[llvm] Add EVT::changeVectorElementCount and MVT:changeVectorElementCount (PR #182266)

[Chaitanya Koparkar via llvm-commits]

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@@ -217,6 +217,13 @@ namespace llvm {
       return VecTy;
     }
 
+    /// Return a VT for a vector type whose attributes match ourselves with
+    /// the exception of the element count that is chosen by the caller.
+    MVT changeVectorElementCount(ElementCount EC) const {
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ckoparkar wrote:

@RKSimon I didn't find a place to use this function, could you please suggest one?

https://github.com/llvm/llvm-project/pull/182266