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Revert "Move function to obtain branch weights into the BranchInst class. NFC."

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This reverts commit r223784 and copies the 'ExtractBranchMetadata' to CodeGenPrepare.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223795 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Juergen Ributzka
2014-12-09 17:32:12 +00:00
parent 574ca2ad28
commit f3ac16dcb4
4 changed files with 49 additions and 32 deletions
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25
lib/CodeGen/CodeGenPrepare.cpp
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@ -3800,6 +3800,27 @@ bool CodeGenPrepare::sinkAndCmp(Function &F) {
return MadeChange;
}
/// \brief Retrieve the probabilities of a conditional branch. Returns true on
/// success, or returns false if no or invalid metadata was found.
static bool extractBranchMetadata(BranchInst *BI,
uint64_t &ProbTrue, uint64_t &ProbFalse) {
assert(BI->isConditional() &&
"Looking for probabilities on unconditional branch?");
auto *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
if (!ProfileData || ProfileData->getNumOperands() != 3)
return false;
const auto *CITrue = dyn_cast<ConstantInt>(ProfileData->getOperand(1));
const auto *CIFalse = dyn_cast<ConstantInt>(ProfileData->getOperand(2));
if (!CITrue || !CIFalse)
return false;
ProbTrue = CITrue->getValue().getZExtValue();
ProbFalse = CIFalse->getValue().getZExtValue();
return true;
}
/// \brief Scale down both weights to fit into uint32_t.
static void scaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) {
uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse;
@ -3942,7 +3963,7 @@ bool CodeGenPrepare::splitBranchCondition(Function &F) {
// Another choice is to assume TrueProb for BB1 equals to TrueProb for
// TmpBB, but the math is more complicated.
uint64_t TrueWeight, FalseWeight;
if (Br1->getBranchWeights(TrueWeight, FalseWeight)) {
if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
uint64_t NewTrueWeight = TrueWeight;
uint64_t NewFalseWeight = TrueWeight + 2 * FalseWeight;
scaleWeights(NewTrueWeight, NewFalseWeight);
@ -3975,7 +3996,7 @@ bool CodeGenPrepare::splitBranchCondition(Function &F) {
// assumes that
// FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB.
uint64_t TrueWeight, FalseWeight;
if (Br1->getBranchWeights(TrueWeight, FalseWeight)) {
if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
uint64_t NewTrueWeight = 2 * TrueWeight + FalseWeight;
uint64_t NewFalseWeight = FalseWeight;
scaleWeights(NewTrueWeight, NewFalseWeight);