[llvm] [AMDGPU]: Rewrite mbcnt_lo/mbcnt_hi to work item ID where applicable (PR #160496)

[Matt Arsenault via llvm-commits]

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@@ -2113,6 +2119,181 @@ INITIALIZE_PASS_DEPENDENCY(UniformityInfoWrapperPass)
 INITIALIZE_PASS_END(AMDGPUCodeGenPrepare, DEBUG_TYPE, "AMDGPU IR optimizations",
                     false, false)
 
+bool AMDGPUCodeGenPrepareImpl::visitMbcntLo(IntrinsicInst &I) {
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arsenm wrote:

```suggestion
bool AMDGPUCodeGenPrepareImpl::visitMbcntLo(IntrinsicInst &I) const {
```

https://github.com/llvm/llvm-project/pull/160496