[clang] [llvm] [AMDGPU][SIInsertWaitcnt] Implement Waitcnt Expansion for Profiling (PR #169345)

[Matt Arsenault via cfe-commits]

================
@@ -443,6 +443,8 @@ void AMDGPUTargetCodeGenInfo::setTargetAttributes(
     setFunctionDeclAttributes(FD, F, M);
   if (!getABIInfo().getCodeGenOpts().EmitIEEENaNCompliantInsts)
     F->addFnAttr("amdgpu-ieee", "false");
+  if (getABIInfo().getCodeGenOpts().AMDGPUExpandWaitcntProfiling)
+    F->addFnAttr("amdgpu-expand-waitcnt-profiling");
----------------
arsenm wrote:

This attribute should be documented in AMDGPUUsage 

https://github.com/llvm/llvm-project/pull/169345