[llvm] [AMDGPU][True16][CodeGen] fix moveToVALU with proper subreg access in true16 (PR #132089)

[Joe Nash via llvm-commits]

================
@@ -7744,6 +7744,29 @@ void SIInstrInfo::moveToVALUImpl(SIInstrWorklist &Worklist,
       Inst.setDesc(get(AMDGPU::IMPLICIT_DEF));
       return;
     }
+
+    // in true16 mode, if this is a v2s copy src between vgpr16 and sgpr32,
----------------
Sisyph wrote:

```suggestion
    // If this is a copy from vgpr16 to sgpr32,
```

https://github.com/llvm/llvm-project/pull/132089