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

[Lawrence Benson via cfe-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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lawben wrote:

I don't know. But none of the other `UETT_*` types are covered in `MicrosoftMangle.cpp`. I'm not sure whether they are missing or if it not necessary to add this.

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