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

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Make this function available to other parts of LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223784 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Juergen Ributzka 2014-12-09 16:36:06 +00:00
parent b900895384
commit 50f10eb432
3 changed files with 30 additions and 26 deletions
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4
include/llvm/IR/Instructions.h
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@ -2535,6 +2535,10 @@ public:
/// continues to map correctly to each operand.
void swapSuccessors();
/// \brief Retrieve the probabilities of a conditional branch. Returns true on
/// success, or returns false if no or invalid metadata was found.
bool getBranchWeights(uint64_t &TrueWeight, uint64_t &FalseWeight) const;
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Instruction *I) {
return (I->getOpcode() == Instruction::Br);

20
lib/IR/Instructions.cpp
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@ -805,6 +805,26 @@ void BranchInst::swapSuccessors() {
MDNode::get(ProfileData->getContext(), Ops));
}
bool BranchInst::getBranchWeights(uint64_t &TrueWeight,
uint64_t &FalseWeight) const {
if (isUnconditional())
return false;
auto *MD = getMetadata(LLVMContext::MD_prof);
if (!MD || MD->getNumOperands() != 3)
return false;
auto *TrueCI = dyn_cast<ConstantInt>(MD->getOperand(1));
auto *FalseCI = dyn_cast<ConstantInt>(MD->getOperand(2));
if (!TrueCI || !FalseCI)
return false;
TrueWeight = TrueCI->getValue().getZExtValue();
FalseWeight = FalseCI->getValue().getZExtValue();
return true;
}
BasicBlock *BranchInst::getSuccessorV(unsigned idx) const {
return getSuccessor(idx);
}

32
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -2027,24 +2027,6 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
return true;
}
/// ExtractBranchMetadata - Given a conditional BranchInstruction, retrieve the
/// probabilities of the branch taking each edge. Fills in the two APInt
/// parameters and return true, 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?");
MDNode *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
if (!ProfileData || ProfileData->getNumOperands() != 3) return false;
ConstantInt *CITrue = dyn_cast<ConstantInt>(ProfileData->getOperand(1));
ConstantInt *CIFalse = dyn_cast<ConstantInt>(ProfileData->getOperand(2));
if (!CITrue || !CIFalse) return false;
ProbTrue = CITrue->getValue().getZExtValue();
ProbFalse = CIFalse->getValue().getZExtValue();
return true;
}
/// checkCSEInPredecessor - Return true if the given instruction is available
/// in its predecessor block. If yes, the instruction will be removed.
///
@ -2250,10 +2232,10 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL,
PBI->setCondition(NewCond);
uint64_t PredTrueWeight, PredFalseWeight, SuccTrueWeight, SuccFalseWeight;
bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
PredFalseWeight);
bool SuccHasWeights = ExtractBranchMetadata(BI, SuccTrueWeight,
SuccFalseWeight);
bool PredHasWeights =
PBI->getBranchWeights(PredTrueWeight, PredFalseWeight);
bool SuccHasWeights =
BI->getBranchWeights(SuccTrueWeight, SuccFalseWeight);
SmallVector<uint64_t, 8> NewWeights;
if (PBI->getSuccessor(0) == BB) {
@ -2523,10 +2505,8 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
// Update branch weight for PBI.
uint64_t PredTrueWeight, PredFalseWeight, SuccTrueWeight, SuccFalseWeight;
bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
PredFalseWeight);
bool SuccHasWeights = ExtractBranchMetadata(BI, SuccTrueWeight,
SuccFalseWeight);
bool PredHasWeights = PBI->getBranchWeights(PredTrueWeight, PredFalseWeight);
bool SuccHasWeights = BI->getBranchWeights(SuccTrueWeight, SuccFalseWeight);
if (PredHasWeights && SuccHasWeights) {
uint64_t PredCommon = PBIOp ? PredFalseWeight : PredTrueWeight;
uint64_t PredOther = PBIOp ?PredTrueWeight : PredFalseWeight;