[llvm] [AMDGPU] Add IR LiveReg type-based optimization (PR #66838)

[Matt Arsenault via llvm-commits]

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@@ -341,6 +342,85 @@ class AMDGPUCodeGenPrepare : public FunctionPass {
   StringRef getPassName() const override { return "AMDGPU IR optimizations"; }
 };
 
+class LiveRegConversion {
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arsenm wrote:

It's not obvious to me what this name means

https://github.com/llvm/llvm-project/pull/66838