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Fixed a transform crash when setting a negative size value for memset. Fixes PR12202. 

llvm-svn: 152756
This commit is contained in:
Aaron Ballman 2012-03-15 00:05:31 +00:00
parent abad002d55
commit a733297fa6
2 changed files with 26 additions and 2 deletions
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8
llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp
View File

@ -574,8 +574,9 @@ void ConvertToScalarInfo::ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI,
// transform it into a store of the expanded constant value.
if (MemSetInst *MSI = dyn_cast<MemSetInst>(User)) {
assert(MSI->getRawDest() == Ptr && "Consistency error!");
unsigned NumBytes = cast<ConstantInt>(MSI->getLength())->getZExtValue();
if (NumBytes != 0) {
signed SNumBytes = cast<ConstantInt>(MSI->getLength())->getSExtValue();
if (SNumBytes > 0) {
unsigned NumBytes = static_cast<unsigned>(SNumBytes);
unsigned Val = cast<ConstantInt>(MSI->getValue())->getZExtValue();
// Compute the value replicated the right number of times.
@ -1517,6 +1518,9 @@ void SROA::isSafeForScalarRepl(Instruction *I, uint64_t Offset,
ConstantInt *Length = dyn_cast<ConstantInt>(MI->getLength());
if (Length == 0)
return MarkUnsafe(Info, User);
if (Length->isNegative())
return MarkUnsafe(Info, User);
isSafeMemAccess(Offset, Length->getZExtValue(), 0,
UI.getOperandNo() == 0, Info, MI,
true /*AllowWholeAccess*/);

20
llvm/test/Transforms/ScalarRepl/negative-memset.ll Normal file
View File

@ -0,0 +1,20 @@
; PR12202
; RUN: opt < %s -scalarrepl -S
; Ensure that we do not hang or crash when feeding a negative value to memset
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f80:128:128-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S32"
target triple = "i686-pc-win32"
define i32 @test() nounwind {
entry:
%retval = alloca i32, align 4
%buff = alloca [1 x i8], align 1
store i32 0, i32* %retval
%0 = bitcast [1 x i8]* %buff to i8*
call void @llvm.memset.p0i8.i32(i8* %0, i8 0, i32 1, i32 1, i1 false)
%arraydecay = getelementptr inbounds [1 x i8]* %buff, i32 0, i32 0
call void @llvm.memset.p0i8.i32(i8* %arraydecay, i8 -1, i32 -8, i32 1, i1 false) ; Negative 8!
ret i32 0
}
declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind