jdoerfert added inline comments.
================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp:581-584
+ if (ArgUsedToRetrieveHostcallPtr(I)) {
+ return false;
+ }
+ return true;
----------------
I'd suggest to switch the return value of ArgUsed... so it matches this
functions (and other callbacks).
================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp:566
+ return false;
+ };
+
----------------
sameerds wrote:
> jdoerfert wrote:
> > You can use AAPointerInfo for the call site return IRPosition. It will
> > (through the iterations) gather all accesses and put them into "bins" based
> > on offset and size. It deals with uses in calls, etc. and if there is stuff
> > missing it is better to add it in one place so we benefit throughout.
> I am not following what you have in mind. "implicitarg_ptr" is a pointer
> returned by an intrinsic that reads an ABI-defined register. I need to check
> that for a given call-graph, a particular range of bytes relative to that
> base pointer are never accessed. The above DFS on the uses conservatively
> assumes that such a load exists unless it can conclusively trace every use of
> the base pointer. This may include the pointer being passed to an extern
> function or being stored into a different memory location (although we don't
> expect ABI registers being capture this way). I am not seeing how to
> construct this around AAPointerInfo. As far as I can see, the public
> interface only talks about uses that are recognized as loads and stores.
Not actually tested, replaces the function body. Depends on D119249.
```
const auto PointerInfoAA = A.getAAFor<AAPointerInfo>(*this,
IRPosition::callback_returned(cast<CallBase>(Ptr)), DepClassTy::Required);
if (!PointerInfoAA.getState().isValidState())
return true; // Abort (which is weird as false is abort in the other CB).
AAPointerInfo::OffsetAndSize OAS(*Position, /* probably look pointer width up
in DL */ 8);
return !forallInterferingAccesses(OAS, [](const AAPointerInfo::Access &Acc,
bool IsExact) {
return Acc.getRemoteInst()->isDroppable(); });
```
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D119216/new/
https://reviews.llvm.org/D119216
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