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[InstCombine] Transform to undef incorrect atomic unordered mem intrinsics 

According to LangRef:
If len is not a positive integer multiple of element_size, then the behaviour of the intrinsic is undefined.

Add InstCombine rule to transform intrinsic to undef operation.

This is a follow-up for D76116.

Reviewers: reames
Reviewed By: reames
Subscribers: hiraditya, jfb, dantrushin, llvm-commits
Differential Revision: https://reviews.llvm.org/D76215
This commit is contained in:
Serguei Katkov 2020-03-16 14:15:28 +07:00
parent fa72b29bec
commit 80c351cdb6
2 changed files with 31 additions and 0 deletions
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12
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -1806,6 +1806,18 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
IntrinsicInst *II = dyn_cast<IntrinsicInst>(&CI);
if (!II) return visitCallBase(CI);
// For atomic unordered mem intrinsics if len is not a positive or
// not a multiple of element size then behavior is undefined.
if (auto *AMI = dyn_cast<AtomicMemIntrinsic>(II))
if (ConstantInt *NumBytes = dyn_cast<ConstantInt>(AMI->getLength()))
if (NumBytes->getSExtValue() < 0 ||
(NumBytes->getZExtValue() % AMI->getElementSizeInBytes() != 0)) {
CreateNonTerminatorUnreachable(AMI);
assert(AMI->getType()->isVoidTy() &&
"non void atomic unordered mem intrinsic");
return eraseInstFromFunction(*AMI);
}
// Intrinsics cannot occur in an invoke or a callbr, so handle them here
// instead of in visitCallBase.
if (auto *MI = dyn_cast<AnyMemIntrinsic>(II)) {

19
llvm/test/Transforms/InstCombine/element-atomic-memintrins.ll
View File

@ -415,4 +415,23 @@ define void @test_memcpy_loadstore_16(i8* %dest, i8* %src) {
ret void
}
define void @test_undefined(i8* %dest, i8* %src) {
; CHECK-LABEL: @test_undefined(
entry:
br i1 undef, label %ok, label %undefined
undefined:
; CHECK: undefined:
; CHECK-NEXT: store i1 true, i1* undef
; CHECK-NEXT: br label %ok
call void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i32(i8* align 16 %dest, i8* align 16 %src, i32 7, i32 4)
call void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i32(i8* align 16 %dest, i8* align 16 %src, i32 -8, i32 4)
call void @llvm.memmove.element.unordered.atomic.p0i8.p0i8.i32(i8* align 16 %dest, i8* align 16 %src, i32 7, i32 4)
call void @llvm.memmove.element.unordered.atomic.p0i8.p0i8.i32(i8* align 16 %dest, i8* align 16 %src, i32 -8, i32 4)
call void @llvm.memset.element.unordered.atomic.p0i8.i32(i8* align 16 %dest, i8 1, i32 7, i32 4)
call void @llvm.memset.element.unordered.atomic.p0i8.i32(i8* align 16 %dest, i8 1, i32 -8, i32 4)
br label %ok
ok:
ret void
}
declare void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i32(i8* nocapture writeonly, i8* nocapture readonly, i32, i32) nounwind argmemonly