[llvm] [clang-tools-extra] [clang] [AMDGPU][GFX12] Default component broadcast store (PR #76212)

[Matt Arsenault via cfe-commits]

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@@ -719,6 +719,18 @@ def FeatureFlatAtomicFaddF32Inst
   "Has flat_atomic_add_f32 instruction"
 >;
 
+def FeatureDefaultComponentZero : SubtargetFeature<"default-component-zero",
+  "HasDefaultComponentZero",
+  "true",
+  "BUFFER/IMAGE store instructions set unspecified components to zero"
+>;
+
+def FeatureDefaultComponentBroadcast : SubtargetFeature<"default-component-broadcast",
+  "HasDefaultComponentBroadcast",
+  "true",
+  "BUFFER/IMAGE store instructions set unspecified components to x component"
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arsenm wrote:

Probably should add gfx numbers to the description 

https://github.com/llvm/llvm-project/pull/76212