[llvm] [AMDGPU][GlobalISel] Add register bank legalization for G_FADD (PR #163407)

[Petar Avramovic via llvm-commits]

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@@ -616,6 +616,24 @@ void RegBankLegalizeHelper::lowerSplitTo32(MachineInstr &MI) {
   MI.eraseFromParent();
 }
 
+void RegBankLegalizeHelper::lowerSplitTo16(MachineInstr &MI) {
+  Register Dst = MI.getOperand(0).getReg();
+  LLT DstTy = MRI.getType(Dst);
+  assert(DstTy == V2S16);
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petar-avramovic wrote:

```suggestion
  assert(MRI.getType(Dst) == V2S16);
```

https://github.com/llvm/llvm-project/pull/163407