[compiler-rt] [Clang] Add __builtin_vectorelements to get number of elements in vector (PR #69010)

[Erich Keane via llvm-commits]

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@@ -5126,6 +5126,14 @@ void CXXNameMangler::mangleExpression(const Expr *E, unsigned Arity,
       Diags.Report(DiagID);
       return;
     }
+    case UETT_VectorElements: {
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erichkeane wrote:

We probably need the equivilent here for the MicrosoftMangle.cpp as well?

https://github.com/llvm/llvm-project/pull/69010