[llvm] [AMDGPU] Set glc/slc on volatile/nontemporal SMEM loads (PR #77443)

[Tony Tye via llvm-commits]

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@@ -29,7 +29,6 @@ class SM_Pseudo <string opName, dag outs, dag ins, string asmOps, list<dag> patt
   let mayStore = 0;
   let mayLoad = 1;
   let hasSideEffects = 0;
-  let maybeAtomic = 0;
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t-tye wrote:

How does removing this cause SIMemoryLegalizer to process scalar loads and stores?

Should the memory model in AMDGPUUsage be updated to include the scalar memory instructions?

https://github.com/llvm/llvm-project/pull/77443