[llvm-branch-commits] [llvm] AMDGPU/GlobalISel: Add waterfall lowering in regbanklegalize (PR #142790)

[Pierre van Houtryve via llvm-branch-commits]

================
@@ -203,7 +205,14 @@ class AMDGPURegBankLegalizeCombiner {
   bool tryEliminateReadAnyLane(MachineInstr &Copy) {
     Register Dst = Copy.getOperand(0).getReg();
     Register Src = Copy.getOperand(1).getReg();
-    if (!Src.isVirtual())
+
+    // Skip non-vgpr Dst
+    if ((Dst.isVirtual() && MRI.getRegBankOrNull(Dst) != VgprRB) ||
+        (Dst.isPhysical() && !TRI.isVGPR(MRI, Dst)))
----------------
Pierre-vh wrote:

```suggestion
    if (Dst.isVirtual() ? (MRI.getRegBankOrNull(Dst) != VgprRB) :  !TRI.isVGPR(MRI, Dst))
```

https://github.com/llvm/llvm-project/pull/142790