[clang] [PAC] Ignore noexcept on function type when computing discriminator of member function pointers (PR #109056)

[John McCall via cfe-commits]

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@@ -3442,6 +3442,13 @@ uint16_t ASTContext::getPointerAuthTypeDiscriminator(QualType T) {
     encodeTypeForFunctionPointerAuth(*this, Out, T);
   } else {
     T = T.getUnqualifiedType();
+    // Drop exception specification from member function pointer type.
+    if (auto *MPT = T->getAs<MemberPointerType>())
+      if (MPT->isMemberFunctionPointer()) {
+        QualType FT =
+            getFunctionTypeWithExceptionSpec(MPT->getPointeeType(), EST_None);
+        T = getMemberPointerType(FT, MPT->getClass());
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rjmccall wrote:

Let's try to avoid rebuilding if the type already doesn't have an exception spec.

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