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[Attributor][FIX] Handle non-pointers when following uses

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When we follow uses, e.g., in AAMemoryBehavior or AANoCapture, we need
to make sure the value is a pointer before we ask for abstract
attributes only valid for pointers. This happens because we follow
pointers through calls that do not capture but may return the value.
This commit is contained in:
Johannes Doerfert 2020-01-10 12:32:24 -06:00
parent 9dcf889d15
commit ff6254dc26
3 changed files with 40 additions and 7 deletions
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21
llvm/lib/Transforms/IPO/Attributor.cpp
View File

@ -5074,10 +5074,14 @@ bool AAMemoryBehaviorFloating::followUsersOfUseIn(Attributor &A, const Use *U,
// general capturing of the underlying argument. The reason is that the // general capturing of the underlying argument. The reason is that the
// call might the argument "through return", which we allow and for which we // call might the argument "through return", which we allow and for which we
// need to check call users. // need to check call users.
unsigned ArgNo = ICS.getArgumentNo(U); if (U->get()->getType()->isPointerTy()) {
const auto &ArgNoCaptureAA = unsigned ArgNo = ICS.getArgumentNo(U);
A.getAAFor<AANoCapture>(*this, IRPosition::callsite_argument(ICS, ArgNo)); const auto &ArgNoCaptureAA = A.getAAFor<AANoCapture>(
return !ArgNoCaptureAA.isAssumedNoCapture(); *this, IRPosition::callsite_argument(ICS, ArgNo));
return !ArgNoCaptureAA.isAssumedNoCapture();
}
return true;
} }
void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use *U, void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use *U,
@ -5123,9 +5127,12 @@ void AAMemoryBehaviorFloating::analyzeUseIn(Attributor &A, const Use *U,
// Adjust the possible access behavior based on the information on the // Adjust the possible access behavior based on the information on the
// argument. // argument.
unsigned ArgNo = ICS.getArgumentNo(U); IRPosition Pos;
const IRPosition &ArgPos = IRPosition::callsite_argument(ICS, ArgNo); if (U->get()->getType()->isPointerTy())
const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(*this, ArgPos); Pos = IRPosition::callsite_argument(ICS, ICS.getArgumentNo(U));
else
Pos = IRPosition::callsite_function(ICS);
const auto &MemBehaviorAA = A.getAAFor<AAMemoryBehavior>(*this, Pos);
// "assumed" has at most the same bits as the MemBehaviorAA assumed // "assumed" has at most the same bits as the MemBehaviorAA assumed
// and at least "known". // and at least "known".
intersectAssumedBits(MemBehaviorAA.getAssumed()); intersectAssumedBits(MemBehaviorAA.getAssumed());

14
llvm/test/Transforms/Attributor/nocapture-1.ll
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@ -342,5 +342,19 @@ entry:
ret i8* %p ret i8* %p
} }
declare i8* @maybe_returned_ptr(i8* readonly %ptr) readonly nounwind
declare i8 @maybe_returned_val(i8* %ptr) readonly nounwind
declare void @val_use(i8 %ptr) readonly nounwind
; FIXME: Both pointers should be nocapture
define void @ptr_uses(i8* %ptr, i8* %wptr) {
; CHECK: define void @ptr_uses(i8* %ptr, i8* nocapture nonnull writeonly dereferenceable(1) %wptr)
%call_ptr = call i8* @maybe_returned_ptr(i8* %ptr)
%call_val = call i8 @maybe_returned_val(i8* %call_ptr)
call void @val_use(i8 %call_val)
store i8 0, i8* %wptr
ret void
}
declare i8* @llvm.launder.invariant.group.p0i8(i8*) declare i8* @llvm.launder.invariant.group.p0i8(i8*)
declare i8* @llvm.strip.invariant.group.p0i8(i8*) declare i8* @llvm.strip.invariant.group.p0i8(i8*)

12
llvm/test/Transforms/Attributor/readattrs.ll
View File

@ -195,3 +195,15 @@ define void @testbyval(i8* %read_only) {
ret void ret void
} }
;} ;}
declare i8* @maybe_returned_ptr(i8* readonly %ptr) readonly nounwind
declare i8 @maybe_returned_val(i8* %ptr) readonly nounwind
declare void @val_use(i8 %ptr) readonly nounwind
define void @ptr_uses(i8* %ptr) {
; ATTRIBUTOR: define void @ptr_uses(i8* nocapture readonly %ptr)
%call_ptr = call i8* @maybe_returned_ptr(i8* %ptr)
%call_val = call i8 @maybe_returned_val(i8* %call_ptr)
call void @val_use(i8 %call_val)
ret void
}