[clang] [PAC] Re-sign a pointer to a noexcept member function when it is converted to a pointer to a member function without noexcept (PR #109056)

[John McCall via cfe-commits]

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@@ -2419,8 +2419,13 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
     return Visit(const_cast<Expr*>(E));
 
   case CK_NoOp: {
-    return CE->changesVolatileQualification() ? EmitLoadOfLValue(CE)
-                                              : Visit(const_cast<Expr *>(E));
+    if (CE->changesVolatileQualification())
+      return EmitLoadOfLValue(CE);
+    auto V = Visit(const_cast<Expr *>(E));
+    if (CGF.CGM.getCodeGenOpts().PointerAuth.CXXMemberFunctionPointers &&
+        CE->getType()->isMemberFunctionPointerType())
+      V = CGF.CGM.getCXXABI().EmitMemberPointerConversion(CGF, CE, V);
+    return V;
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rjmccall wrote:

Why do we not need similar logic here when casting function pointer types when function pointer type diversity is enabled?  Does Sema not use `CK_NoOp` for those?  Maybe we should do the same for member pointer conversions and make sure there's a better cast kind to use.

https://github.com/llvm/llvm-project/pull/109056