[clang] [CIR] Upstream splat op for VectorType (PR #139827)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -2037,4 +2037,37 @@ def VecExtractOp : CIR_Op<"vec.extract", [Pure,
   let hasFolder = 1;
 }
 
+
+//===----------------------------------------------------------------------===//
+// VecSplat
+//===----------------------------------------------------------------------===//
+
+// cir.vec.splat is a separate operation from cir.vec.create because more
+// efficient LLVM IR can be generated for it, and because some optimization and
+// analysis passes can benefit from knowing that all elements of the vector
+// have the same value.
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bcardosolopes wrote:

Seems like this should be part of the description proper?

https://github.com/llvm/llvm-project/pull/139827