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Revert patch which broke some IfConversion tests.

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llvm-svn: 135738
This commit is contained in:
Jakub Staszak 2011-07-22 00:55:15 +00:00
parent eca22965a3
commit 50b63cc04e
1 changed files with 28 additions and 9 deletions
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37
lib/CodeGen/IfConversion.cpp
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@ -16,13 +16,14 @@
#include "llvm/Function.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/BranchProbability.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
@ -153,8 +154,7 @@ namespace {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
const InstrItineraryData *InstrItins;
const MachineBranchProbabilityInfo *MBPI;
const MachineLoopInfo *MLI;
bool MadeChange;
int FnNum;
public:
@ -162,9 +162,9 @@ namespace {
IfConverter() : MachineFunctionPass(ID), FnNum(-1) {
initializeIfConverterPass(*PassRegistry::getPassRegistry());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineBranchProbabilityInfo>();
AU.addRequired<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
@ -252,7 +252,7 @@ namespace {
}
INITIALIZE_PASS_BEGIN(IfConverter, "if-converter", "If Converter", false, false)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
INITIALIZE_PASS_END(IfConverter, "if-converter", "If Converter", false, false)
FunctionPass *llvm::createIfConverterPass() { return new IfConverter(); }
@ -261,7 +261,7 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
TLI = MF.getTarget().getTargetLowering();
TII = MF.getTarget().getInstrInfo();
TRI = MF.getTarget().getRegisterInfo();
MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
MLI = &getAnalysis<MachineLoopInfo>();
InstrItins = MF.getTarget().getInstrItineraryData();
if (!TII) return false;
@ -790,9 +790,28 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
bool TNeedSub = TrueBBI.Predicate.size() > 0;
bool FNeedSub = FalseBBI.Predicate.size() > 0;
bool Enqueued = false;
// Try to predict the branch, using loop info to guide us.
// General heuristics are:
// - backedge -> 90% taken
// - early exit -> 20% taken
// - branch predictor confidence -> 90%
BranchProbability Prediction(5, 10);
MachineLoop *Loop = MLI->getLoopFor(BB);
if (Loop) {
if (TrueBBI.BB == Loop->getHeader())
Prediction = BranchProbability(9, 10);
else if (FalseBBI.BB == Loop->getHeader())
Prediction = BranchProbability(1, 10);
BranchProbability Prediction = MBPI->getEdgeProbability(BB, TrueBBI.BB);
MachineLoop *TrueLoop = MLI->getLoopFor(TrueBBI.BB);
MachineLoop *FalseLoop = MLI->getLoopFor(FalseBBI.BB);
if (!TrueLoop || TrueLoop->getParentLoop() == Loop)
Prediction = BranchProbability(2, 10);
else if (!FalseLoop || FalseLoop->getParentLoop() == Loop)
Prediction = BranchProbability(8, 10);
}
if (CanRevCond && ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2) &&
MeetIfcvtSizeLimit(*TrueBBI.BB, (TrueBBI.NonPredSize - (Dups + Dups2) +
TrueBBI.ExtraCost), TrueBBI.ExtraCost2,