[Mlir-commits] [clang] [llvm] [mlir] [AMDGPU] Fix missing cache bypass scope on seq_cst buffer fat pointer atomics (PR #213585)

[Krzysztof Drewniak]

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@@ -1527,6 +1557,13 @@ void SITargetLowering::getTgtMemIntrinsic(SmallVectorImpl<IntrinsicInfo> &Infos,
           // XXX - Should this be volatile without known ordering?
           Info.flags |= MachineMemOperand::MOVolatile;
           Info.memVT = MVT::getVT(CI.getArgOperand(0)->getType());
+          if (std::optional<SyncScope::ID> SSID =
+                  parseBufferAtomicScopeArg(CI)) {
+            // Pretend to be atomic so expandAtomicCmpxchgOrRmw sets cache
+            // bypass bits.
+            Info.order = AtomicOrdering::Monotonic;
+            Info.ssid = *SSID;
+          }
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krzysz00 wrote:

Ok, so yeah, what we could do is "not atomic" is the empty metadata node, and an atomic is a `{oldering, scope}` node.

Assuming that we're not just going to handle this in LowerBufferFatPointers

https://github.com/llvm/llvm-project/pull/213585