[llvm] [LV] Remove common extends and selects in CSE (PR #147731)

[Sam Tebbs via llvm-commits]

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@@ -804,6 +804,10 @@ int FunctionComparator::cmpOperations(const Instruction *L,
         return Res;
     }
   }
+  if (const CastInst *Cast = dyn_cast<CastInst>(L)) {
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SamTebbs33 wrote:

I think you're right about this being caught by the earlier check. Added a test to make sure.

https://github.com/llvm/llvm-project/pull/147731