[clang] [RFC][Clang][AMDGPU] Emit only delta target-features to reduce IR bloat (PR #176533)

[Joseph Huber via cfe-commits]

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@@ -5606,6 +5606,12 @@ defm amdgpu_expand_waitcnt_profiling : BoolMOption<"amdgpu-expand-waitcnt-profil
   "emits waitcnt(N-1), waitcnt(N-2), ..., waitcnt(target). (AMDGPU only)">,
   NegFlag<SetFalse, [], [ClangOption]>>;
 
+def famdgpu_emit_full_target_features : Flag<["-"], "famdgpu-emit-full-target-features">,
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jhuber6 wrote:

I guess we've got plenty of other special AMDGPU clang flags, but I can't tell if this would actually be needed. We could potentially just expand the extra features from the CPU flag in LLVM but that's probably more code overall.

https://github.com/llvm/llvm-project/pull/176533