Make sure that ConstantExpr offsets also aren't off of extern

symbols.

Thanks to Duncan Sands for the testcase!

llvm-svn: 95877
This commit is contained in:
Eric Christopher 2010-02-11 17:44:04 +00:00
parent b1e50a8594
commit 2e0201ee18
2 changed files with 23 additions and 2 deletions

View File

@ -331,9 +331,15 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
if (CE->getOpcode() != Instruction::GetElementPtr) break;
GEPOperator *GEP = cast<GEPOperator>(CE);
// Make sure we're not a constant offset from an external
// global.
Value *Operand = GEP->getPointerOperand();
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Operand))
if (!GV->hasDefinitiveInitializer()) break;
// Get what we're pointing to and its size.
const PointerType *PT =
cast<PointerType>(GEP->getPointerOperand()->getType());
cast<PointerType>(Operand->getType());
size_t Size = TD->getTypeAllocSize(PT->getElementType());
// Get the current byte offset into the thing.
@ -345,7 +351,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
Constant *RetVal = ConstantInt::get(ReturnTy, Size-Offset);
return ReplaceInstUsesWith(CI, RetVal);
}
}
}
case Intrinsic::bswap:
// bswap(bswap(x)) -> x

View File

@ -48,4 +48,19 @@ define i1 @baz() nounwind {
ret i1 %2
}
define void @test1(i8* %q, i32 %x) nounwind noinline {
; CHECK: @test1
; CHECK: objectsize.i32
entry:
%0 = call i32 @llvm.objectsize.i32(i8* getelementptr inbounds ([0 x i8]* @window, i32 0, i32 10), i1 false) ; <i64> [#uses=1]
%1 = icmp eq i32 %0, -1 ; <i1> [#uses=1]
br i1 %1, label %"47", label %"46"
"46": ; preds = %entry
unreachable
"47": ; preds = %entry
unreachable
}
declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly