[PATCH] D42079: AMDGPU: Add a function attribute that shrinks buggy s_buffer opcodes on GFX9

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: lib/Target/AMDGPU/SIMachineFunctionInfo.cpp:165-166
 
+  if (F.hasFnAttribute("amdgpu-shrink-buggy-sbuffer-opcodes"))
+    ShrinkBuggySBufferLoadStoreAtomicxN = true;
+
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I don't understand why the function attribute for a hardware bug. If this happens to help other targets not working around the bug we should add an optimization to do this somewhere.


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Comment at: lib/Target/AMDGPU/SIShrinkInstructions.cpp:310-312
+      if (ST.hasBuggySBufferLoadStoreAtomicxN() &&
+          MFI->shrinkBuggySBufferLoadStoreAtomicxN() &&
+          TII->isSMRD(MI.getOpcode())) {
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We shouldn't be putting bug workarounds in an optimization pass. This should probably be part of the initial selection


Repository:
  rL LLVM

https://reviews.llvm.org/D42079