[llvm] [DAG] Add MVT::widenIntegerElementType and MVT::widenIntegerVectorElementType (PR #206850)

[Simon Pilgrim via llvm-commits]

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@@ -265,6 +265,28 @@ namespace llvm {
       return MVT::getVectorVT(EltVT, EltCnt * 2);
     }
 
+    // Return a VT for an Integer type doubled in size
+    MVT widenIntegerElementType() const {
+      assert(isScalarInteger() && "Not an integer MVT!");
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RKSimon wrote:

Can we use widenIntegerElementType for scalars AND vectors? I'm hoping #206726 will make this trivial.

https://github.com/llvm/llvm-project/pull/206850