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Revert r216862 due to a performance regression

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Reported by Alexey Volkov in PR21115


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218771 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jingyue Wu
2014-10-01 15:22:13 +00:00
parent a2878ec715
commit ccd995ab0c
4 changed files with 28 additions and 59 deletions
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30
lib/CodeGen/MachineSink.cpp
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@ -24,7 +24,6 @@
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
@ -56,9 +55,8 @@ namespace {
class MachineSinking : public MachineFunctionPass {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
MachineRegisterInfo *MRI; // Machine register information
MachineDominatorTree *DT; // Machine dominator tree
MachinePostDominatorTree *PDT; // Machine post dominator tree
MachineRegisterInfo *MRI; // Machine register information
MachineDominatorTree *DT; // Machine dominator tree
MachineLoopInfo *LI;
const MachineBlockFrequencyInfo *MBFI;
AliasAnalysis *AA;
@ -84,10 +82,8 @@ namespace {
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<AliasAnalysis>();
AU.addRequired<MachineDominatorTree>();
AU.addRequired<MachinePostDominatorTree>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
AU.addPreserved<MachinePostDominatorTree>();
AU.addPreserved<MachineLoopInfo>();
if (UseBlockFreqInfo)
AU.addRequired<MachineBlockFrequencyInfo>();
@ -255,7 +251,6 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) {
TRI = TM.getSubtargetImpl()->getRegisterInfo();
MRI = &MF.getRegInfo();
DT = &getAnalysis<MachineDominatorTree>();
PDT = &getAnalysis<MachinePostDominatorTree>();
LI = &getAnalysis<MachineLoopInfo>();
MBFI = UseBlockFreqInfo ? &getAnalysis<MachineBlockFrequencyInfo>() : nullptr;
AA = &getAnalysis<AliasAnalysis>();
@ -474,6 +469,23 @@ static void collectDebugValues(MachineInstr *MI,
}
}
/// isPostDominatedBy - Return true if A is post dominated by B.
static bool isPostDominatedBy(MachineBasicBlock *A, MachineBasicBlock *B) {
// FIXME - Use real post dominator.
if (A->succ_size() != 2)
return false;
MachineBasicBlock::succ_iterator I = A->succ_begin();
if (B == *I)
++I;
MachineBasicBlock *OtherSuccBlock = *I;
if (OtherSuccBlock->succ_size() != 1 ||
*(OtherSuccBlock->succ_begin()) != B)
return false;
return true;
}
/// isProfitableToSinkTo - Return true if it is profitable to sink MI.
bool MachineSinking::isProfitableToSinkTo(unsigned Reg, MachineInstr *MI,
MachineBasicBlock *MBB,
@ -485,8 +497,8 @@ bool MachineSinking::isProfitableToSinkTo(unsigned Reg, MachineInstr *MI,
return false;
// It is profitable if SuccToSinkTo does not post dominate current block.
if (!PDT->dominates(SuccToSinkTo, MBB))
return true;
if (!isPostDominatedBy(MBB, SuccToSinkTo))
return true;
// Check if only use in post dominated block is PHI instruction.
bool NonPHIUse = false;