c.opt (Wpacked-bitfield-compat): Change init value to -1.

	* c.opt (Wpacked-bitfield-compat): Change init value to -1.
	* c-opts.c (c_common_post_options): If -W*packed-bitfield-compat
	was not supplied then set warn_packed_bitfield_compat to the
	default value of 1.
	* stor-layout.c (place_field): Check warn_packed_bitfield_compat
	against 1.

From-SVN: r143718

gcc/ChangeLog

+2009-01-27  Adam Nemet  <anemet@caviumnetworks.com>
+
+	* c.opt (Wpacked-bitfield-compat): Change init value to -1.
+	* c-opts.c (c_common_post_options): If -W*packed-bitfield-compat
+	was not supplied then set warn_packed_bitfield_compat to the
+	default value of 1.
+	* stor-layout.c (place_field): Check warn_packed_bitfield_compat
+	against 1.
+
 2009-01-27  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/38503

gcc/c-opts.c

@@ -1085,6 +1085,11 @@ c_common_post_options (const char **pfilename)
   if (warn_sign_conversion == -1)
     warn_sign_conversion =  (c_dialect_cxx ()) ? 0 : warn_conversion;
 
+  /* -Wpacked-bitfield-compat is on by default for the C languages.  The
+     warning is issued in stor-layout.c which is not part of the front-end so
+     we need to selectively turn it on here.  */
+  if (warn_packed_bitfield_compat == -1)
+    warn_packed_bitfield_compat = 1;
 
   /* Special format checking options don't work without -Wformat; warn if
      they are used.  */

gcc/c.opt

@@ -365,7 +365,7 @@ C ObjC Var(warn_override_init) Init(-1) Warning
 Warn about overriding initializers without side effects
 
 Wpacked-bitfield-compat
-C ObjC C++ ObjC++ Var(warn_packed_bitfield_compat) Init(1) Warning
+C ObjC C++ ObjC++ Var(warn_packed_bitfield_compat) Init(-1) Warning
 Warn about packed bit-fields whose offset changed in GCC 4.4
 
 Wparentheses

gcc/stor-layout.c

@@ -963,7 +963,7 @@ place_field (record_layout_info rli, tree field)
 	{
 	  if (DECL_PACKED (field))
 	    {
-	      if (warn_packed_bitfield_compat)
+	      if (warn_packed_bitfield_compat == 1)
 		inform
 		  (input_location,
 		   "Offset of packed bit-field %qD has changed in GCC 4.4",