diff options
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 47 |
1 files changed, 25 insertions, 22 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index c0b0cbe..7a4c685 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -16,6 +16,7 @@ #include "llvm/IntrinsicInst.h" #include "llvm/LLVMContext.h" #include "llvm/Pass.h" +#include "llvm/Analysis/ConstantFolding.h" #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/LazyValueInfo.h" #include "llvm/Analysis/Loads.h" @@ -325,9 +326,10 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ } else if (LVI) { Constant *CI = LVI->getConstantOnEdge(InVal, PN->getIncomingBlock(i), BB); - ConstantInt *CInt = dyn_cast_or_null<ConstantInt>(CI); - if (CInt) - Result.push_back(std::make_pair(CInt, PN->getIncomingBlock(i))); + // LVI returns null is no value could be determined. + if (!CI) continue; + ConstantInt *CInt = dyn_cast<ConstantInt>(CI); + Result.push_back(std::make_pair(CInt, PN->getIncomingBlock(i))); } } return !Result.empty(); @@ -373,10 +375,6 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ } } return !Result.empty(); - - // Try to process a few other binary operator patterns. - } else if (isa<BinaryOperator>(I)) { - } // Handle the NOT form of XOR. @@ -400,12 +398,19 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ // AND or OR of a value with itself is that value. ConstantInt *CI = dyn_cast<ConstantInt>(BO->getOperand(1)); if (CI && (BO->getOpcode() == Instruction::And || - BO->getOpcode() == Instruction::Or)) { + BO->getOpcode() == Instruction::Or)) { SmallVector<std::pair<ConstantInt*, BasicBlock*>, 8> LHSVals; ComputeValueKnownInPredecessors(BO->getOperand(0), BB, LHSVals); - for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) - if (LHSVals[i].first == CI) - Result.push_back(std::make_pair(CI, LHSVals[i].second)); + for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) + if (LHSVals[i].first == 0) { + ConstantInt *Zero = + cast<ConstantInt>(ConstantInt::get(BO->getType(), 0)); + Result.push_back(std::make_pair(Zero, LHSVals[i].second)); + } else if (Constant *Folded = ConstantExpr::get(BO->getOpcode(), + LHSVals[i].first, CI)) { + Result.push_back(std::make_pair(cast<ConstantInt>(Folded), + LHSVals[i].second)); + } return !Result.empty(); } @@ -450,7 +455,7 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ if (LVI && isa<Constant>(Cmp->getOperand(1)) && Cmp->getType()->isIntegerTy()) { if (!isa<Instruction>(Cmp->getOperand(0)) || - cast<Instruction>(Cmp->getOperand(0))->getParent() != BB) { + cast<Instruction>(Cmp->getOperand(0))->getParent() != BB) { Constant *RHSCst = cast<Constant>(Cmp->getOperand(1)); for (pred_iterator PI = pred_begin(BB), E = pred_end(BB);PI != E; ++PI){ @@ -472,20 +477,18 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ // Try to find a constant value for the LHS of an equality comparison, // and evaluate it statically if we can. - if (Cmp->getPredicate() == CmpInst::ICMP_EQ || - Cmp->getPredicate() == CmpInst::ICMP_NE) { + if (Constant *CmpConst = dyn_cast<Constant>(Cmp->getOperand(1))) { SmallVector<std::pair<ConstantInt*, BasicBlock*>, 8> LHSVals; ComputeValueKnownInPredecessors(I->getOperand(0), BB, LHSVals); - ConstantInt *True = ConstantInt::getTrue(I->getContext()); - ConstantInt *False = ConstantInt::getFalse(I->getContext()); - if (Cmp->getPredicate() == CmpInst::ICMP_NE) std::swap(True, False); - for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) { - if (LHSVals[i].first == Cmp->getOperand(1)) - Result.push_back(std::make_pair(True, LHSVals[i].second)); - else - Result.push_back(std::make_pair(False, LHSVals[i].second)); + if (LHSVals[i].first == 0) + Result.push_back(std::make_pair((ConstantInt*)0, + LHSVals[i].second)); + else if (Constant *Folded = ConstantExpr::getCompare( + Cmp->getPredicate(), LHSVals[i].first, CmpConst)) + Result.push_back(std::make_pair(cast<ConstantInt>(Folded), + LHSVals[i].second)); } return !Result.empty(); |