[llvm] [AMDGPU][NFC] Add CuModeOnly feature (PR #201134)

[Jay Foad via llvm-commits]

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@@ -236,6 +236,13 @@ def FeatureCuMode : SubtargetFeature<"cumode",
   "Enable CU wavefront execution mode"
 >;
 
+defm CuModeOnly : AMDGPUSubtargetFeature<"cumode-only",
+  "Target supports only CU mode",
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jayfoad wrote:

> I thought the hardware renamed this to something else?

In GFX13 CU mode is renamed to "half-WGP mode", at least in some docs.

https://github.com/llvm/llvm-project/pull/201134