re PR c/34985 (Warning "defined but not used" despite __attribute__((__used__)))

2008-07-29  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR 34985
	* c-decl.c (merge_decls): Merge USED flags.
cp/
	* decl.c (duplicate_decls): Merge USED flags.
testsuite/
	* gcc.dg/pr34985.c: New.
	* g++.dg/warn/pr34985.C: New.

From-SVN: r138235

gcc/ChangeLog

+2008-07-29  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 34985
+	* c-decl.c (merge_decls): Merge USED flags.
+	
 2008-07-29  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	* config/sh/sh.c (sh_gimplify_va_arg_expr): Unshare the addr,

gcc/c-decl.c

@@ -1862,6 +1862,12 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype)
 
    extern_changed = DECL_EXTERNAL (olddecl) && !DECL_EXTERNAL (newdecl);
 
+   /* Merge the USED information.  */
+   if (TREE_USED (olddecl))
+     TREE_USED (newdecl) = 1;
+   else if (TREE_USED (newdecl))
+     TREE_USED (olddecl) = 1;
+
   /* Copy most of the decl-specific fields of NEWDECL into OLDDECL.
      But preserve OLDDECL's DECL_UID and DECL_CONTEXT.  */
   {

gcc/cp/ChangeLog

+2008-07-29  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 34985
+	* decl.c (duplicate_decls): Merge USED flags.
+	
 2008-07-27  Jason Merrill  <jason@redhat.com>
 
 	PR c++/36943

gcc/cp/decl.c

@@ -2056,6 +2056,12 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend)
       ggc_free (DECL_LANG_SPECIFIC (olddecl));
     }
 
+   /* Merge the USED information.  */
+   if (TREE_USED (olddecl))
+     TREE_USED (newdecl) = 1;
+   else if (TREE_USED (newdecl))
+     TREE_USED (olddecl) = 1;
+
   if (TREE_CODE (newdecl) == FUNCTION_DECL)
     {
       int function_size;

gcc/testsuite/ChangeLog

+2008-07-29  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
+	PR 34985
+	* gcc.dg/pr34985.c: New.
+	* g++.dg/warn/pr34985.C: New.
+	
 2008-07-29  Daniel Kraft  <d@domob.eu>
 
 	PR fortran/36403

gcc/testsuite/g++.dg/warn/pr34985.C

+/* PR34985: Warning "defined but not used" despite __attribute__((__used__)) */
+/* { dg-do compile } */
+/* { dg-options "-Wall -Wextra -O2" } */
+static void xxyyzz (void);
+static void __attribute__((__used__)) xxyyzz(void)
+{
+}
+
+/* { dg-final { scan-assembler "xxyyzz" } } */

gcc/testsuite/gcc.dg/pr34985.c

+/* PR34985: Warning "defined but not used" despite __attribute__((__used__)) */
+/* { dg-do compile } */
+/* { dg-options "-Wall -Wextra -O2" } */
+static void xxyyzz (void);
+static void __attribute__((__used__)) xxyyzz(void)
+{
+}
+
+/* { dg-final { scan-assembler "xxyyzz" } } */