEFS into OldMBB as necessary to have a definition of the
|
|
|
390 // register.
|
|
|
391 for (MachineBasicBlock::RegisterMaskPair P : NewDest.liveins()) {
|
|
|
392 // We computed the liveins with computeLiveIn earlier and should only see
|
|
|
393 // full registers:
|
|
|
394 assert(P.LaneMask == LaneBitmask::getAll() &&
|
|
|
395 "Can only handle full register.");
|
|
|
396 MCPhysReg Reg = P.PhysReg;
|
|
|
397 if (!LiveRegs.available(*MRI, Reg))
|
|
|
398 continue;
|
|
|
399 DebugLoc DL;
|
|
|
400 BuildMI(OldMBB, OldInst, DL, TII->get(TargetOpcode::IMPLICIT_DEF), Reg);
|
|
120
|
401 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
402 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
403
|
|
121
|
404 TII->ReplaceTailWithBranchTo(OldInst, &NewDest);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
405 ++NumTailMerge;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
406 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
407
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
408 MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
409 MachineBasicBlock::iterator BBI1,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
410 const BasicBlock *BB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
411 if (!TII->isLegalToSplitMBBAt(CurMBB, BBI1))
|
|
77
|
412 return nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
413
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
414 MachineFunction &MF = *CurMBB.getParent();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
415
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
416 // Create the fall-through block.
|
|
95
|
417 MachineFunction::iterator MBBI = CurMBB.getIterator();
|
|
121
|
418 MachineBasicBlock *NewMBB = MF.CreateMachineBasicBlock(BB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
419 CurMBB.getParent()->insert(++MBBI, NewMBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
420
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
421 // Move all the successors of this block to the specified block.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
422 NewMBB->transferSuccessors(&CurMBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
423
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
424 // Add an edge from CurMBB to NewMBB for the fall-through.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
425 CurMBB.addSuccessor(NewMBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
426
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
427 // Splice the code over.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
428 NewMBB->splice(NewMBB->end(), &CurMBB, BBI1, CurMBB.end());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
429
|
|
120
|
430 // NewMBB belongs to the same loop as CurMBB.
|
|
121
|
431 if (MLI)
|
|
120
|
432 if (MachineLoop *ML = MLI->getLoopFor(&CurMBB))
|
|
|
433 ML->addBasicBlockToLoop(NewMBB, MLI->getBase());
|
|
|
434
|
|
77
|
435 // NewMBB inherits CurMBB's block frequency.
|
|
|
436 MBBFreqInfo.setBlockFreq(NewMBB, MBBFreqInfo.getBlockFreq(&CurMBB));
|
|
|
437
|
|
121
|
438 if (UpdateLiveIns)
|
|
|
439 computeAndAddLiveIns(LiveRegs, *NewMBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
440
|
|
95
|
441 // Add the new block to the funclet.
|
|
|
442 const auto &FuncletI = FuncletMembership.find(&CurMBB);
|
|
120
|
443 if (FuncletI != FuncletMembership.end()) {
|
|
|
444 auto n = FuncletI->second;
|
|
|
445 FuncletMembership[NewMBB] = n;
|
|
|
446 }
|
|
95
|
447
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
448 return NewMBB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
449 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
450
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
451 /// EstimateRuntime - Make a rough estimate for how long it will take to run
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
452 /// the specified code.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
453 static unsigned EstimateRuntime(MachineBasicBlock::iterator I,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
454 MachineBasicBlock::iterator E) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
455 unsigned Time = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
456 for (; I != E; ++I) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
457 if (I->isDebugValue())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
458 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
459 if (I->isCall())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
460 Time += 10;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
461 else if (I->mayLoad() || I->mayStore())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
462 Time += 2;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
463 else
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
464 ++Time;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
465 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
466 return Time;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
467 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
468
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
469 // CurMBB needs to add an unconditional branch to SuccMBB (we removed these
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
470 // branches temporarily for tail merging). In the case where CurMBB ends
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
471 // with a conditional branch to the next block, optimize by reversing the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
472 // test and conditionally branching to SuccMBB instead.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
473 static void FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
474 const TargetInstrInfo *TII) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
475 MachineFunction *MF = CurMBB->getParent();
|
|
77
|
476 MachineFunction::iterator I = std::next(MachineFunction::iterator(CurMBB));
|
|
|
477 MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
478 SmallVector<MachineOperand, 4> Cond;
|
|
121
|
479 DebugLoc dl = CurMBB->findBranchDebugLoc();
|
|
120
|
480 if (I != MF->end() && !TII->analyzeBranch(*CurMBB, TBB, FBB, Cond, true)) {
|
|
95
|
481 MachineBasicBlock *NextBB = &*I;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
482 if (TBB == NextBB && !Cond.empty() && !FBB) {
|
|
120
|
483 if (!TII->reverseBranchCondition(Cond)) {
|
|
|
484 TII->removeBranch(*CurMBB);
|
|
|
485 TII->insertBranch(*CurMBB, SuccBB, nullptr, Cond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
486 return;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
487 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
488 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
489 }
|
|
120
|
490 TII->insertBranch(*CurMBB, SuccBB, nullptr,
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
491 SmallVector<MachineOperand, 0>(), dl);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
492 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
493
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
494 bool
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
495 BranchFolder::MergePotentialsElt::operator<(const MergePotentialsElt &o) const {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
496 if (getHash() < o.getHash())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
497 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
498 if (getHash() > o.getHash())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
499 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
500 if (getBlock()->getNumber() < o.getBlock()->getNumber())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
501 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
502 if (getBlock()->getNumber() > o.getBlock()->getNumber())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
503 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
504 // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
505 // an object with itself.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
506 #ifndef _GLIBCXX_DEBUG
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
507 llvm_unreachable("Predecessor appears twice");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
508 #else
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
509 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
510 #endif
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
511 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
512
|
|
77
|
513 BlockFrequency
|
|
|
514 BranchFolder::MBFIWrapper::getBlockFreq(const MachineBasicBlock *MBB) const {
|
|
|
515 auto I = MergedBBFreq.find(MBB);
|
|
|
516
|
|
|
517 if (I != MergedBBFreq.end())
|
|
|
518 return I->second;
|
|
|
519
|
|
|
520 return MBFI.getBlockFreq(MBB);
|
|
|
521 }
|
|
|
522
|
|
|
523 void BranchFolder::MBFIWrapper::setBlockFreq(const MachineBasicBlock *MBB,
|
|
|
524 BlockFrequency F) {
|
|
|
525 MergedBBFreq[MBB] = F;
|
|
|
526 }
|
|
|
527
|
|
120
|
528 raw_ostream &
|
|
|
529 BranchFolder::MBFIWrapper::printBlockFreq(raw_ostream &OS,
|
|
|
530 const MachineBasicBlock *MBB) const {
|
|
|
531 return MBFI.printBlockFreq(OS, getBlockFreq(MBB));
|
|
|
532 }
|
|
|
533
|
|
|
534 raw_ostream &
|
|
|
535 BranchFolder::MBFIWrapper::printBlockFreq(raw_ostream &OS,
|
|
|
536 const BlockFrequency Freq) const {
|
|
|
537 return MBFI.printBlockFreq(OS, Freq);
|
|
|
538 }
|
|
|
539
|
|
121
|
540 void BranchFolder::MBFIWrapper::view(const Twine &Name, bool isSimple) {
|
|
|
541 MBFI.view(Name, isSimple);
|
|
|
542 }
|
|
|
543
|
|
|
544 uint64_t
|
|
|
545 BranchFolder::MBFIWrapper::getEntryFreq() const {
|
|
|
546 return MBFI.getEntryFreq();
|
|
|
547 }
|
|
|
548
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
549 /// CountTerminators - Count the number of terminators in the given
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
550 /// block and set I to the position of the first non-terminator, if there
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
551 /// is one, or MBB->end() otherwise.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
552 static unsigned CountTerminators(MachineBasicBlock *MBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
553 MachineBasicBlock::iterator &I) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
554 I = MBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
555 unsigned NumTerms = 0;
|
|
121
|
556 while (true) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
557 if (I == MBB->begin()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
558 I = MBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
559 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
560 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
561 --I;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
562 if (!I->isTerminator()) break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
563 ++NumTerms;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
564 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
565 return NumTerms;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
566 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
567
|
|
121
|
568 /// A no successor, non-return block probably ends in unreachable and is cold.
|
|
|
569 /// Also consider a block that ends in an indirect branch to be a return block,
|
|
|
570 /// since many targets use plain indirect branches to return.
|
|
|
571 static bool blockEndsInUnreachable(const MachineBasicBlock *MBB) {
|
|
|
572 if (!MBB->succ_empty())
|
|
|
573 return false;
|
|
|
574 if (MBB->empty())
|
|
|
575 return true;
|
|
|
576 return !(MBB->back().isReturn() || MBB->back().isIndirectBranch());
|
|
|
577 }
|
|
|
578
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
579 /// ProfitableToMerge - Check if two machine basic blocks have a common tail
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
580 /// and decide if it would be profitable to merge those tails. Return the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
581 /// length of the common tail and iterators to the first common instruction
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
582 /// in each block.
|
|
120
|
583 /// MBB1, MBB2 The blocks to check
|
|
|
584 /// MinCommonTailLength Minimum size of tail block to be merged.
|
|
|
585 /// CommonTailLen Out parameter to record the size of the shared tail between
|
|
|
586 /// MBB1 and MBB2
|
|
|
587 /// I1, I2 Iterator references that will be changed to point to the first
|
|
|
588 /// instruction in the common tail shared by MBB1,MBB2
|
|
|
589 /// SuccBB A common successor of MBB1, MBB2 which are in a canonical form
|
|
|
590 /// relative to SuccBB
|
|
|
591 /// PredBB The layout predecessor of SuccBB, if any.
|
|
|
592 /// FuncletMembership map from block to funclet #.
|
|
|
593 /// AfterPlacement True if we are merging blocks after layout. Stricter
|
|
|
594 /// thresholds apply to prevent undoing tail-duplication.
|
|
95
|
595 static bool
|
|
|
596 ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
|
|
120
|
597 unsigned MinCommonTailLength, unsigned &CommonTailLen,
|
|
95
|
598 MachineBasicBlock::iterator &I1,
|
|
|
599 MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB,
|
|
|
600 MachineBasicBlock *PredBB,
|
|
120
|
601 DenseMap<const MachineBasicBlock *, int> &FuncletMembership,
|
|
|
602 bool AfterPlacement) {
|
|
95
|
603 // It is never profitable to tail-merge blocks from two different funclets.
|
|
|
604 if (!FuncletMembership.empty()) {
|
|
|
605 auto Funclet1 = FuncletMembership.find(MBB1);
|
|
|
606 assert(Funclet1 != FuncletMembership.end());
|
|
|
607 auto Funclet2 = FuncletMembership.find(MBB2);
|
|
|
608 assert(Funclet2 != FuncletMembership.end());
|
|
|
609 if (Funclet1->second != Funclet2->second)
|
|
|
610 return false;
|
|
|
611 }
|
|
|
612
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
613 CommonTailLen = ComputeCommonTailLength(MBB1, MBB2, I1, I2);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
614 if (CommonTailLen == 0)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
615 return false;
|
|
134
|
616 DEBUG(dbgs() << "Common tail length of " << printMBBReference(*MBB1)
|
|
|
617 << " and " << printMBBReference(*MBB2) << " is " << CommonTailLen
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
618 << '\n');
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
619
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
620 // It's almost always profitable to merge any number of non-terminator
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
621 // instructions with the block that falls through into the common successor.
|
|
120
|
622 // This is true only for a single successor. For multiple successors, we are
|
|
|
623 // trading a conditional branch for an unconditional one.
|
|
|
624 // TODO: Re-visit successor size for non-layout tail merging.
|
|
|
625 if ((MBB1 == PredBB || MBB2 == PredBB) &&
|
|
|
626 (!AfterPlacement || MBB1->succ_size() == 1)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
627 MachineBasicBlock::iterator I;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
628 unsigned NumTerms = CountTerminators(MBB1 == PredBB ? MBB2 : MBB1, I);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
629 if (CommonTailLen > NumTerms)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
630 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
631 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
632
|
|
121
|
633 // If these are identical non-return blocks with no successors, merge them.
|
|
|
634 // Such blocks are typically cold calls to noreturn functions like abort, and
|
|
|
635 // are unlikely to become a fallthrough target after machine block placement.
|
|
|
636 // Tail merging these blocks is unlikely to create additional unconditional
|
|
|
637 // branches, and will reduce the size of this cold code.
|
|
|
638 if (I1 == MBB1->begin() && I2 == MBB2->begin() &&
|
|
|
639 blockEndsInUnreachable(MBB1) && blockEndsInUnreachable(MBB2))
|
|
|
640 return true;
|
|
|
641
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
642 // If one of the blocks can be completely merged and happens to be in
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
643 // a position where the other could fall through into it, merge any number
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
644 // of instructions, because it can be done without a branch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
645 // TODO: If the blocks are not adjacent, move one of them so that they are?
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
646 if (MBB1->isLayoutSuccessor(MBB2) && I2 == MBB2->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
647 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
648 if (MBB2->isLayoutSuccessor(MBB1) && I1 == MBB1->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
649 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
650
|
|
121
|
651 // If both blocks are identical and end in a branch, merge them unless they
|
|
|
652 // both have a fallthrough predecessor and successor.
|
|
|
653 // We can only do this after block placement because it depends on whether
|
|
|
654 // there are fallthroughs, and we don't know until after layout.
|
|
|
655 if (AfterPlacement && I1 == MBB1->begin() && I2 == MBB2->begin()) {
|
|
|
656 auto BothFallThrough = [](MachineBasicBlock *MBB) {
|
|
|
657 if (MBB->succ_size() != 0 && !MBB->canFallThrough())
|
|
|
658 return false;
|
|
|
659 MachineFunction::iterator I(MBB);
|
|
|
660 MachineFunction *MF = MBB->getParent();
|
|
|
661 return (MBB != &*MF->begin()) && std::prev(I)->canFallThrough();
|
|
|
662 };
|
|
|
663 if (!BothFallThrough(MBB1) || !BothFallThrough(MBB2))
|
|
|
664 return true;
|
|
|
665 }
|
|
|
666
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
667 // If both blocks have an unconditional branch temporarily stripped out,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
668 // count that as an additional common instruction for the following
|
|
120
|
669 // heuristics. This heuristic is only accurate for single-succ blocks, so to
|
|
|
670 // make sure that during layout merging and duplicating don't crash, we check
|
|
|
671 // for that when merging during layout.
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
672 unsigned EffectiveTailLen = CommonTailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
673 if (SuccBB && MBB1 != PredBB && MBB2 != PredBB &&
|
|
120
|
674 (MBB1->succ_size() == 1 || !AfterPlacement) &&
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
675 !MBB1->back().isBarrier() &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
676 !MBB2->back().isBarrier())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
677 ++EffectiveTailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
678
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
679 // Check if the common tail is long enough to be worthwhile.
|
|
120
|
680 if (EffectiveTailLen >= MinCommonTailLength)
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
681 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
682
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
683 // If we are optimizing for code size, 2 instructions in common is enough if
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
684 // we don't have to split a block. At worst we will be introducing 1 new
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
685 // branch instruction, which is likely to be smaller than the 2
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
686 // instructions that would be deleted in the merge.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
687 MachineFunction *MF = MBB1->getParent();
|
|
134
|
688 return EffectiveTailLen >= 2 && MF->getFunction().optForSize() &&
|
|
100
|
689 (I1 == MBB1->begin() || I2 == MBB2->begin());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
690 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
691
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
692 unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
|
|
120
|
693 unsigned MinCommonTailLength,
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
694 MachineBasicBlock *SuccBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
695 MachineBasicBlock *PredBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
696 unsigned maxCommonTailLength = 0U;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
697 SameTails.clear();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
698 MachineBasicBlock::iterator TrialBBI1, TrialBBI2;
|
|
77
|
699 MPIterator HighestMPIter = std::prev(MergePotentials.end());
|
|
|
700 for (MPIterator CurMPIter = std::prev(MergePotentials.end()),
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
701 B = MergePotentials.begin();
|
|
77
|
702 CurMPIter != B && CurMPIter->getHash() == CurHash; --CurMPIter) {
|
|
|
703 for (MPIterator I = std::prev(CurMPIter); I->getHash() == CurHash; --I) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
704 unsigned CommonTailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
705 if (ProfitableToMerge(CurMPIter->getBlock(), I->getBlock(),
|
|
120
|
706 MinCommonTailLength,
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
707 CommonTailLen, TrialBBI1, TrialBBI2,
|
|
95
|
708 SuccBB, PredBB,
|
|
120
|
709 FuncletMembership,
|
|
|
710 AfterBlockPlacement)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
711 if (CommonTailLen > maxCommonTailLength) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
712 SameTails.clear();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
713 maxCommonTailLength = CommonTailLen;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
714 HighestMPIter = CurMPIter;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
715 SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1));
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
716 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
717 if (HighestMPIter == CurMPIter &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
718 CommonTailLen == maxCommonTailLength)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
719 SameTails.push_back(SameTailElt(I, TrialBBI2));
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
720 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
721 if (I == B)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
722 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
723 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
724 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
725 return maxCommonTailLength;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
726 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
727
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
728 void BranchFolder::RemoveBlocksWithHash(unsigned CurHash,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
729 MachineBasicBlock *SuccBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
730 MachineBasicBlock *PredBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
731 MPIterator CurMPIter, B;
|
|
77
|
732 for (CurMPIter = std::prev(MergePotentials.end()),
|
|
|
733 B = MergePotentials.begin();
|
|
|
734 CurMPIter->getHash() == CurHash; --CurMPIter) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
735 // Put the unconditional branch back, if we need one.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
736 MachineBasicBlock *CurMBB = CurMPIter->getBlock();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
737 if (SuccBB && CurMBB != PredBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
738 FixTail(CurMBB, SuccBB, TII);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
739 if (CurMPIter == B)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
740 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
741 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
742 if (CurMPIter->getHash() != CurHash)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
743 CurMPIter++;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
744 MergePotentials.erase(CurMPIter, MergePotentials.end());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
745 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
746
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
747 bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
748 MachineBasicBlock *SuccBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
749 unsigned maxCommonTailLength,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
750 unsigned &commonTailIndex) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
751 commonTailIndex = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
752 unsigned TimeEstimate = ~0U;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
753 for (unsigned i = 0, e = SameTails.size(); i != e; ++i) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
754 // Use PredBB if possible; that doesn't require a new branch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
755 if (SameTails[i].getBlock() == PredBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
756 commonTailIndex = i;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
757 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
758 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
759 // Otherwise, make a (fairly bogus) choice based on estimate of
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
760 // how long it will take the various blocks to execute.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
761 unsigned t = EstimateRuntime(SameTails[i].getBlock()->begin(),
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
762 SameTails[i].getTailStartPos());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
763 if (t <= TimeEstimate) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
764 TimeEstimate = t;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
765 commonTailIndex = i;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
766 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
767 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
768
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
769 MachineBasicBlock::iterator BBI =
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
770 SameTails[commonTailIndex].getTailStartPos();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
771 MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
772
|
|
134
|
773 DEBUG(dbgs() << "\nSplitting " << printMBBReference(*MBB) << ", size "
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
774 << maxCommonTailLength);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
775
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
776 // If the split block unconditionally falls-thru to SuccBB, it will be
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
777 // merged. In control flow terms it should then take SuccBB's name. e.g. If
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
778 // SuccBB is an inner loop, the common tail is still part of the inner loop.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
779 const BasicBlock *BB = (SuccBB && MBB->succ_size() == 1) ?
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
780 SuccBB->getBasicBlock() : MBB->getBasicBlock();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
781 MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI, BB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
782 if (!newMBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
783 DEBUG(dbgs() << "... failed!");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
784 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
785 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
786
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
787 SameTails[commonTailIndex].setBlock(newMBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
788 SameTails[commonTailIndex].setTailStartPos(newMBB->begin());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
789
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
790 // If we split PredBB, newMBB is the new predecessor.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
791 if (PredBB == MBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
792 PredBB = newMBB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
793
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
794 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
795 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
796
|
|
95
|
797 static void
|
|
120
|
798 mergeOperations(MachineBasicBlock::iterator MBBIStartPos,
|
|
|
799 MachineBasicBlock &MBBCommon) {
|
|
95
|
800 MachineBasicBlock *MBB = MBBIStartPos->getParent();
|
|
|
801 // Note CommonTailLen does not necessarily matches the size of
|
|
|
802 // the common BB nor all its instructions because of debug
|
|
|
803 // instructions differences.
|
|
|
804 unsigned CommonTailLen = 0;
|
|
|
805 for (auto E = MBB->end(); MBBIStartPos != E; ++MBBIStartPos)
|
|
|
806 ++CommonTailLen;
|
|
|
807
|
|
|
808 MachineBasicBlock::reverse_iterator MBBI = MBB->rbegin();
|
|
|
809 MachineBasicBlock::reverse_iterator MBBIE = MBB->rend();
|
|
|
810 MachineBasicBlock::reverse_iterator MBBICommon = MBBCommon.rbegin();
|
|
|
811 MachineBasicBlock::reverse_iterator MBBIECommon = MBBCommon.rend();
|
|
|
812
|
|
|
813 while (CommonTailLen--) {
|
|
|
814 assert(MBBI != MBBIE && "Reached BB end within common tail length!");
|
|
|
815 (void)MBBIE;
|
|
|
816
|
|
|
817 if (MBBI->isDebugValue()) {
|
|
|
818 ++MBBI;
|
|
|
819 continue;
|
|
|
820 }
|
|
|
821
|
|
|
822 while ((MBBICommon != MBBIECommon) && MBBICommon->isDebugValue())
|
|
|
823 ++MBBICommon;
|
|
|
824
|
|
|
825 assert(MBBICommon != MBBIECommon &&
|
|
|
826 "Reached BB end within common tail length!");
|
|
120
|
827 assert(MBBICommon->isIdenticalTo(*MBBI) && "Expected matching MIIs!");
|
|
95
|
828
|
|
120
|
829 // Merge MMOs from memory operations in the common block.
|
|
95
|
830 if (MBBICommon->mayLoad() || MBBICommon->mayStore())
|
|
100
|
831 MBBICommon->setMemRefs(MBBICommon->mergeMemRefsWith(*MBBI));
|
|
120
|
832 // Drop undef flags if they aren't present in all merged instructions.
|
|
|
833 for (unsigned I = 0, E = MBBICommon->getNumOperands(); I != E; ++I) {
|
|
|
834 MachineOperand &MO = MBBICommon->getOperand(I);
|
|
|
835 if (MO.isReg() && MO.isUndef()) {
|
|
|
836 const MachineOperand &OtherMO = MBBI->getOperand(I);
|
|
|
837 if (!OtherMO.isUndef())
|
|
|
838 MO.setIsUndef(false);
|
|
|
839 }
|
|
|
840 }
|
|
95
|
841
|
|
|
842 ++MBBI;
|
|
|
843 ++MBBICommon;
|
|
|
844 }
|
|
|
845 }
|
|
|
846
|
|
121
|
847 void BranchFolder::mergeCommonTails(unsigned commonTailIndex) {
|
|
|
848 MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
|
|
|
849
|
|
|
850 std::vector<MachineBasicBlock::iterator> NextCommonInsts(SameTails.size());
|
|
|
851 for (unsigned int i = 0 ; i != SameTails.size() ; ++i) {
|
|
|
852 if (i != commonTailIndex) {
|
|
|
853 NextCommonInsts[i] = SameTails[i].getTailStartPos();
|
|
|
854 mergeOperations(SameTails[i].getTailStartPos(), *MBB);
|
|
|
855 } else {
|
|
|
856 assert(SameTails[i].getTailStartPos() == MBB->begin() &&
|
|
|
857 "MBB is not a common tail only block");
|
|
|
858 }
|
|
|
859 }
|
|
|
860
|
|
|
861 for (auto &MI : *MBB) {
|
|
|
862 if (MI.isDebugValue())
|
|
|
863 continue;
|
|
|
864 DebugLoc DL = MI.getDebugLoc();
|
|
|
865 for (unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) {
|
|
|
866 if (i == commonTailIndex)
|
|
|
867 continue;
|
|
|
868
|
|
|
869 auto &Pos = NextCommonInsts[i];
|
|
|
870 assert(Pos != SameTails[i].getBlock()->end() &&
|
|
|
871 "Reached BB end within common tail");
|
|
|
872 while (Pos->isDebugValue()) {
|
|
|
873 ++Pos;
|
|
|
874 assert(Pos != SameTails[i].getBlock()->end() &&
|
|
|
875 "Reached BB end within common tail");
|
|
|
876 }
|
|
|
877 assert(MI.isIdenticalTo(*Pos) && "Expected matching MIIs!");
|
|
|
878 DL = DILocation::getMergedLocation(DL, Pos->getDebugLoc());
|
|
|
879 NextCommonInsts[i] = ++Pos;
|
|
|
880 }
|
|
|
881 MI.setDebugLoc(DL);
|
|
|
882 }
|
|
|
883
|
|
|
884 if (UpdateLiveIns) {
|
|
|
885 LivePhysRegs NewLiveIns(*TRI);
|
|
|
886 computeLiveIns(NewLiveIns, *MBB);
|
|
|
887
|
|
|
888 // The flag merging may lead to some register uses no longer using the
|
|
|
889 // <undef> flag, add IMPLICIT_DEFs in the predecessors as necessary.
|
|
|
890 for (MachineBasicBlock *Pred : MBB->predecessors()) {
|
|
|
891 LiveRegs.init(*TRI);
|
|
|
892 LiveRegs.addLiveOuts(*Pred);
|
|
|
893 MachineBasicBlock::iterator InsertBefore = Pred->getFirstTerminator();
|
|
|
894 for (unsigned Reg : NewLiveIns) {
|
|
|
895 if (!LiveRegs.available(*MRI, Reg))
|
|
|
896 continue;
|
|
|
897 DebugLoc DL;
|
|
|
898 BuildMI(*Pred, InsertBefore, DL, TII->get(TargetOpcode::IMPLICIT_DEF),
|
|
|
899 Reg);
|
|
|
900 }
|
|
|
901 }
|
|
|
902
|
|
|
903 MBB->clearLiveIns();
|
|
|
904 addLiveIns(*MBB, NewLiveIns);
|
|
|
905 }
|
|
|
906 }
|
|
|
907
|
|
120
|
908 // See if any of the blocks in MergePotentials (which all have SuccBB as a
|
|
|
909 // successor, or all have no successor if it is null) can be tail-merged.
|
|
|
910 // If there is a successor, any blocks in MergePotentials that are not
|
|
|
911 // tail-merged and are not immediately before Succ must have an unconditional
|
|
|
912 // branch to Succ added (but the predecessor/successor lists need no
|
|
|
913 // adjustment). The lone predecessor of Succ that falls through into Succ,
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
914 // if any, is given in PredBB.
|
|
120
|
915 // MinCommonTailLength - Except for the special cases below, tail-merge if
|
|
|
916 // there are at least this many instructions in common.
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
917 bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
|
|
120
|
918 MachineBasicBlock *PredBB,
|
|
|
919 unsigned MinCommonTailLength) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
920 bool MadeChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
921
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
922 DEBUG(dbgs() << "\nTryTailMergeBlocks: ";
|
|
134
|
923 for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i) dbgs()
|
|
|
924 << printMBBReference(*MergePotentials[i].getBlock())
|
|
|
925 << (i == e - 1 ? "" : ", ");
|
|
|
926 dbgs() << "\n"; if (SuccBB) {
|
|
|
927 dbgs() << " with successor " << printMBBReference(*SuccBB) << '\n';
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
928 if (PredBB)
|
|
134
|
929 dbgs() << " which has fall-through from "
|
|
|
930 << printMBBReference(*PredBB) << "\n";
|
|
|
931 } dbgs() << "Looking for common tails of at least "
|
|
|
932 << MinCommonTailLength << " instruction"
|
|
|
933 << (MinCommonTailLength == 1 ? "" : "s") << '\n';);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
934
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
935 // Sort by hash value so that blocks with identical end sequences sort
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
936 // together.
|
|
95
|
937 array_pod_sort(MergePotentials.begin(), MergePotentials.end());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
938
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
939 // Walk through equivalence sets looking for actual exact matches.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
940 while (MergePotentials.size() > 1) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
941 unsigned CurHash = MergePotentials.back().getHash();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
942
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
943 // Build SameTails, identifying the set of blocks with this hash code
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
944 // and with the maximum number of instructions in common.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
945 unsigned maxCommonTailLength = ComputeSameTails(CurHash,
|
|
120
|
946 MinCommonTailLength,
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
947 SuccBB, PredBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
948
|
|
120
|
949 // If we didn't find any pair that has at least MinCommonTailLength
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
950 // instructions in common, remove all blocks with this hash code and retry.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
951 if (SameTails.empty()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
952 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
953 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
954 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
955
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
956 // If one of the blocks is the entire common tail (and not the entry
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
957 // block, which we can't jump to), we can treat all blocks with this same
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
958 // tail at once. Use PredBB if that is one of the possibilities, as that
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
959 // will not introduce any extra branches.
|
|
95
|
960 MachineBasicBlock *EntryBB =
|
|
|
961 &MergePotentials.front().getBlock()->getParent()->front();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
962 unsigned commonTailIndex = SameTails.size();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
963 // If there are two blocks, check to see if one can be made to fall through
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
964 // into the other.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
965 if (SameTails.size() == 2 &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
966 SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
967 SameTails[1].tailIsWholeBlock())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
968 commonTailIndex = 1;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
969 else if (SameTails.size() == 2 &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
970 SameTails[1].getBlock()->isLayoutSuccessor(
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
971 SameTails[0].getBlock()) &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
972 SameTails[0].tailIsWholeBlock())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
973 commonTailIndex = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
974 else {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
975 // Otherwise just pick one, favoring the fall-through predecessor if
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
976 // there is one.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
977 for (unsigned i = 0, e = SameTails.size(); i != e; ++i) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
978 MachineBasicBlock *MBB = SameTails[i].getBlock();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
979 if (MBB == EntryBB && SameTails[i].tailIsWholeBlock())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
980 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
981 if (MBB == PredBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
982 commonTailIndex = i;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
983 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
984 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
985 if (SameTails[i].tailIsWholeBlock())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
986 commonTailIndex = i;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
987 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
988 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
989
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
990 if (commonTailIndex == SameTails.size() ||
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
991 (SameTails[commonTailIndex].getBlock() == PredBB &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
992 !SameTails[commonTailIndex].tailIsWholeBlock())) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
993 // None of the blocks consist entirely of the common tail.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
994 // Split a block so that one does.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
995 if (!CreateCommonTailOnlyBlock(PredBB, SuccBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
996 maxCommonTailLength, commonTailIndex)) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
997 RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
998 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
999 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1000 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1001
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1002 MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
|
|
77
|
1003
|
|
120
|
1004 // Recompute common tail MBB's edge weights and block frequency.
|
|
77
|
1005 setCommonTailEdgeWeights(*MBB);
|
|
|
1006
|
|
121
|
1007 // Merge debug locations, MMOs and undef flags across identical instructions
|
|
|
1008 // for common tail.
|
|
|
1009 mergeCommonTails(commonTailIndex);
|
|
120
|
1010
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1011 // MBB is common tail. Adjust all other BB's to jump to this one.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1012 // Traversal must be forwards so erases work.
|
|
134
|
1013 DEBUG(dbgs() << "\nUsing common tail in " << printMBBReference(*MBB)
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1014 << " for ");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1015 for (unsigned int i=0, e = SameTails.size(); i != e; ++i) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1016 if (commonTailIndex == i)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1017 continue;
|
|
134
|
1018 DEBUG(dbgs() << printMBBReference(*SameTails[i].getBlock())
|
|
|
1019 << (i == e - 1 ? "" : ", "));
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1020 // Hack the end off BB i, making it jump to BB commonTailIndex instead.
|
|
121
|
1021 replaceTailWithBranchTo(SameTails[i].getTailStartPos(), *MBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1022 // BB i is no longer a predecessor of SuccBB; remove it from the worklist.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1023 MergePotentials.erase(SameTails[i].getMPIter());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1024 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1025 DEBUG(dbgs() << "\n");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1026 // We leave commonTailIndex in the worklist in case there are other blocks
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1027 // that match it with a smaller number of instructions.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1028 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1029 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1030 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1031 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1032
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1033 bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1034 bool MadeChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1035 if (!EnableTailMerge) return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1036
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1037 // First find blocks with no successors.
|
|
120
|
1038 // Block placement does not create new tail merging opportunities for these
|
|
|
1039 // blocks.
|
|
|
1040 if (!AfterBlockPlacement) {
|
|
|
1041 MergePotentials.clear();
|
|
|
1042 for (MachineBasicBlock &MBB : MF) {
|
|
|
1043 if (MergePotentials.size() == TailMergeThreshold)
|
|
|
1044 break;
|
|
|
1045 if (!TriedMerging.count(&MBB) && MBB.succ_empty())
|
|
|
1046 MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(MBB), &MBB));
|
|
|
1047 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1048
|
|
120
|
1049 // If this is a large problem, avoid visiting the same basic blocks
|
|
|
1050 // multiple times.
|
|
|
1051 if (MergePotentials.size() == TailMergeThreshold)
|
|
|
1052 for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
|
|
|
1053 TriedMerging.insert(MergePotentials[i].getBlock());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1054
|
|
120
|
1055 // See if we can do any tail merging on those.
|
|
|
1056 if (MergePotentials.size() >= 2)
|
|
|
1057 MadeChange |= TryTailMergeBlocks(nullptr, nullptr, MinCommonTailLength);
|
|
|
1058 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1059
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1060 // Look at blocks (IBB) with multiple predecessors (PBB).
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1061 // We change each predecessor to a canonical form, by
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1062 // (1) temporarily removing any unconditional branch from the predecessor
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1063 // to IBB, and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1064 // (2) alter conditional branches so they branch to the other block
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1065 // not IBB; this may require adding back an unconditional branch to IBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1066 // later, where there wasn't one coming in. E.g.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1067 // Bcc IBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1068 // fallthrough to QBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1069 // here becomes
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1070 // Bncc QBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1071 // with a conceptual B to IBB after that, which never actually exists.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1072 // With those changes, we see whether the predecessors' tails match,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1073 // and merge them if so. We change things out of canonical form and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1074 // back to the way they were later in the process. (OptimizeBranches
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1075 // would undo some of this, but we can't use it, because we'd get into
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1076 // a compile-time infinite loop repeatedly doing and undoing the same
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1077 // transformations.)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1078
|
|
77
|
1079 for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1080 I != E; ++I) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1081 if (I->pred_size() < 2) continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1082 SmallPtrSet<MachineBasicBlock *, 8> UniquePreds;
|
|
95
|
1083 MachineBasicBlock *IBB = &*I;
|
|
|
1084 MachineBasicBlock *PredBB = &*std::prev(I);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1085 MergePotentials.clear();
|
|
120
|
1086 MachineLoop *ML;
|
|
|
1087
|
|
|
1088 // Bail if merging after placement and IBB is the loop header because
|
|
|
1089 // -- If merging predecessors that belong to the same loop as IBB, the
|
|
|
1090 // common tail of merged predecessors may become the loop top if block
|
|
|
1091 // placement is called again and the predecessors may branch to this common
|
|
|
1092 // tail and require more branches. This can be relaxed if
|
|
|
1093 // MachineBlockPlacement::findBestLoopTop is more flexible.
|
|
|
1094 // --If merging predecessors that do not belong to the same loop as IBB, the
|
|
|
1095 // loop info of IBB's loop and the other loops may be affected. Calling the
|
|
|
1096 // block placement again may make big change to the layout and eliminate the
|
|
|
1097 // reason to do tail merging here.
|
|
|
1098 if (AfterBlockPlacement && MLI) {
|
|
|
1099 ML = MLI->getLoopFor(IBB);
|
|
|
1100 if (ML && IBB == ML->getHeader())
|
|
|
1101 continue;
|
|
|
1102 }
|
|
|
1103
|
|
95
|
1104 for (MachineBasicBlock *PBB : I->predecessors()) {
|
|
|
1105 if (MergePotentials.size() == TailMergeThreshold)
|
|
|
1106 break;
|
|
|
1107
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1108 if (TriedMerging.count(PBB))
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1109 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1110
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1111 // Skip blocks that loop to themselves, can't tail merge these.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1112 if (PBB == IBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1113 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1114
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1115 // Visit each predecessor only once.
|
|
83
|
1116 if (!UniquePreds.insert(PBB).second)
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1117 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1118
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1119 // Skip blocks which may jump to a landing pad. Can't tail merge these.
|
|
95
|
1120 if (PBB->hasEHPadSuccessor())
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1121 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1122
|
|
120
|
1123 // After block placement, only consider predecessors that belong to the
|
|
|
1124 // same loop as IBB. The reason is the same as above when skipping loop
|
|
|
1125 // header.
|
|
|
1126 if (AfterBlockPlacement && MLI)
|
|
|
1127 if (ML != MLI->getLoopFor(PBB))
|
|
|
1128 continue;
|
|
|
1129
|
|
77
|
1130 MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1131 SmallVector<MachineOperand, 4> Cond;
|
|
120
|
1132 if (!TII->analyzeBranch(*PBB, TBB, FBB, Cond, true)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1133 // Failing case: IBB is the target of a cbr, and we cannot reverse the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1134 // branch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1135 SmallVector<MachineOperand, 4> NewCond(Cond);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1136 if (!Cond.empty() && TBB == IBB) {
|
|
120
|
1137 if (TII->reverseBranchCondition(NewCond))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1138 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1139 // This is the QBB case described above
|
|
95
|
1140 if (!FBB) {
|
|
|
1141 auto Next = ++PBB->getIterator();
|
|
|
1142 if (Next != MF.end())
|
|
|
1143 FBB = &*Next;
|
|
|
1144 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1145 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1146
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1147 // Failing case: the only way IBB can be reached from PBB is via
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1148 // exception handling. Happens for landing pads. Would be nice to have
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1149 // a bit in the edge so we didn't have to do all this.
|
|
95
|
1150 if (IBB->isEHPad()) {
|
|
|
1151 MachineFunction::iterator IP = ++PBB->getIterator();
|
|
77
|
1152 MachineBasicBlock *PredNextBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1153 if (IP != MF.end())
|
|
95
|
1154 PredNextBB = &*IP;
|
|
77
|
1155 if (!TBB) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1156 if (IBB != PredNextBB) // fallthrough
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1157 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1158 } else if (FBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1159 if (TBB != IBB && FBB != IBB) // cbr then ubr
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1160 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1161 } else if (Cond.empty()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1162 if (TBB != IBB) // ubr
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1163 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1164 } else {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1165 if (TBB != IBB && IBB != PredNextBB) // cbr
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1166 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1167 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1168 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1169
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1170 // Remove the unconditional branch at the end, if any.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1171 if (TBB && (Cond.empty() || FBB)) {
|
|
121
|
1172 DebugLoc dl = PBB->findBranchDebugLoc();
|
|
120
|
1173 TII->removeBranch(*PBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1174 if (!Cond.empty())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1175 // reinsert conditional branch only, for now
|
|
120
|
1176 TII->insertBranch(*PBB, (TBB == IBB) ? FBB : TBB, nullptr,
|
|
77
|
1177 NewCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1178 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1179
|
|
120
|
1180 MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(*PBB), PBB));
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1181 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1182 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1183
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1184 // If this is a large problem, avoid visiting the same basic blocks multiple
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1185 // times.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1186 if (MergePotentials.size() == TailMergeThreshold)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1187 for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1188 TriedMerging.insert(MergePotentials[i].getBlock());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1189
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1190 if (MergePotentials.size() >= 2)
|
|
120
|
1191 MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1192
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1193 // Reinsert an unconditional branch if needed. The 1 below can occur as a
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1194 // result of removing blocks in TryTailMergeBlocks.
|
|
95
|
1195 PredBB = &*std::prev(I); // this may have been changed in TryTailMergeBlocks
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1196 if (MergePotentials.size() == 1 &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1197 MergePotentials.begin()->getBlock() != PredBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1198 FixTail(MergePotentials.begin()->getBlock(), IBB, TII);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1199 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1200
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1201 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1202 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1203
|
|
77
|
1204 void BranchFolder::setCommonTailEdgeWeights(MachineBasicBlock &TailMBB) {
|
|
|
1205 SmallVector<BlockFrequency, 2> EdgeFreqLs(TailMBB.succ_size());
|
|
|
1206 BlockFrequency AccumulatedMBBFreq;
|
|
|
1207
|
|
|
1208 // Aggregate edge frequency of successor edge j:
|
|
|
1209 // edgeFreq(j) = sum (freq(bb) * edgeProb(bb, j)),
|
|
|
1210 // where bb is a basic block that is in SameTails.
|
|
|
1211 for (const auto &Src : SameTails) {
|
|
|
1212 const MachineBasicBlock *SrcMBB = Src.getBlock();
|
|
|
1213 BlockFrequency BlockFreq = MBBFreqInfo.getBlockFreq(SrcMBB);
|
|
|
1214 AccumulatedMBBFreq += BlockFreq;
|
|
|
1215
|
|
|
1216 // It is not necessary to recompute edge weights if TailBB has less than two
|
|
|
1217 // successors.
|
|
|
1218 if (TailMBB.succ_size() <= 1)
|
|
|
1219 continue;
|
|
|
1220
|
|
|
1221 auto EdgeFreq = EdgeFreqLs.begin();
|
|
|
1222
|
|
|
1223 for (auto SuccI = TailMBB.succ_begin(), SuccE = TailMBB.succ_end();
|
|
|
1224 SuccI != SuccE; ++SuccI, ++EdgeFreq)
|
|
|
1225 *EdgeFreq += BlockFreq * MBPI.getEdgeProbability(SrcMBB, *SuccI);
|
|
|
1226 }
|
|
|
1227
|
|
|
1228 MBBFreqInfo.setBlockFreq(&TailMBB, AccumulatedMBBFreq);
|
|
|
1229
|
|
|
1230 if (TailMBB.succ_size() <= 1)
|
|
|
1231 return;
|
|
|
1232
|
|
100
|
1233 auto SumEdgeFreq =
|
|
|
1234 std::accumulate(EdgeFreqLs.begin(), EdgeFreqLs.end(), BlockFrequency(0))
|
|
|
1235 .getFrequency();
|
|
77
|
1236 auto EdgeFreq = EdgeFreqLs.begin();
|
|
|
1237
|
|
100
|
1238 if (SumEdgeFreq > 0) {
|
|
|
1239 for (auto SuccI = TailMBB.succ_begin(), SuccE = TailMBB.succ_end();
|
|
|
1240 SuccI != SuccE; ++SuccI, ++EdgeFreq) {
|
|
|
1241 auto Prob = BranchProbability::getBranchProbability(
|
|
|
1242 EdgeFreq->getFrequency(), SumEdgeFreq);
|
|
|
1243 TailMBB.setSuccProbability(SuccI, Prob);
|
|
|
1244 }
|
|
|
1245 }
|
|
77
|
1246 }
|
|
|
1247
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1248 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1249 // Branch Optimization
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1250 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1251
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1252 bool BranchFolder::OptimizeBranches(MachineFunction &MF) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1253 bool MadeChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1254
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1255 // Make sure blocks are numbered in order
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1256 MF.RenumberBlocks();
|
|
95
|
1257 // Renumbering blocks alters funclet membership, recalculate it.
|
|
|
1258 FuncletMembership = getFuncletMembership(MF);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1259
|
|
77
|
1260 for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1261 I != E; ) {
|
|
95
|
1262 MachineBasicBlock *MBB = &*I++;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1263 MadeChange |= OptimizeBlock(MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1264
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1265 // If it is dead, remove it.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1266 if (MBB->pred_empty()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1267 RemoveDeadBlock(MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1268 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1269 ++NumDeadBlocks;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1270 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1271 }
|
|
95
|
1272
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1273 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1274 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1275
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1276 // Blocks should be considered empty if they contain only debug info;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1277 // else the debug info would affect codegen.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1278 static bool IsEmptyBlock(MachineBasicBlock *MBB) {
|
|
95
|
1279 return MBB->getFirstNonDebugInstr() == MBB->end();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1280 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1281
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1282 // Blocks with only debug info and branches should be considered the same
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1283 // as blocks with only branches.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1284 static bool IsBranchOnlyBlock(MachineBasicBlock *MBB) {
|
|
95
|
1285 MachineBasicBlock::iterator I = MBB->getFirstNonDebugInstr();
|
|
|
1286 assert(I != MBB->end() && "empty block!");
|
|
|
1287 return I->isBranch();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1288 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1289
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1290 /// IsBetterFallthrough - Return true if it would be clearly better to
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1291 /// fall-through to MBB1 than to fall through into MBB2. This has to return
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1292 /// a strict ordering, returning true for both (MBB1,MBB2) and (MBB2,MBB1) will
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1293 /// result in infinite loops.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1294 static bool IsBetterFallthrough(MachineBasicBlock *MBB1,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1295 MachineBasicBlock *MBB2) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1296 // Right now, we use a simple heuristic. If MBB2 ends with a call, and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1297 // MBB1 doesn't, we prefer to fall through into MBB1. This allows us to
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1298 // optimize branches that branch to either a return block or an assert block
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1299 // into a fallthrough to the return.
|
|
95
|
1300 MachineBasicBlock::iterator MBB1I = MBB1->getLastNonDebugInstr();
|
|
|
1301 MachineBasicBlock::iterator MBB2I = MBB2->getLastNonDebugInstr();
|
|
|
1302 if (MBB1I == MBB1->end() || MBB2I == MBB2->end())
|
|
|
1303 return false;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1304
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1305 // If there is a clear successor ordering we make sure that one block
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1306 // will fall through to the next
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1307 if (MBB1->isSuccessor(MBB2)) return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1308 if (MBB2->isSuccessor(MBB1)) return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1309
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1310 return MBB2I->isCall() && !MBB1I->isCall();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1311 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1312
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1313 /// getBranchDebugLoc - Find and return, if any, the DebugLoc of the branch
|
|
95
|
1314 /// instructions on the block.
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1315 static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB) {
|
|
95
|
1316 MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr();
|
|
|
1317 if (I != MBB.end() && I->isBranch())
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1318 return I->getDebugLoc();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1319 return DebugLoc();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1320 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1321
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1322 bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1323 bool MadeChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1324 MachineFunction &MF = *MBB->getParent();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1325 ReoptimizeBlock:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1326
|
|
95
|
1327 MachineFunction::iterator FallThrough = MBB->getIterator();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1328 ++FallThrough;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1329
|
|
95
|
1330 // Make sure MBB and FallThrough belong to the same funclet.
|
|
|
1331 bool SameFunclet = true;
|
|
|
1332 if (!FuncletMembership.empty() && FallThrough != MF.end()) {
|
|
|
1333 auto MBBFunclet = FuncletMembership.find(MBB);
|
|
|
1334 assert(MBBFunclet != FuncletMembership.end());
|
|
|
1335 auto FallThroughFunclet = FuncletMembership.find(&*FallThrough);
|
|
|
1336 assert(FallThroughFunclet != FuncletMembership.end());
|
|
|
1337 SameFunclet = MBBFunclet->second == FallThroughFunclet->second;
|
|
|
1338 }
|
|
|
1339
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1340 // If this block is empty, make everyone use its fall-through, not the block
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1341 // explicitly. Landing pads should not do this since the landing-pad table
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1342 // points to this block. Blocks with their addresses taken shouldn't be
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1343 // optimized away.
|
|
95
|
1344 if (IsEmptyBlock(MBB) && !MBB->isEHPad() && !MBB->hasAddressTaken() &&
|
|
|
1345 SameFunclet) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1346 // Dead block? Leave for cleanup later.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1347 if (MBB->pred_empty()) return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1348
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1349 if (FallThrough == MF.end()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1350 // TODO: Simplify preds to not branch here if possible!
|
|
95
|
1351 } else if (FallThrough->isEHPad()) {
|
|
|
1352 // Don't rewrite to a landing pad fallthough. That could lead to the case
|
|
|
1353 // where a BB jumps to more than one landing pad.
|
|
|
1354 // TODO: Is it ever worth rewriting predecessors which don't already
|
|
|
1355 // jump to a landing pad, and so can safely jump to the fallthrough?
|
|
120
|
1356 } else if (MBB->isSuccessor(&*FallThrough)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1357 // Rewrite all predecessors of the old block to go to the fallthrough
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1358 // instead.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1359 while (!MBB->pred_empty()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1360 MachineBasicBlock *Pred = *(MBB->pred_end()-1);
|
|
95
|
1361 Pred->ReplaceUsesOfBlockWith(MBB, &*FallThrough);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1362 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1363 // If MBB was the target of a jump table, update jump tables to go to the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1364 // fallthrough instead.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1365 if (MachineJumpTableInfo *MJTI = MF.getJumpTableInfo())
|
|
95
|
1366 MJTI->ReplaceMBBInJumpTables(MBB, &*FallThrough);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1367 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1368 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1369 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1370 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1371
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1372 // Check to see if we can simplify the terminator of the block before this
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1373 // one.
|
|
77
|
1374 MachineBasicBlock &PrevBB = *std::prev(MachineFunction::iterator(MBB));
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1375
|
|
77
|
1376 MachineBasicBlock *PriorTBB = nullptr, *PriorFBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1377 SmallVector<MachineOperand, 4> PriorCond;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1378 bool PriorUnAnalyzable =
|
|
120
|
1379 TII->analyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, true);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1380 if (!PriorUnAnalyzable) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1381 // If the CFG for the prior block has extra edges, remove them.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1382 MadeChange |= PrevBB.CorrectExtraCFGEdges(PriorTBB, PriorFBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1383 !PriorCond.empty());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1384
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1385 // If the previous branch is conditional and both conditions go to the same
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1386 // destination, remove the branch, replacing it with an unconditional one or
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1387 // a fall-through.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1388 if (PriorTBB && PriorTBB == PriorFBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1389 DebugLoc dl = getBranchDebugLoc(PrevBB);
|
|
120
|
1390 TII->removeBranch(PrevBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1391 PriorCond.clear();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1392 if (PriorTBB != MBB)
|
|
120
|
1393 TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1394 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1395 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1396 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1397 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1398
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1399 // If the previous block unconditionally falls through to this block and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1400 // this block has no other predecessors, move the contents of this block
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1401 // into the prior block. This doesn't usually happen when SimplifyCFG
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1402 // has been used, but it can happen if tail merging splits a fall-through
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1403 // predecessor of a block.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1404 // This has to check PrevBB->succ_size() because EH edges are ignored by
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1405 // AnalyzeBranch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1406 if (PriorCond.empty() && !PriorTBB && MBB->pred_size() == 1 &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1407 PrevBB.succ_size() == 1 &&
|
|
95
|
1408 !MBB->hasAddressTaken() && !MBB->isEHPad()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1409 DEBUG(dbgs() << "\nMerging into block: " << PrevBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1410 << "From MBB: " << *MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1411 // Remove redundant DBG_VALUEs first.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1412 if (PrevBB.begin() != PrevBB.end()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1413 MachineBasicBlock::iterator PrevBBIter = PrevBB.end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1414 --PrevBBIter;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1415 MachineBasicBlock::iterator MBBIter = MBB->begin();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1416 // Check if DBG_VALUE at the end of PrevBB is identical to the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1417 // DBG_VALUE at the beginning of MBB.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1418 while (PrevBBIter != PrevBB.begin() && MBBIter != MBB->end()
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1419 && PrevBBIter->isDebugValue() && MBBIter->isDebugValue()) {
|
|
120
|
1420 if (!MBBIter->isIdenticalTo(*PrevBBIter))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1421 break;
|
|
120
|
1422 MachineInstr &DuplicateDbg = *MBBIter;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1423 ++MBBIter; -- PrevBBIter;
|
|
120
|
1424 DuplicateDbg.eraseFromParent();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1425 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1426 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1427 PrevBB.splice(PrevBB.end(), MBB, MBB->begin(), MBB->end());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1428 PrevBB.removeSuccessor(PrevBB.succ_begin());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1429 assert(PrevBB.succ_empty());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1430 PrevBB.transferSuccessors(MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1431 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1432 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1433 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1434
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1435 // If the previous branch *only* branches to *this* block (conditional or
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1436 // not) remove the branch.
|
|
77
|
1437 if (PriorTBB == MBB && !PriorFBB) {
|
|
120
|
1438 TII->removeBranch(PrevBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1439 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1440 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1441 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1442 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1443
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1444 // If the prior block branches somewhere else on the condition and here if
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1445 // the condition is false, remove the uncond second branch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1446 if (PriorFBB == MBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1447 DebugLoc dl = getBranchDebugLoc(PrevBB);
|
|
120
|
1448 TII->removeBranch(PrevBB);
|
|
|
1449 TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1450 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1451 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1452 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1453 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1454
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1455 // If the prior block branches here on true and somewhere else on false, and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1456 // if the branch condition is reversible, reverse the branch to create a
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1457 // fall-through.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1458 if (PriorTBB == MBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1459 SmallVector<MachineOperand, 4> NewPriorCond(PriorCond);
|
|
120
|
1460 if (!TII->reverseBranchCondition(NewPriorCond)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1461 DebugLoc dl = getBranchDebugLoc(PrevBB);
|
|
120
|
1462 TII->removeBranch(PrevBB);
|
|
|
1463 TII->insertBranch(PrevBB, PriorFBB, nullptr, NewPriorCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1464 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1465 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1466 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1467 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1468 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1469
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1470 // If this block has no successors (e.g. it is a return block or ends with
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1471 // a call to a no-return function like abort or __cxa_throw) and if the pred
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1472 // falls through into this block, and if it would otherwise fall through
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1473 // into the block after this, move this block to the end of the function.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1474 //
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1475 // We consider it more likely that execution will stay in the function (e.g.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1476 // due to loops) than it is to exit it. This asserts in loops etc, moving
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1477 // the assert condition out of the loop body.
|
|
77
|
1478 if (MBB->succ_empty() && !PriorCond.empty() && !PriorFBB &&
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1479 MachineFunction::iterator(PriorTBB) == FallThrough &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1480 !MBB->canFallThrough()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1481 bool DoTransform = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1482
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1483 // We have to be careful that the succs of PredBB aren't both no-successor
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1484 // blocks. If neither have successors and if PredBB is the second from
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1485 // last block in the function, we'd just keep swapping the two blocks for
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1486 // last. Only do the swap if one is clearly better to fall through than
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1487 // the other.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1488 if (FallThrough == --MF.end() &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1489 !IsBetterFallthrough(PriorTBB, MBB))
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1490 DoTransform = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1491
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1492 if (DoTransform) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1493 // Reverse the branch so we will fall through on the previous true cond.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1494 SmallVector<MachineOperand, 4> NewPriorCond(PriorCond);
|
|
120
|
1495 if (!TII->reverseBranchCondition(NewPriorCond)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1496 DEBUG(dbgs() << "\nMoving MBB: " << *MBB
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1497 << "To make fallthrough to: " << *PriorTBB << "\n");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1498
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1499 DebugLoc dl = getBranchDebugLoc(PrevBB);
|
|
120
|
1500 TII->removeBranch(PrevBB);
|
|
|
1501 TII->insertBranch(PrevBB, MBB, nullptr, NewPriorCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1502
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1503 // Move this block to the end of the function.
|
|
95
|
1504 MBB->moveAfter(&MF.back());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1505 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1506 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1507 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1508 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1509 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1510 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1511 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1512
|
|
120
|
1513 if (!IsEmptyBlock(MBB) && MBB->pred_size() == 1 &&
|
|
134
|
1514 MF.getFunction().optForSize()) {
|
|
120
|
1515 // Changing "Jcc foo; foo: jmp bar;" into "Jcc bar;" might change the branch
|
|
|
1516 // direction, thereby defeating careful block placement and regressing
|
|
|
1517 // performance. Therefore, only consider this for optsize functions.
|
|
|
1518 MachineInstr &TailCall = *MBB->getFirstNonDebugInstr();
|
|
|
1519 if (TII->isUnconditionalTailCall(TailCall)) {
|
|
|
1520 MachineBasicBlock *Pred = *MBB->pred_begin();
|
|
|
1521 MachineBasicBlock *PredTBB = nullptr, *PredFBB = nullptr;
|
|
|
1522 SmallVector<MachineOperand, 4> PredCond;
|
|
|
1523 bool PredAnalyzable =
|
|
|
1524 !TII->analyzeBranch(*Pred, PredTBB, PredFBB, PredCond, true);
|
|
|
1525
|
|
121
|
1526 if (PredAnalyzable && !PredCond.empty() && PredTBB == MBB &&
|
|
|
1527 PredTBB != PredFBB) {
|
|
120
|
1528 // The predecessor has a conditional branch to this block which consists
|
|
|
1529 // of only a tail call. Try to fold the tail call into the conditional
|
|
|
1530 // branch.
|
|
|
1531 if (TII->canMakeTailCallConditional(PredCond, TailCall)) {
|
|
|
1532 // TODO: It would be nice if analyzeBranch() could provide a pointer
|
|
121
|
1533 // to the branch instruction so replaceBranchWithTailCall() doesn't
|
|
120
|
1534 // have to search for it.
|
|
|
1535 TII->replaceBranchWithTailCall(*Pred, PredCond, TailCall);
|
|
|
1536 ++NumTailCalls;
|
|
|
1537 Pred->removeSuccessor(MBB);
|
|
|
1538 MadeChange = true;
|
|
|
1539 return MadeChange;
|
|
|
1540 }
|
|
|
1541 }
|
|
|
1542 // If the predecessor is falling through to this block, we could reverse
|
|
|
1543 // the branch condition and fold the tail call into that. However, after
|
|
|
1544 // that we might have to re-arrange the CFG to fall through to the other
|
|
|
1545 // block and there is a high risk of regressing code size rather than
|
|
|
1546 // improving it.
|
|
|
1547 }
|
|
|
1548 }
|
|
|
1549
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1550 // Analyze the branch in the current block.
|
|
77
|
1551 MachineBasicBlock *CurTBB = nullptr, *CurFBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1552 SmallVector<MachineOperand, 4> CurCond;
|
|
120
|
1553 bool CurUnAnalyzable =
|
|
|
1554 TII->analyzeBranch(*MBB, CurTBB, CurFBB, CurCond, true);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1555 if (!CurUnAnalyzable) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1556 // If the CFG for the prior block has extra edges, remove them.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1557 MadeChange |= MBB->CorrectExtraCFGEdges(CurTBB, CurFBB, !CurCond.empty());
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1558
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1559 // If this is a two-way branch, and the FBB branches to this block, reverse
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1560 // the condition so the single-basic-block loop is faster. Instead of:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1561 // Loop: xxx; jcc Out; jmp Loop
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1562 // we want:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1563 // Loop: xxx; jncc Loop; jmp Out
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1564 if (CurTBB && CurFBB && CurFBB == MBB && CurTBB != MBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1565 SmallVector<MachineOperand, 4> NewCond(CurCond);
|
|
120
|
1566 if (!TII->reverseBranchCondition(NewCond)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1567 DebugLoc dl = getBranchDebugLoc(*MBB);
|
|
120
|
1568 TII->removeBranch(*MBB);
|
|
|
1569 TII->insertBranch(*MBB, CurFBB, CurTBB, NewCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1570 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1571 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1572 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1573 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1574 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1575
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1576 // If this branch is the only thing in its block, see if we can forward
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1577 // other blocks across it.
|
|
77
|
1578 if (CurTBB && CurCond.empty() && !CurFBB &&
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1579 IsBranchOnlyBlock(MBB) && CurTBB != MBB &&
|
|
100
|
1580 !MBB->hasAddressTaken() && !MBB->isEHPad()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1581 DebugLoc dl = getBranchDebugLoc(*MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1582 // This block may contain just an unconditional branch. Because there can
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1583 // be 'non-branch terminators' in the block, try removing the branch and
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1584 // then seeing if the block is empty.
|
|
120
|
1585 TII->removeBranch(*MBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1586 // If the only things remaining in the block are debug info, remove these
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1587 // as well, so this will behave the same as an empty block in non-debug
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1588 // mode.
|
|
95
|
1589 if (IsEmptyBlock(MBB)) {
|
|
|
1590 // Make the block empty, losing the debug info (we could probably
|
|
|
1591 // improve this in some cases.)
|
|
|
1592 MBB->erase(MBB->begin(), MBB->end());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1593 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1594 // If this block is just an unconditional branch to CurTBB, we can
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1595 // usually completely eliminate the block. The only case we cannot
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1596 // completely eliminate the block is when the block before this one
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1597 // falls through into MBB and we can't understand the prior block's branch
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1598 // condition.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1599 if (MBB->empty()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1600 bool PredHasNoFallThrough = !PrevBB.canFallThrough();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1601 if (PredHasNoFallThrough || !PriorUnAnalyzable ||
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1602 !PrevBB.isSuccessor(MBB)) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1603 // If the prior block falls through into us, turn it into an
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1604 // explicit branch to us to make updates simpler.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1605 if (!PredHasNoFallThrough && PrevBB.isSuccessor(MBB) &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1606 PriorTBB != MBB && PriorFBB != MBB) {
|
|
77
|
1607 if (!PriorTBB) {
|
|
|
1608 assert(PriorCond.empty() && !PriorFBB &&
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1609 "Bad branch analysis");
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1610 PriorTBB = MBB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1611 } else {
|
|
77
|
1612 assert(!PriorFBB && "Machine CFG out of date!");
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1613 PriorFBB = MBB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1614 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1615 DebugLoc pdl = getBranchDebugLoc(PrevBB);
|
|
120
|
1616 TII->removeBranch(PrevBB);
|
|
|
1617 TII->insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1618 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1619
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1620 // Iterate through all the predecessors, revectoring each in-turn.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1621 size_t PI = 0;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1622 bool DidChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1623 bool HasBranchToSelf = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1624 while(PI != MBB->pred_size()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1625 MachineBasicBlock *PMBB = *(MBB->pred_begin() + PI);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1626 if (PMBB == MBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1627 // If this block has an uncond branch to itself, leave it.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1628 ++PI;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1629 HasBranchToSelf = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1630 } else {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1631 DidChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1632 PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1633 // If this change resulted in PMBB ending in a conditional
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1634 // branch where both conditions go to the same destination,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1635 // change this to an unconditional branch (and fix the CFG).
|
|
77
|
1636 MachineBasicBlock *NewCurTBB = nullptr, *NewCurFBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1637 SmallVector<MachineOperand, 4> NewCurCond;
|
|
120
|
1638 bool NewCurUnAnalyzable = TII->analyzeBranch(
|
|
|
1639 *PMBB, NewCurTBB, NewCurFBB, NewCurCond, true);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1640 if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1641 DebugLoc pdl = getBranchDebugLoc(*PMBB);
|
|
120
|
1642 TII->removeBranch(*PMBB);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1643 NewCurCond.clear();
|
|
120
|
1644 TII->insertBranch(*PMBB, NewCurTBB, nullptr, NewCurCond, pdl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1645 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1646 ++NumBranchOpts;
|
|
77
|
1647 PMBB->CorrectExtraCFGEdges(NewCurTBB, nullptr, false);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1648 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1649 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1650 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1651
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1652 // Change any jumptables to go to the new MBB.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1653 if (MachineJumpTableInfo *MJTI = MF.getJumpTableInfo())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1654 MJTI->ReplaceMBBInJumpTables(MBB, CurTBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1655 if (DidChange) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1656 ++NumBranchOpts;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1657 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1658 if (!HasBranchToSelf) return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1659 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1660 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1661 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1662
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1663 // Add the branch back if the block is more than just an uncond branch.
|
|
120
|
1664 TII->insertBranch(*MBB, CurTBB, nullptr, CurCond, dl);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1665 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1666 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1667
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1668 // If the prior block doesn't fall through into this block, and if this
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1669 // block doesn't fall through into some other block, see if we can find a
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1670 // place to move this block where a fall-through will happen.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1671 if (!PrevBB.canFallThrough()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1672 // Now we know that there was no fall-through into this block, check to
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1673 // see if it has a fall-through into its successor.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1674 bool CurFallsThru = MBB->canFallThrough();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1675
|
|
95
|
1676 if (!MBB->isEHPad()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1677 // Check all the predecessors of this block. If one of them has no fall
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1678 // throughs, move this block right after it.
|
|
95
|
1679 for (MachineBasicBlock *PredBB : MBB->predecessors()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1680 // Analyze the branch at the end of the pred.
|
|
77
|
1681 MachineBasicBlock *PredTBB = nullptr, *PredFBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1682 SmallVector<MachineOperand, 4> PredCond;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1683 if (PredBB != MBB && !PredBB->canFallThrough() &&
|
|
120
|
1684 !TII->analyzeBranch(*PredBB, PredTBB, PredFBB, PredCond, true) &&
|
|
|
1685 (!CurFallsThru || !CurTBB || !CurFBB) &&
|
|
|
1686 (!CurFallsThru || MBB->getNumber() >= PredBB->getNumber())) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1687 // If the current block doesn't fall through, just move it.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1688 // If the current block can fall through and does not end with a
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1689 // conditional branch, we need to append an unconditional jump to
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1690 // the (current) next block. To avoid a possible compile-time
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1691 // infinite loop, move blocks only backward in this case.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1692 // Also, if there are already 2 branches here, we cannot add a third;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1693 // this means we have the case
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1694 // Bcc next
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1695 // B elsewhere
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1696 // next:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1697 if (CurFallsThru) {
|
|
95
|
1698 MachineBasicBlock *NextBB = &*std::next(MBB->getIterator());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1699 CurCond.clear();
|
|
120
|
1700 TII->insertBranch(*MBB, NextBB, nullptr, CurCond, DebugLoc());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1701 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1702 MBB->moveAfter(PredBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1703 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1704 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1705 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1706 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1707 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1708
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1709 if (!CurFallsThru) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1710 // Check all successors to see if we can move this block before it.
|
|
95
|
1711 for (MachineBasicBlock *SuccBB : MBB->successors()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1712 // Analyze the branch at the end of the block before the succ.
|
|
95
|
1713 MachineFunction::iterator SuccPrev = --SuccBB->getIterator();
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1714
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1715 // If this block doesn't already fall-through to that successor, and if
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1716 // the succ doesn't already have a block that can fall through into it,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1717 // and if the successor isn't an EH destination, we can arrange for the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1718 // fallthrough to happen.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1719 if (SuccBB != MBB && &*SuccPrev != MBB &&
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1720 !SuccPrev->canFallThrough() && !CurUnAnalyzable &&
|
|
95
|
1721 !SuccBB->isEHPad()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1722 MBB->moveBefore(SuccBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1723 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1724 goto ReoptimizeBlock;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1725 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1726 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1727
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1728 // Okay, there is no really great place to put this block. If, however,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1729 // the block before this one would be a fall-through if this block were
|
|
121
|
1730 // removed, move this block to the end of the function. There is no real
|
|
|
1731 // advantage in "falling through" to an EH block, so we don't want to
|
|
|
1732 // perform this transformation for that case.
|
|
|
1733 //
|
|
|
1734 // Also, Windows EH introduced the possibility of an arbitrary number of
|
|
|
1735 // successors to a given block. The analyzeBranch call does not consider
|
|
|
1736 // exception handling and so we can get in a state where a block
|
|
|
1737 // containing a call is followed by multiple EH blocks that would be
|
|
|
1738 // rotated infinitely at the end of the function if the transformation
|
|
|
1739 // below were performed for EH "FallThrough" blocks. Therefore, even if
|
|
|
1740 // that appears not to be happening anymore, we should assume that it is
|
|
|
1741 // possible and not remove the "!FallThrough()->isEHPad" condition below.
|
|
77
|
1742 MachineBasicBlock *PrevTBB = nullptr, *PrevFBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1743 SmallVector<MachineOperand, 4> PrevCond;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1744 if (FallThrough != MF.end() &&
|
|
121
|
1745 !FallThrough->isEHPad() &&
|
|
120
|
1746 !TII->analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond, true) &&
|
|
95
|
1747 PrevBB.isSuccessor(&*FallThrough)) {
|
|
|
1748 MBB->moveAfter(&MF.back());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1749 MadeChange = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1750 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1751 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1752 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1753 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1754
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1755 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1756 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1757
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1758 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1759 // Hoist Common Code
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1760 //===----------------------------------------------------------------------===//
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1761
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1762 bool BranchFolder::HoistCommonCode(MachineFunction &MF) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1763 bool MadeChange = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1764 for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ) {
|
|
95
|
1765 MachineBasicBlock *MBB = &*I++;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1766 MadeChange |= HoistCommonCodeInSuccs(MBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1767 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1768
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1769 return MadeChange;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1770 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1771
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1772 /// findFalseBlock - BB has a fallthrough. Find its 'false' successor given
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1773 /// its 'true' successor.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1774 static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1775 MachineBasicBlock *TrueBB) {
|
|
95
|
1776 for (MachineBasicBlock *SuccBB : BB->successors())
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1777 if (SuccBB != TrueBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1778 return SuccBB;
|
|
95
|
1779 return nullptr;
|
|
|
1780 }
|
|
|
1781
|
|
|
1782 template <class Container>
|
|
|
1783 static void addRegAndItsAliases(unsigned Reg, const TargetRegisterInfo *TRI,
|
|
|
1784 Container &Set) {
|
|
|
1785 if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
|
|
|
1786 for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
|
|
|
1787 Set.insert(*AI);
|
|
|
1788 } else {
|
|
|
1789 Set.insert(Reg);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1790 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1791 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1792
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1793 /// findHoistingInsertPosAndDeps - Find the location to move common instructions
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1794 /// in successors to. The location is usually just before the terminator,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1795 /// however if the terminator is a conditional branch and its previous
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1796 /// instruction is the flag setting instruction, the previous instruction is
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1797 /// the preferred location. This function also gathers uses and defs of the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1798 /// instructions from the insertion point to the end of the block. The data is
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1799 /// used by HoistCommonCodeInSuccs to ensure safety.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1800 static
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1801 MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1802 const TargetInstrInfo *TII,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1803 const TargetRegisterInfo *TRI,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1804 SmallSet<unsigned,4> &Uses,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1805 SmallSet<unsigned,4> &Defs) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1806 MachineBasicBlock::iterator Loc = MBB->getFirstTerminator();
|
|
120
|
1807 if (!TII->isUnpredicatedTerminator(*Loc))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1808 return MBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1809
|
|
95
|
1810 for (const MachineOperand &MO : Loc->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1811 if (!MO.isReg())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1812 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1813 unsigned Reg = MO.getReg();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1814 if (!Reg)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1815 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1816 if (MO.isUse()) {
|
|
95
|
1817 addRegAndItsAliases(Reg, TRI, Uses);
|
|
77
|
1818 } else {
|
|
|
1819 if (!MO.isDead())
|
|
|
1820 // Don't try to hoist code in the rare case the terminator defines a
|
|
|
1821 // register that is later used.
|
|
|
1822 return MBB->end();
|
|
|
1823
|
|
|
1824 // If the terminator defines a register, make sure we don't hoist
|
|
|
1825 // the instruction whose def might be clobbered by the terminator.
|
|
95
|
1826 addRegAndItsAliases(Reg, TRI, Defs);
|
|
77
|
1827 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1828 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1829
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1830 if (Uses.empty())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1831 return Loc;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1832 if (Loc == MBB->begin())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1833 return MBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1834
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1835 // The terminator is probably a conditional branch, try not to separate the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1836 // branch from condition setting instruction.
|
|
121
|
1837 MachineBasicBlock::iterator PI =
|
|
|
1838 skipDebugInstructionsBackward(std::prev(Loc), MBB->begin());
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1839
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1840 bool IsDef = false;
|
|
95
|
1841 for (const MachineOperand &MO : PI->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1842 // If PI has a regmask operand, it is probably a call. Separate away.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1843 if (MO.isRegMask())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1844 return Loc;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1845 if (!MO.isReg() || MO.isUse())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1846 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1847 unsigned Reg = MO.getReg();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1848 if (!Reg)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1849 continue;
|
|
95
|
1850 if (Uses.count(Reg)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1851 IsDef = true;
|
|
95
|
1852 break;
|
|
|
1853 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1854 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1855 if (!IsDef)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1856 // The condition setting instruction is not just before the conditional
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1857 // branch.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1858 return Loc;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1859
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1860 // Be conservative, don't insert instruction above something that may have
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1861 // side-effects. And since it's potentially bad to separate flag setting
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1862 // instruction from the conditional branch, just abort the optimization
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1863 // completely.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1864 // Also avoid moving code above predicated instruction since it's hard to
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1865 // reason about register liveness with predicated instruction.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1866 bool DontMoveAcrossStore = true;
|
|
120
|
1867 if (!PI->isSafeToMove(nullptr, DontMoveAcrossStore) || TII->isPredicated(*PI))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1868 return MBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1869
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1870 // Find out what registers are live. Note this routine is ignoring other live
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1871 // registers which are only used by instructions in successor blocks.
|
|
95
|
1872 for (const MachineOperand &MO : PI->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1873 if (!MO.isReg())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1874 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1875 unsigned Reg = MO.getReg();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1876 if (!Reg)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1877 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1878 if (MO.isUse()) {
|
|
95
|
1879 addRegAndItsAliases(Reg, TRI, Uses);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1880 } else {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1881 if (Uses.erase(Reg)) {
|
|
95
|
1882 if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
|
|
|
1883 for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
|
|
|
1884 Uses.erase(*SubRegs); // Use sub-registers to be conservative
|
|
|
1885 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1886 }
|
|
95
|
1887 addRegAndItsAliases(Reg, TRI, Defs);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1888 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1889 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1890
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1891 return PI;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1892 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1893
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1894 bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
|
|
77
|
1895 MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1896 SmallVector<MachineOperand, 4> Cond;
|
|
120
|
1897 if (TII->analyzeBranch(*MBB, TBB, FBB, Cond, true) || !TBB || Cond.empty())
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1898 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1899
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1900 if (!FBB) FBB = findFalseBlock(MBB, TBB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1901 if (!FBB)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1902 // Malformed bcc? True and false blocks are the same?
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1903 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1904
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1905 // Restrict the optimization to cases where MBB is the only predecessor,
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1906 // it is an obvious win.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1907 if (TBB->pred_size() > 1 || FBB->pred_size() > 1)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1908 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1909
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1910 // Find a suitable position to hoist the common instructions to. Also figure
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1911 // out which registers are used or defined by instructions from the insertion
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1912 // point to the end of the block.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1913 SmallSet<unsigned, 4> Uses, Defs;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1914 MachineBasicBlock::iterator Loc =
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1915 findHoistingInsertPosAndDeps(MBB, TII, TRI, Uses, Defs);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1916 if (Loc == MBB->end())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1917 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1918
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1919 bool HasDups = false;
|
|
121
|
1920 SmallVector<unsigned, 4> LocalDefs, LocalKills;
|
|
|
1921 SmallSet<unsigned, 4> ActiveDefsSet, AllDefsSet;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1922 MachineBasicBlock::iterator TIB = TBB->begin();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1923 MachineBasicBlock::iterator FIB = FBB->begin();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1924 MachineBasicBlock::iterator TIE = TBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1925 MachineBasicBlock::iterator FIE = FBB->end();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1926 while (TIB != TIE && FIB != FIE) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1927 // Skip dbg_value instructions. These do not count.
|
|
121
|
1928 TIB = skipDebugInstructionsForward(TIB, TIE);
|
|
|
1929 FIB = skipDebugInstructionsForward(FIB, FIE);
|
|
|
1930 if (TIB == TIE || FIB == FIE)
|
|
|
1931 break;
|
|
|
1932
|
|
120
|
1933 if (!TIB->isIdenticalTo(*FIB, MachineInstr::CheckKillDead))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1934 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1935
|
|
120
|
1936 if (TII->isPredicated(*TIB))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1937 // Hard to reason about register liveness with predicated instruction.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1938 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1939
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1940 bool IsSafe = true;
|
|
95
|
1941 for (MachineOperand &MO : TIB->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1942 // Don't attempt to hoist instructions with register masks.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1943 if (MO.isRegMask()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1944 IsSafe = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1945 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1946 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1947 if (!MO.isReg())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1948 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1949 unsigned Reg = MO.getReg();
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1950 if (!Reg)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1951 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1952 if (MO.isDef()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1953 if (Uses.count(Reg)) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1954 // Avoid clobbering a register that's used by the instruction at
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1955 // the point of insertion.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1956 IsSafe = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1957 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1958 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1959
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1960 if (Defs.count(Reg) && !MO.isDead()) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1961 // Don't hoist the instruction if the def would be clobber by the
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1962 // instruction at the point insertion. FIXME: This is overly
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1963 // conservative. It should be possible to hoist the instructions
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1964 // in BB2 in the following example:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1965 // BB1:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1966 // r1, eflag = op1 r2, r3
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1967 // brcc eflag
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1968 //
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1969 // BB2:
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1970 // r1 = op2, ...
|
|
134
|
1971 // = op3, killed r1
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1972 IsSafe = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1973 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1974 }
|
|
121
|
1975 } else if (!ActiveDefsSet.count(Reg)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1976 if (Defs.count(Reg)) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1977 // Use is defined by the instruction at the point of insertion.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1978 IsSafe = false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1979 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1980 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1981
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1982 if (MO.isKill() && Uses.count(Reg))
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1983 // Kills a register that's read by the instruction at the point of
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1984 // insertion. Remove the kill marker.
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1985 MO.setIsKill(false);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1986 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1987 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1988 if (!IsSafe)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1989 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1990
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1991 bool DontMoveAcrossStore = true;
|
|
95
|
1992 if (!TIB->isSafeToMove(nullptr, DontMoveAcrossStore))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1993 break;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1994
|
|
121
|
1995 // Remove kills from ActiveDefsSet, these registers had short live ranges.
|
|
95
|
1996 for (const MachineOperand &MO : TIB->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1997 if (!MO.isReg() || !MO.isUse() || !MO.isKill())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1998 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
1999 unsigned Reg = MO.getReg();
|
|
121
|
2000 if (!Reg)
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2001 continue;
|
|
121
|
2002 if (!AllDefsSet.count(Reg)) {
|
|
|
2003 LocalKills.push_back(Reg);
|
|
|
2004 continue;
|
|
|
2005 }
|
|
95
|
2006 if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
|
|
|
2007 for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
|
|
121
|
2008 ActiveDefsSet.erase(*AI);
|
|
95
|
2009 } else {
|
|
121
|
2010 ActiveDefsSet.erase(Reg);
|
|
95
|
2011 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2012 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2013
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2014 // Track local defs so we can update liveins.
|
|
95
|
2015 for (const MachineOperand &MO : TIB->operands()) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2016 if (!MO.isReg() || !MO.isDef() || MO.isDead())
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2017 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2018 unsigned Reg = MO.getReg();
|
|
120
|
2019 if (!Reg || TargetRegisterInfo::isVirtualRegister(Reg))
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2020 continue;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2021 LocalDefs.push_back(Reg);
|
|
121
|
2022 addRegAndItsAliases(Reg, TRI, ActiveDefsSet);
|
|
|
2023 addRegAndItsAliases(Reg, TRI, AllDefsSet);
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2024 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2025
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2026 HasDups = true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2027 ++TIB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2028 ++FIB;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2029 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2030
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2031 if (!HasDups)
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2032 return false;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2033
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2034 MBB->splice(Loc, TBB, TBB->begin(), TIB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2035 FBB->erase(FBB->begin(), FIB);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2036
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2037 // Update livein's.
|
|
121
|
2038 bool ChangedLiveIns = false;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2039 for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2040 unsigned Def = LocalDefs[i];
|
|
121
|
2041 if (ActiveDefsSet.count(Def)) {
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2042 TBB->addLiveIn(Def);
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2043 FBB->addLiveIn(Def);
|
|
121
|
2044 ChangedLiveIns = true;
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2045 }
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2046 }
|
|
121
|
2047 for (unsigned K : LocalKills) {
|
|
|
2048 TBB->removeLiveIn(K);
|
|
|
2049 FBB->removeLiveIn(K);
|
|
|
2050 ChangedLiveIns = true;
|
|
|
2051 }
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2052
|
|
121
|
2053 if (ChangedLiveIns) {
|
|
120
|
2054 TBB->sortUniqueLiveIns();
|
|
|
2055 FBB->sortUniqueLiveIns();
|
|
|
2056 }
|
|
|
2057
|
0
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2058 ++NumHoist;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2059 return true;
|
Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
parents:
diff
changeset
|
2060 }
|
