[llvm] [AMDGPU] Fix waterfall inreg call args on gfx90a: hoist defs + avoid AGPR sources (PR #194890)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,47 @@
+; RUN: llc -mtriple=amdgcn -mcpu=gfx90a -O3 -verify-machineinstrs < %s | FileCheck %s
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arsenm wrote:

```suggestion
; RUN: llc -mtriple=amdgcn -mcpu=gfx90a < %s | FileCheck %s
```

https://github.com/llvm/llvm-project/pull/194890