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[Attributor] Fix callsite check in AAUndefinedBehavior 

This is the next patch of D86842
When we check `noundef` attribute violation at callsites, we do not have to require `nonnull` in the following two cases.
1. An argument is known to be simplified to undef
2. An argument is known to be dead

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86845
This commit is contained in:
Shinji Okumura 2020-08-30 13:17:02 +09:00
parent 7082381735
commit a7ca9e09bd
2 changed files with 79 additions and 20 deletions
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41
llvm/lib/Transforms/IPO/AttributorAttributes.cpp
View File

@ -2019,34 +2019,35 @@ struct AAUndefinedBehaviorImpl : public AAUndefinedBehavior {
if (idx >= Callee->arg_size())
break;
Value *ArgVal = CB.getArgOperand(idx);
if (!ArgVal || !ArgVal->getType()->isPointerTy())
continue;
IRPosition CalleeArgumentIRP = IRPosition::callsite_argument(CB, idx);
if (!CalleeArgumentIRP.hasAttr({Attribute::NoUndef}))
continue;
auto &NonNullAA = A.getAAFor<AANonNull>(*this, CalleeArgumentIRP,
/* TrackDependence */ false);
if (!NonNullAA.isKnownNonNull())
continue;
const auto &ValueSimplifyAA = A.getAAFor<AAValueSimplify>(
*this, IRPosition::value(*ArgVal), /* TrackDependence */ false);
Optional<Value *> SimplifiedVal =
ValueSimplifyAA.getAssumedSimplifiedValue(A);
if (!ValueSimplifyAA.isKnown())
if (!ArgVal)
continue;
// Here, we handle three cases.
// (1) Not having a value means it is dead. (we can replace the value
// with undef)
// (2) Simplified to null pointer. The argument is a poison value and
// violate noundef attribute.
// (3) Simplified to undef. The argument violate noundef attriubte.
// (2) Simplified to undef. The argument violate noundef attriubte.
// (3) Simplified to null pointer where known to be nonnull.
// The argument is a poison value and violate noundef attribute.
IRPosition CalleeArgumentIRP = IRPosition::callsite_argument(CB, idx);
if (!CalleeArgumentIRP.hasAttr({Attribute::NoUndef}))
continue;
auto &ValueSimplifyAA = A.getAAFor<AAValueSimplify>(
*this, IRPosition::value(*ArgVal), /* TrackDependence */ false);
if (!ValueSimplifyAA.isKnown())
continue;
Optional<Value *> SimplifiedVal =
ValueSimplifyAA.getAssumedSimplifiedValue(A);
if (!SimplifiedVal.hasValue() ||
isa<ConstantPointerNull>(*SimplifiedVal.getValue()) ||
isa<UndefValue>(*SimplifiedVal.getValue())) {
KnownUBInsts.insert(&I);
return true;
continue;
}
if (!ArgVal->getType()->isPointerTy() ||
!isa<ConstantPointerNull>(*SimplifiedVal.getValue()))
continue;
auto &NonNullAA = A.getAAFor<AANonNull>(*this, CalleeArgumentIRP,
/* TrackDependence */ false);
if (NonNullAA.isKnownNonNull())
KnownUBInsts.insert(&I);
}
return true;
};

58
llvm/test/Transforms/Attributor/undefined_behavior.ll
View File

@ -1087,3 +1087,61 @@ define void @callsite_noundef_2() {
call void @callee_ptr_arg(i32* noundef undef)
ret void
}
define i32 @argument_noundef1(i32 noundef %c) {
; IS__TUNIT____: Function Attrs: nofree nosync nounwind readnone willreturn
; IS__TUNIT____-LABEL: define {{[^@]+}}@argument_noundef1
; IS__TUNIT____-SAME: (i32 noundef returned [[C:%.*]]) [[ATTR0]] {
; IS__TUNIT____-NEXT: ret i32 [[C]]
;
; IS__CGSCC____: Function Attrs: nofree norecurse nosync nounwind readnone willreturn
; IS__CGSCC____-LABEL: define {{[^@]+}}@argument_noundef1
; IS__CGSCC____-SAME: (i32 noundef returned [[C:%.*]]) [[ATTR0]] {
; IS__CGSCC____-NEXT: ret i32 [[C]]
;
ret i32 %c
}
define i32 @violate_noundef_nonpointer() {
; IS__TUNIT____: Function Attrs: nofree nosync nounwind readnone willreturn
; IS__TUNIT____-LABEL: define {{[^@]+}}@violate_noundef_nonpointer
; IS__TUNIT____-SAME: () [[ATTR0]] {
; IS__TUNIT____-NEXT: unreachable
;
; IS__CGSCC____: Function Attrs: nofree norecurse nosync nounwind readnone willreturn
; IS__CGSCC____-LABEL: define {{[^@]+}}@violate_noundef_nonpointer
; IS__CGSCC____-SAME: () [[ATTR0]] {
; IS__CGSCC____-NEXT: unreachable
;
%ret = call i32 @argument_noundef1(i32 undef)
ret i32 %ret
}
define i32* @argument_noundef2(i32* noundef %c) {
; IS__TUNIT____: Function Attrs: nofree nosync nounwind readnone willreturn
; IS__TUNIT____-LABEL: define {{[^@]+}}@argument_noundef2
; IS__TUNIT____-SAME: (i32* nofree noundef readnone returned "no-capture-maybe-returned" [[C:%.*]]) [[ATTR0]] {
; IS__TUNIT____-NEXT: ret i32* [[C]]
;
; IS__CGSCC____: Function Attrs: nofree norecurse nosync nounwind readnone willreturn
; IS__CGSCC____-LABEL: define {{[^@]+}}@argument_noundef2
; IS__CGSCC____-SAME: (i32* nofree noundef readnone returned "no-capture-maybe-returned" [[C:%.*]]) [[ATTR0]] {
; IS__CGSCC____-NEXT: ret i32* [[C]]
;
ret i32* %c
}
define i32* @violate_noundef_pointer() {
; IS__TUNIT____: Function Attrs: nofree nosync nounwind readnone willreturn
; IS__TUNIT____-LABEL: define {{[^@]+}}@violate_noundef_pointer
; IS__TUNIT____-SAME: () [[ATTR0]] {
; IS__TUNIT____-NEXT: unreachable
;
; IS__CGSCC____: Function Attrs: nofree norecurse nosync nounwind readnone willreturn
; IS__CGSCC____-LABEL: define {{[^@]+}}@violate_noundef_pointer
; IS__CGSCC____-SAME: () [[ATTR0]] {
; IS__CGSCC____-NEXT: unreachable
;
%ret = call i32* @argument_noundef2(i32* undef)
ret i32* %ret
}