commit e924f74640ecd18240fb514f99b0d5b5ceeeffb7
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Sep 2 16:32:15 2015 -0400

    	PR c++/44282
    
    	* mangle.c (write_CV_qualifiers_for_type): Also warn about regparm
    	mangling with lower -fabi-version.

diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 342cb93..2640d52 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -2196,7 +2196,7 @@ write_CV_qualifiers_for_type (const tree type)
      We don't do this with classes and enums because their attributes
      are part of their definitions, not something added on.  */
 
-  if (abi_version_at_least (10) && !OVERLOAD_TYPE_P (type))
+  if (!OVERLOAD_TYPE_P (type))
     {
       auto_vec<tree> vec;
       for (tree a = TYPE_ATTRIBUTES (type); a; a = TREE_CHAIN (a))
@@ -2207,31 +2207,34 @@ write_CV_qualifiers_for_type (const tree type)
 	      && !is_attribute_p ("abi_tag", name))
 	    vec.safe_push (a);
 	}
-      vec.qsort (attr_strcmp);
-      while (!vec.is_empty())
+      if (abi_version_crosses (10) && !vec.is_empty ())
+	G.need_abi_warning = true;
+      if (abi_version_at_least (10))
 	{
-	  tree a = vec.pop();
-	  const attribute_spec *as
-	    = lookup_attribute_spec (get_attribute_name (a));
-
-	  write_char ('U');
-	  write_unsigned_number (strlen (as->name));
-	  write_string (as->name);
-	  if (TREE_VALUE (a))
+	  vec.qsort (attr_strcmp);
+	  while (!vec.is_empty())
 	    {
-	      write_char ('I');
-	      for (tree args = TREE_VALUE (a); args;
-		   args = TREE_CHAIN (args))
+	      tree a = vec.pop();
+	      const attribute_spec *as
+		= lookup_attribute_spec (get_attribute_name (a));
+
+	      write_char ('U');
+	      write_unsigned_number (strlen (as->name));
+	      write_string (as->name);
+	      if (TREE_VALUE (a))
 		{
-		  tree arg = TREE_VALUE (args);
-		  write_template_arg (arg);
+		  write_char ('I');
+		  for (tree args = TREE_VALUE (a); args;
+		       args = TREE_CHAIN (args))
+		    {
+		      tree arg = TREE_VALUE (args);
+		      write_template_arg (arg);
+		    }
+		  write_char ('E');
 		}
-	      write_char ('E');
+
+	      ++num_qualifiers;
 	    }
-
-	  ++num_qualifiers;
-	  if (abi_version_crosses (10))
-	    G.need_abi_warning = true;
 	}
     }
 
diff --git a/gcc/testsuite/g++.dg/abi/mangle-regparm1a.C b/gcc/testsuite/g++.dg/abi/mangle-regparm1a.C
new file mode 100644
index 0000000..bfa6c9b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/mangle-regparm1a.C
@@ -0,0 +1,21 @@
+// { dg-do run { target { { i?86-*-* x86_64-*-* } && ia32 } } }
+// { dg-options "-fabi-version=8 -Wabi -save-temps" }
+// { dg-final { scan-assembler "_Z18IndirectExternCallIPFviiEiEvT_T0_S3_" } }
+
+template <typename F, typename T>
+void IndirectExternCall(F f, T t1, T t2) { // { dg-warning "mangled name" }
+  typedef F (*WrapF)(F);
+  f (t1, t2);
+}
+
+__attribute__((regparm(3), stdcall))
+void regparm_func (int i, int j)
+{
+  if (i != 24 || j != 42)
+    __builtin_abort();
+}
+
+int main()
+{
+  IndirectExternCall (regparm_func, 24, 42);
+}