From 1f8f2d52ff3712770a49f318a687b0c8b0ada9d0 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Tue, 24 May 2011 07:43:19 +0000
Subject: [PATCH] Fix a bug in -Wundefined-reinterpret-cast where we failed to
 look through sugared types when testing for TagTypes. This was the actual
 cause of the only false positive in Clang+LLVM.

Next evaluation will be over a much larger selection of code including
large amounts of open source code.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131957 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaCXXCast.cpp          | 2 +-
 test/SemaCXX/reinterpret-cast.cpp | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/Sema/SemaCXXCast.cpp b/lib/Sema/SemaCXXCast.cpp
index c7038322e1..32fd0be375 100644
--- a/lib/Sema/SemaCXXCast.cpp
+++ b/lib/Sema/SemaCXXCast.cpp
@@ -1330,7 +1330,7 @@ void Sema::CheckCompatibleReinterpretCast(QualType SrcType, QualType DestType,
     return;
   }
   // or one of the types is a tag type.
-  if (isa<TagType>(SrcTy) || isa<TagType>(DestTy)) {
+  if (SrcTy->getAs<TagType>() || DestTy->getAs<TagType>()) {
     return;
   }
 
diff --git a/test/SemaCXX/reinterpret-cast.cpp b/test/SemaCXX/reinterpret-cast.cpp
index 449fecb160..68005a5270 100644
--- a/test/SemaCXX/reinterpret-cast.cpp
+++ b/test/SemaCXX/reinterpret-cast.cpp
@@ -119,9 +119,13 @@ namespace PR9564 {
 
 void dereference_reinterpret_cast() {
   struct A {};
+  typedef A A2;
   class B {};
+  typedef B B2;
   A a;
   B b;
+  A2 a2;
+  B2 b2;
   long l;
   double d;
   float f;
@@ -142,6 +146,10 @@ void dereference_reinterpret_cast() {
   (void)*reinterpret_cast<A*>(&b);
   (void)reinterpret_cast<B&>(a);
   (void)*reinterpret_cast<B*>(&a);
+  (void)reinterpret_cast<A2&>(b2);
+  (void)*reinterpret_cast<A2*>(&b2);
+  (void)reinterpret_cast<B2&>(a2);
+  (void)*reinterpret_cast<B2*>(&a2);
 
   // Casting to itself is allowed
   (void)reinterpret_cast<A&>(a);