re PR c/22371 (C front-end produces mis-match types in MODIFY_EXPR)

2008-03-24  Richard Guenther  <rguenther@suse.de>

	PR c/22371
	* gimplify.c (gimplify_modify_expr): For frontend type-correct
	pointer assignments change conversions according to middle-end rules.
	(gimplify_modify_expr_rhs): Deal with NULL TARGET_EXPR_INITIAL.
	* configure.ac: Include type checking in yes.
	* configure: Regenerate.

From-SVN: r133479

gcc/ChangeLog

+2008-03-24  Richard Guenther  <rguenther@suse.de>
+
+	PR c/22371
+	* gimplify.c (gimplify_modify_expr): For frontend type-correct
+	pointer assignments change conversions according to middle-end rules.
+	(gimplify_modify_expr_rhs): Deal with NULL TARGET_EXPR_INITIAL.
+	* configure.ac: Include type checking in yes.
+	* configure: Regenerate.
+
 2008-03-24  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
 	* diagnostic.c (diagnostic_count_diagnostic): Delete.

gcc/configure

@@ -6439,7 +6439,7 @@ do
 			ac_gc_always_collect= ; ac_rtl_checking= ;
 			ac_rtlflag_checking=1 ; ac_runtime_checking=1 ;
 			ac_tree_checking=1 ; ac_valgrind_checking= ;
-			ac_types_checking= ;;
+			ac_types_checking=1 ;;
 	no|none)	ac_assert_checking= ; ac_checking= ; ac_df_checking= ;
 			ac_fold_checking= ; ac_gc_checking= ;
 			ac_gc_always_collect= ; ac_rtl_checking= ;

gcc/configure.ac

@@ -367,7 +367,7 @@ do
 			ac_gc_always_collect= ; ac_rtl_checking= ;
 			ac_rtlflag_checking=1 ; ac_runtime_checking=1 ;
 			ac_tree_checking=1 ; ac_valgrind_checking= ;
-			ac_types_checking= ;;
+			ac_types_checking=1 ;;
 	no|none)	ac_assert_checking= ; ac_checking= ; ac_df_checking= ;
 			ac_fold_checking= ; ac_gc_checking= ;
 			ac_gc_always_collect= ; ac_rtl_checking= ;

gcc/gimplify.c

@@ -3599,7 +3599,8 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p,
 	     references somehow.  */
 	  tree init = TARGET_EXPR_INITIAL (*from_p);
 
-	  if (!VOID_TYPE_P (TREE_TYPE (init)))
+	  if (init
+	      && !VOID_TYPE_P (TREE_TYPE (init)))
 	    {
 	      *from_p = init;
 	      ret = GS_OK;
@@ -3870,6 +3871,17 @@ gimplify_modify_expr (tree *expr_p, tree *pre_p, tree *post_p, bool want_value)
 	      || TREE_CODE (*expr_p) == GIMPLE_MODIFY_STMT
 	      || TREE_CODE (*expr_p) == INIT_EXPR);
 
+  /* Insert pointer conversions required by the middle-end that are not
+     required by the frontend.  This fixes middle-end type checking for
+     for example gcc.dg/redecl-6.c.  */
+  if (POINTER_TYPE_P (TREE_TYPE (*to_p))
+      && lang_hooks.types_compatible_p (TREE_TYPE (*to_p), TREE_TYPE (*from_p)))
+    {
+      STRIP_USELESS_TYPE_CONVERSION (*from_p);
+      if (!useless_type_conversion_p (TREE_TYPE (*to_p), TREE_TYPE (*from_p)))
+	*from_p = fold_convert (TREE_TYPE (*to_p), *from_p);
+    }
+
   /* See if any simplifications can be done based on what the RHS is.  */
   ret = gimplify_modify_expr_rhs (expr_p, from_p, to_p, pre_p, post_p,
 				  want_value);