From 937338cf64350a7d05d0c956dc8e8564e959cb7b Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sat, 26 May 2012 13:59:43 +0000 Subject: Add support for branch weight metadata to MDBuilder and use it in various places. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157515 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Support/MDBuilder.h | 23 ++++++++++++++ lib/Transforms/Utils/LowerExpectIntrinsic.cpp | 44 +++++++++++---------------- lib/Transforms/Utils/SimplifyCFG.cpp | 11 +++---- 3 files changed, 46 insertions(+), 32 deletions(-) diff --git a/include/llvm/Support/MDBuilder.h b/include/llvm/Support/MDBuilder.h index 40f028a432..855e58d699 100644 --- a/include/llvm/Support/MDBuilder.h +++ b/include/llvm/Support/MDBuilder.h @@ -49,6 +49,29 @@ namespace llvm { return MDNode::get(Context, Op); } + //===------------------------------------------------------------------===// + // Prof metadata. + //===------------------------------------------------------------------===// + + /// \brief Return metadata containing two branch weights. + MDNode *createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight) { + uint32_t Weights[] = { TrueWeight, FalseWeight }; + return createBranchWeights(Weights); + } + + /// \brief Return metadata containing a number of branch weights. + MDNode *createBranchWeights(ArrayRef Weights) { + assert(Weights.size() >= 2 && "Need at least two branch weights!"); + + SmallVector Vals(Weights.size()+1); + Vals[0] = createString("branch_weights"); + + Type *Int32Ty = Type::getInt32Ty(Context); + for (unsigned i = 0, e = Weights.size(); i != e; ++i) + Vals[i+1] = ConstantInt::get(Int32Ty, Weights[i]); + + return MDNode::get(Context, Vals); + } //===------------------------------------------------------------------===// // Range metadata. diff --git a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp index c70ced18e4..f96581393d 100644 --- a/lib/Transforms/Utils/LowerExpectIntrinsic.cpp +++ b/lib/Transforms/Utils/LowerExpectIntrinsic.cpp @@ -23,6 +23,7 @@ #include "llvm/Transforms/Scalar.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/MDBuilder.h" #include "llvm/ADT/Statistic.h" #include @@ -70,24 +71,18 @@ bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) { if (!ExpectedValue) return false; - LLVMContext &Context = CI->getContext(); - Type *Int32Ty = Type::getInt32Ty(Context); - SwitchInst::CaseIt Case = SI->findCaseValue(ExpectedValue); - std::vector Vec; - unsigned n = SI->getNumCases(); - Vec.resize(n + 1 + 1); // +1 for MDString and +1 for default case - - Vec[0] = MDString::get(Context, "branch_weights"); - Vec[1] = ConstantInt::get(Int32Ty, Case == SI->case_default() ? - LikelyBranchWeight : UnlikelyBranchWeight); - for (unsigned i = 0; i < n; ++i) { - Vec[i + 1 + 1] = ConstantInt::get(Int32Ty, i == Case.getCaseIndex() ? - LikelyBranchWeight : UnlikelyBranchWeight); - } + unsigned n = SI->getNumCases(); // +1 for default case. + std::vector Weights(n + 1); - MDNode *WeightsNode = llvm::MDNode::get(Context, Vec); - SI->setMetadata(LLVMContext::MD_prof, WeightsNode); + Weights[0] = Case == SI->case_default() ? LikelyBranchWeight + : UnlikelyBranchWeight; + for (unsigned i = 0; i != n; ++i) + Weights[i + 1] = i == Case.getCaseIndex() ? LikelyBranchWeight + : UnlikelyBranchWeight; + + SI->setMetadata(LLVMContext::MD_prof, + MDBuilder(CI->getContext()).createBranchWeights(Weights)); SI->setCondition(ArgValue); return true; @@ -120,20 +115,17 @@ bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) { if (!ExpectedValue) return false; - LLVMContext &Context = CI->getContext(); - Type *Int32Ty = Type::getInt32Ty(Context); - bool Likely = ExpectedValue->isOne(); + MDBuilder MDB(CI->getContext()); + MDNode *Node; // If expect value is equal to 1 it means that we are more likely to take // branch 0, in other case more likely is branch 1. - Value *Ops[] = { - MDString::get(Context, "branch_weights"), - ConstantInt::get(Int32Ty, Likely ? LikelyBranchWeight : UnlikelyBranchWeight), - ConstantInt::get(Int32Ty, Likely ? UnlikelyBranchWeight : LikelyBranchWeight) - }; + if (ExpectedValue->isOne()) + Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight); + else + Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight); - MDNode *WeightsNode = MDNode::get(Context, Ops); - BI->setMetadata(LLVMContext::MD_prof, WeightsNode); + BI->setMetadata(LLVMContext::MD_prof, Node); CmpI->setOperand(0, ArgValue); return true; diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 66dd2c954e..9b04ef29f4 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -37,6 +37,7 @@ #include "llvm/Support/ConstantRange.h" #include "llvm/Support/Debug.h" #include "llvm/Support/IRBuilder.h" +#include "llvm/Support/MDBuilder.h" #include "llvm/Support/NoFolder.h" #include "llvm/Support/raw_ostream.h" #include @@ -1740,12 +1741,10 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI) { ProbTrue = ProbTrue.udiv(GCD); ProbFalse = ProbFalse.udiv(GCD); - LLVMContext &Context = BI->getContext(); - Value *Ops[3]; - Ops[0] = BI->getMetadata(LLVMContext::MD_prof)->getOperand(0); - Ops[1] = ConstantInt::get(Context, ProbTrue); - Ops[2] = ConstantInt::get(Context, ProbFalse); - PBI->setMetadata(LLVMContext::MD_prof, MDNode::get(Context, Ops)); + MDBuilder MDB(BI->getContext()); + MDNode *N = MDB.createBranchWeights(ProbTrue.getZExtValue(), + ProbFalse.getZExtValue()); + PBI->setMetadata(LLVMContext::MD_prof, N); } else { PBI->setMetadata(LLVMContext::MD_prof, NULL); } -- cgit v1.2.3