From 1d2fd19df60de6b0776e4e18616d7a8eadd72608 Mon Sep 17 00:00:00 2001 From: Victor Hernandez Date: Mon, 2 Nov 2009 18:51:28 +0000 Subject: [PATCH] Set bit instead of calling pow() to compute 2 << n llvm-svn: 85814 --- lib/Analysis/MemoryBuiltins.cpp | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp index 4ebfa966421..eb74ae4b205 100644 --- a/lib/Analysis/MemoryBuiltins.cpp +++ b/lib/Analysis/MemoryBuiltins.cpp @@ -16,6 +16,7 @@ #include "llvm/Constants.h" #include "llvm/Instructions.h" #include "llvm/Module.h" +#include "llvm/ADT/APInt.h" #include "llvm/Analysis/ConstantFolding.h" using namespace llvm; @@ -156,15 +157,22 @@ static Value* isArrayMallocHelper(const CallInst *CI, LLVMContext &Context, return Op1; } if (Opcode == Instruction::Shl) { - ConstantInt* Op1Int = dyn_cast(Op1); - if (!Op1Int) return NULL; - Value* Op1Pow = ConstantInt::get(Op1->getType(), (uint64_t) - pow(2.0, (double) Op1Int->getZExtValue())); + ConstantInt* Op1CI = dyn_cast(Op1); + if (!Op1CI) return NULL; + + APInt Op1Int = Op1CI->getValue(); + unsigned Op1Width = Op1Int.getBitWidth(); + // check for overflow + if (Op1Int.getActiveBits() > 64 || Op1Int.getZExtValue() > Op1Width) + return NULL; + Value* Op1Pow = ConstantInt::get(Context, + APInt(Op1Width, 0).set(Op1Int.getZExtValue())); + if (Op0 == ElementSize || (FoldedElementSize && Op0 == FoldedElementSize)) // ArraySize << log2(ElementSize) return Op1Pow; if (Op1Pow == ElementSize || - (FoldedElementSize && Op1Pow == FoldedElementSize)) + (FoldedElementSize && Op1Pow == FoldedElementSize)) // ElementSize << log2(ArraySize) return Op0; }