From 1d548d851a2b04138bf939ab65c0054bdba6052a Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Fri, 17 Jul 2009 22:25:10 +0000 Subject: Make BasicAliasAnalysis and Value::getUnderlyingObject use GEPOperator's hasNoPointer0verflow(), and make a few places in instcombine that create GEPs that may overflow clear the NoOverflow value. Among other things, this partially addresses PR2831. llvm-svn: 76252 --- llvm/lib/Analysis/BasicAliasAnalysis.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'llvm/lib/Analysis/BasicAliasAnalysis.cpp') diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp index c10c6f3f279..dcb5903a14e 100644 --- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp +++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp @@ -23,6 +23,7 @@ #include "llvm/Instructions.h" #include "llvm/IntrinsicInst.h" #include "llvm/LLVMContext.h" +#include "llvm/Operator.h" #include "llvm/Pass.h" #include "llvm/Target/TargetData.h" #include "llvm/ADT/SmallVector.h" @@ -38,10 +39,11 @@ using namespace llvm; //===----------------------------------------------------------------------===// static const User *isGEP(const Value *V) { - if (isa(V) || - (isa(V) && - cast(V)->getOpcode() == Instruction::GetElementPtr)) - return cast(V); + if (const GEPOperator *GEP = dyn_cast(V)) + // For the purposes of BasicAliasAnalysis, if the GEP has overflow it + // could do crazy things. + if (GEP->hasNoPointerOverflow()) + return GEP; return 0; } -- cgit v1.2.3