[llvm] [AMDGPU] Generate waterfall for calls with SGPR(inreg) argument (PR #146997)

[Matt Arsenault via llvm-commits]

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@@ -143,6 +151,7 @@ class SIFixSGPRCopies {
   bool needToBeConvertedToVALU(V2SCopyInfo *I);
   void analyzeVGPRToSGPRCopy(MachineInstr *MI);
   void lowerVGPR2SGPRCopies(MachineFunction &MF);
+  void lowerPysicalSGPRInsts(MachineFunction &MF);
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arsenm wrote:

```suggestion
  void lowerPhysicalSGPRInsts(MachineFunction &MF);
```

https://github.com/llvm/llvm-project/pull/146997