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-rw-r--r--contrib/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp188
1 files changed, 0 insertions, 188 deletions
diff --git a/contrib/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp b/contrib/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
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--- a/contrib/llvm/lib/Transforms/Utils/LowerExpectIntrinsic.cpp
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-//===- LowerExpectIntrinsic.cpp - Lower expect intrinsic ------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass lowers the 'expect' intrinsic to LLVM metadata.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/IR/BasicBlock.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/MDBuilder.h"
-#include "llvm/IR/Metadata.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include <vector>
-
-using namespace llvm;
-
-#define DEBUG_TYPE "lower-expect-intrinsic"
-
-STATISTIC(IfHandled, "Number of 'expect' intrinsic instructions handled");
-
-static cl::opt<uint32_t>
-LikelyBranchWeight("likely-branch-weight", cl::Hidden, cl::init(64),
- cl::desc("Weight of the branch likely to be taken (default = 64)"));
-static cl::opt<uint32_t>
-UnlikelyBranchWeight("unlikely-branch-weight", cl::Hidden, cl::init(4),
- cl::desc("Weight of the branch unlikely to be taken (default = 4)"));
-
-namespace {
-
- class LowerExpectIntrinsic : public FunctionPass {
-
- bool HandleSwitchExpect(SwitchInst *SI);
-
- bool HandleIfExpect(BranchInst *BI);
-
- public:
- static char ID;
- LowerExpectIntrinsic() : FunctionPass(ID) {
- initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override;
- };
-}
-
-
-bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) {
- CallInst *CI = dyn_cast<CallInst>(SI->getCondition());
- if (!CI)
- return false;
-
- Function *Fn = CI->getCalledFunction();
- if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
- return false;
-
- Value *ArgValue = CI->getArgOperand(0);
- ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
- if (!ExpectedValue)
- return false;
-
- SwitchInst::CaseIt Case = SI->findCaseValue(ExpectedValue);
- unsigned n = SI->getNumCases(); // +1 for default case.
- std::vector<uint32_t> Weights(n + 1);
-
- 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;
-}
-
-
-bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) {
- if (BI->isUnconditional())
- return false;
-
- // Handle non-optimized IR code like:
- // %expval = call i64 @llvm.expect.i64(i64 %conv1, i64 1)
- // %tobool = icmp ne i64 %expval, 0
- // br i1 %tobool, label %if.then, label %if.end
- //
- // Or the following simpler case:
- // %expval = call i1 @llvm.expect.i1(i1 %cmp, i1 1)
- // br i1 %expval, label %if.then, label %if.end
-
- CallInst *CI;
-
- ICmpInst *CmpI = dyn_cast<ICmpInst>(BI->getCondition());
- if (!CmpI) {
- CI = dyn_cast<CallInst>(BI->getCondition());
- } else {
- if (CmpI->getPredicate() != CmpInst::ICMP_NE)
- return false;
- CI = dyn_cast<CallInst>(CmpI->getOperand(0));
- }
-
- if (!CI)
- return false;
-
- Function *Fn = CI->getCalledFunction();
- if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
- return false;
-
- Value *ArgValue = CI->getArgOperand(0);
- ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
- if (!ExpectedValue)
- return false;
-
- 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.
- if (ExpectedValue->isOne())
- Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight);
- else
- Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight);
-
- BI->setMetadata(LLVMContext::MD_prof, Node);
-
- if (CmpI)
- CmpI->setOperand(0, ArgValue);
- else
- BI->setCondition(ArgValue);
- return true;
-}
-
-
-bool LowerExpectIntrinsic::runOnFunction(Function &F) {
- for (Function::iterator I = F.begin(), E = F.end(); I != E;) {
- BasicBlock *BB = I++;
-
- // Create "block_weights" metadata.
- if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator())) {
- if (HandleIfExpect(BI))
- IfHandled++;
- } else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
- if (HandleSwitchExpect(SI))
- IfHandled++;
- }
-
- // remove llvm.expect intrinsics.
- for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
- BI != BE; ) {
- CallInst *CI = dyn_cast<CallInst>(BI++);
- if (!CI)
- continue;
-
- Function *Fn = CI->getCalledFunction();
- if (Fn && Fn->getIntrinsicID() == Intrinsic::expect) {
- Value *Exp = CI->getArgOperand(0);
- CI->replaceAllUsesWith(Exp);
- CI->eraseFromParent();
- }
- }
- }
-
- return false;
-}
-
-
-char LowerExpectIntrinsic::ID = 0;
-INITIALIZE_PASS(LowerExpectIntrinsic, "lower-expect", "Lower 'expect' "
- "Intrinsics", false, false)
-
-FunctionPass *llvm::createLowerExpectIntrinsicPass() {
- return new LowerExpectIntrinsic();
-}
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