Missed part of my patch:

        * langhooks-def.h (lhd_decl_uninit): Declare.
        (LANG_HOOKS_DECL_UNINIT): New macro.
        (LANG_HOOKS_INITIALIZER): Adjust.
        * langhooks.h (struct lang_hooks): Add new field
        decl_uninit.
        * langhooks.c (lhd_decl_uninit): Define.

From-SVN: r70580

gcc/langhooks-def.h

@@ -63,6 +63,7 @@ extern void lhd_incomplete_type_error (tree, tree);
 extern tree lhd_type_promotes_to (tree);
 extern bool lhd_decl_ok_for_sibcall (tree);
 extern tree lhd_expr_size (tree);
+extern bool lhd_decl_uninit (tree);
 extern size_t lhd_tree_size (enum tree_code);
 
 /* Declarations of default tree inlining hooks.  */
@@ -114,6 +115,7 @@ extern void lhd_initialize_diagnostics (struct diagnostic_context *);
 #define LANG_HOOKS_PRINT_ERROR_FUNCTION lhd_print_error_function
 #define LANG_HOOKS_DECL_PRINTABLE_NAME	lhd_decl_printable_name
 #define LANG_HOOKS_EXPR_SIZE		lhd_expr_size
+#define LANG_HOOKS_DECL_UNINIT		lhd_decl_uninit
 #define LANG_HOOKS_TREE_SIZE		lhd_tree_size
 
 #define LANG_HOOKS_FUNCTION_INIT	lhd_do_nothing_f
@@ -278,6 +280,7 @@ extern int lhd_tree_dump_type_quals (tree);
   LANG_HOOKS_DECL_PRINTABLE_NAME, \
   LANG_HOOKS_PRINT_ERROR_FUNCTION, \
   LANG_HOOKS_EXPR_SIZE, \
+  LANG_HOOKS_DECL_UNINIT, \
   LANG_HOOKS_ATTRIBUTE_TABLE, \
   LANG_HOOKS_COMMON_ATTRIBUTE_TABLE, \
   LANG_HOOKS_FORMAT_ATTRIBUTE_TABLE, \

gcc/langhooks.c

@@ -430,6 +430,14 @@ lhd_expr_size (tree exp)
   else
     return size_in_bytes (TREE_TYPE (exp));
 }
+/* lang_hooks.decl_uninit: Find out if a variable is uninitialized based
+   on DECL_INITIAL.  */
+
+bool
+lhd_decl_uninit (tree t ATTRIBUTE_UNUSED)
+{
+  return false;
+}
 
 /* lang_hooks.tree_size: Determine the size of a tree with code C,
    which is a language-specific tree code in category 'x'.  The

gcc/langhooks.h

@@ -361,6 +361,10 @@ struct lang_hooks
      semantics in cases that it doesn't want to handle specially.  */
   tree (*expr_size) (tree);
 
+  /* Called from uninitialized_vars_warning to find out if a variable is
+     uninitialized based on DECL_INITIAL. */
+  bool (*decl_uninit) (tree);
+
   /* Pointers to machine-independent attribute tables, for front ends
      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
      table of attributes specific to the language, a table of