[llvm] [AMDGPU] Ignore CU mode on targets without WGP mode (PR #219302)

[Matt Arsenault via llvm-commits]

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@@ -2599,7 +2599,9 @@ bool isGFX1250(const MCSubtargetInfo &STI) {
 }
 
 bool isFullSIMDMode(const MCSubtargetInfo &STI) {
-  return isGFX1250(STI) || !STI.getFeatureBits().test(FeatureCuMode);
+  // CU mode is only meaningful on targets that have WGP mode. Elsewhere the
+  // feature may still be requested (e.g. -mcumode), but it has no effect.
+  return !supportsWGP(STI) || !STI.getFeatureBits().test(FeatureCuMode);
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arsenm wrote:

The actual change here is to replace isGFX1250 with !supportsWGP

https://github.com/llvm/llvm-project/pull/219302