[llvm] [InstSimplify] Fix Inconsistent PHI Simplification (PR #113037)

[Matt Arsenault via llvm-commits]

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@@ -5288,6 +5288,70 @@ Value *llvm::simplifyExtractElementInst(Value *Vec, Value *Idx,
   return ::simplifyExtractElementInst(Vec, Idx, Q, RecursionLimit);
 }
 
+/// Try to fold the given arguments of a PHI function of array, struct, or
+/// vector types. Return true if this is possible and false otherwise.
+static bool getCommonPHIValueForAggregateOrVector(
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arsenm wrote:

Can you merge this with the select handling code? The core code looks the same 

https://github.com/llvm/llvm-project/pull/113037