[llvm] [AMDGPU] Register allocation anti-hints to reduce MFMA hazard NOPs (PR #156943)

[Diana Picus via llvm-commits]

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@@ -29,6 +30,7 @@ class LiveRegMatrix;
 
 class LLVM_LIBRARY_VISIBILITY AllocationOrder {
   const SmallVector<MCPhysReg, 16> Hints;
+  SmallVector<MCPhysReg, 16> FilteredOrderStorage;
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rovka wrote:

```suggestion
  // Used as storage if the Order received in the constructor needs to be altered.
  SmallVector<MCPhysReg, 16> FilteredOrderStorage;
```

https://github.com/llvm/llvm-project/pull/156943