[clang] [clang] Allow C-style casts in constexpr in MS compatible mode (PR #197005)

[Shafik Yaghmour via cfe-commits]

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@@ -15633,3 +15633,17 @@ void ASTContext::recordOffsetOfEvaluation(const OffsetOfExpr *E) {
   if (FieldDecl *FD = Comp.getField(); isPFPField(FD))
     PFPFieldsWithEvaluatedOffset.insert(FD);
 }
+
+bool ASTContext::maybeFoldConstexprWithCast(
+    SmallVectorImpl<PartialDiagnosticAt> &Notes) const {
+  if (Notes.size() != 1 || !getLangOpts().MSVCCompat)
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shafik wrote:

I think I would prefer this split into two early exit w/ the `!getLangOpts().MSVCCompat` first.

https://github.com/llvm/llvm-project/pull/197005