From e2e86f6bca1c34490e97edf5ab2bb36e9bd4f799 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Fri, 8 Jul 2011 22:09:33 +0000 Subject: [PATCH] Reapply a fixed version of r133285. This tightens up checking for overflow in alloca sizes, based on feedback from Duncan and John about the change in r132926. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134749 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/InstCombine/InstCombineCasts.cpp | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp index 601d9b42f31..036f0d33678 100644 --- a/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -30,6 +30,14 @@ static Value *DecomposeSimpleLinearExpr(Value *Val, unsigned &Scale, } if (BinaryOperator *I = dyn_cast(Val)) { + // Cannot look past anything that might overflow. + OverflowingBinaryOperator *OBI = dyn_cast(Val); + if (OBI && !OBI->hasNoUnsignedWrap()) { + Scale = 1; + Offset = 0; + return Val; + } + if (ConstantInt *RHS = dyn_cast(I->getOperand(1))) { if (I->getOpcode() == Instruction::Shl) { // This is a value scaled by '1 << the shift amt'. @@ -71,11 +79,6 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI, // This requires TargetData to get the alloca alignment and size information. if (!TD) return 0; - // Insist that the amount-to-allocate not overflow. - OverflowingBinaryOperator *OBI = - dyn_cast(AI.getOperand(0)); - if (OBI && !(OBI->hasNoSignedWrap() || OBI->hasNoUnsignedWrap())) return 0; - const PointerType *PTy = cast(CI.getType()); BuilderTy AllocaBuilder(*Builder);