diff options
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 52 |
1 files changed, 26 insertions, 26 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index d6e64012126..a48b935f88a 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -6218,33 +6218,33 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) { } break; - case Instruction::Shl: - // Turn shift left of a constant amount into a multiply. - if (ConstantInt *SA = dyn_cast<ConstantInt>(BO->RHS)) { - uint32_t BitWidth = cast<IntegerType>(SA->getType())->getBitWidth(); - - // If the shift count is not less than the bitwidth, the result of - // the shift is undefined. Don't try to analyze it, because the - // resolution chosen here may differ from the resolution chosen in - // other parts of the compiler. - if (SA->getValue().uge(BitWidth)) - break; - - // It is currently not resolved how to interpret NSW for left - // shift by BitWidth - 1, so we avoid applying flags in that - // case. Remove this check (or this comment) once the situation - // is resolved. See - // http://lists.llvm.org/pipermail/llvm-dev/2015-April/084195.html - // and http://reviews.llvm.org/D8890 . - auto Flags = SCEV::FlagAnyWrap; - if (BO->Op && SA->getValue().ult(BitWidth - 1)) - Flags = getNoWrapFlagsFromUB(BO->Op); + case Instruction::Shl: + // Turn shift left of a constant amount into a multiply. + if (ConstantInt *SA = dyn_cast<ConstantInt>(BO->RHS)) { + uint32_t BitWidth = cast<IntegerType>(SA->getType())->getBitWidth(); + + // If the shift count is not less than the bitwidth, the result of + // the shift is undefined. Don't try to analyze it, because the + // resolution chosen here may differ from the resolution chosen in + // other parts of the compiler. + if (SA->getValue().uge(BitWidth)) + break; - Constant *X = ConstantInt::get(getContext(), - APInt::getOneBitSet(BitWidth, SA->getZExtValue())); - return getMulExpr(getSCEV(BO->LHS), getSCEV(X), Flags); - } - break; + // It is currently not resolved how to interpret NSW for left + // shift by BitWidth - 1, so we avoid applying flags in that + // case. Remove this check (or this comment) once the situation + // is resolved. See + // http://lists.llvm.org/pipermail/llvm-dev/2015-April/084195.html + // and http://reviews.llvm.org/D8890 . + auto Flags = SCEV::FlagAnyWrap; + if (BO->Op && SA->getValue().ult(BitWidth - 1)) + Flags = getNoWrapFlagsFromUB(BO->Op); + + Constant *X = ConstantInt::get( + getContext(), APInt::getOneBitSet(BitWidth, SA->getZExtValue())); + return getMulExpr(getSCEV(BO->LHS), getSCEV(X), Flags); + } + break; case Instruction::AShr: { // AShr X, C, where C is a constant. |
