[llvm] [AMDGPU] Re-Re-apply: Implement vop3p complex pattern optmization for gisel (PR #146984)

[Juan Manuel Martinez Caamaño via llvm-commits]

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@@ -4563,6 +4563,7 @@ static SrcStatus getNegStatus(Register Reg, SrcStatus S,
   default:
     llvm_unreachable("unexpected SrcStatus");
   }
+  llvm_unreachable("unexpected SrcStatus");
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jmmartinez wrote:

"unexpected SrcStatus & NegType combination" ?

Or maybe break in the default case to avoid having the duplicated unreachable.

https://github.com/llvm/llvm-project/pull/146984