[PATCH] D145524: [AMDGPU] Skip buffer_wbl2 before atomic fence acquire

[Tony Tye via Phabricator via llvm-commits]

t-tye requested changes to this revision.
t-tye added inline comments.
This revision now requires changes to proceed.


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Comment at: llvm/lib/Target/AMDGPU/SIMemoryLegalizer.cpp:2212
   if (MOI.isAtomic()) {
-    if (MOI.getOrdering() == AtomicOrdering::Acquire ||
-        MOI.getOrdering() == AtomicOrdering::Release ||
+    if (MOI.getOrdering() == AtomicOrdering::Acquire)
+      Changed |= CC->insertWait(MI, MOI.getScope(), MOI.getOrderingAddrSpace(),
----------------
Why is this waitcnt being added, I do not believe the memory model requires this. An acquire does not require previous memory operations to be complete. It only requires that the location being loaded has completed, followed by invalidating the caches consistent with the scope.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D145524/new/

https://reviews.llvm.org/D145524