[clang] [llvm] [AMDGPU] Emit a waitcnt instruction after each memory instruction (PR #79236)

[Jun Wang via llvm-commits]

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@@ -167,6 +167,10 @@ def FeatureCuMode : SubtargetFeature<"cumode",
   "Enable CU wavefront execution mode"
 >;
 
+def FeaturePreciseMemory
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jwanggit86 wrote:

The function `hasFlag()` actually appears to be pretty expensive, and it's going to be called every time, regardless of whether the flag is used or not.

Let's get Matt's opinion on this. @arsenm What do you think?

https://github.com/llvm/llvm-project/pull/79236