C++ PATCH for c++/45267 (always_inline sorry in 4.5)

[Jason Merrill]

duplicate_decls was dropping DECL_DISREGARD_INLINE_LIMITS, but leaving 
the always_inline attribute in DECL_ATTRIBUTES, leading to confusion. 
This patch keeps them in sync.

Tested x86_64-pc-linux-gnu, applying to trunk and 4.5 (not 4.6).
commit 679e5e90918506d6792b8c0b19deff0f1a497298
Author: Jason Merrill <ja...@redhat.com>
Date:   Mon Apr 18 17:35:35 2011 -0700
        PR c++/45267
        * decl.c (duplicate_decls): Keep always_inline attribute
        in sync with DECL_DISREGARD_INLINE_LIMITS.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 794832b..6309648 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2052,6 +2052,19 @@ duplicate_decls (tree newdecl, tree olddecl, bool 
newdecl_is_friend)
 
          /* [temp.expl.spec/14] We don't inline explicit specialization
             just because the primary template says so.  */
+
+         /* But still keep DECL_DISREGARD_INLINE_LIMITS in sync with
+            the always_inline attribute.  */
+         if (DECL_DISREGARD_INLINE_LIMITS (olddecl)
+             && !DECL_DISREGARD_INLINE_LIMITS (newdecl))
+           {
+             if (DECL_DECLARED_INLINE_P (newdecl))
+               DECL_DISREGARD_INLINE_LIMITS (newdecl) = true;
+             else
+               DECL_ATTRIBUTES (newdecl)
+                 = remove_attribute ("always_inline",
+                                     DECL_ATTRIBUTES (newdecl));
+           }
        }
       else if (new_defines_function && DECL_INITIAL (olddecl))
        {
diff --git a/gcc/testsuite/g++.dg/ext/attrib41.C 
b/gcc/testsuite/g++.dg/ext/attrib41.C
new file mode 100644
index 0000000..368554a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attrib41.C
@@ -0,0 +1,19 @@
+// PR c++/45267
+// { dg-options "-O" }
+
+template<typename T> struct Vector {
+  Vector(long long x);
+  inline Vector<T> operator<<(int x) const __attribute__((always_inline));
+};
+long long bar (long long);
+template<> inline Vector<int> Vector<int>::operator<<(int x) const {
+  return bar(x);
+}
+bool b;
+int main() {
+  Vector<int> a(1);
+  if ((a << 2), b) {
+    a << 2;
+    throw 1;
+  }
+}