[backport from gcc-4.7/trunk, fixes PR48031 on m68k <mikpe@it.uu.se>]

gcc/

2011-03-15  Richard Guenther  <rguenther@suse.de>

	PR middle-end/48031
	* fold-const.c (fold_indirect_ref_1): Do not create new variable-sized
	or variable-indexed array accesses when in gimple form.

--- gcc-4.6-20110312/gcc/fold-const.c.~1~	2011-03-08 11:43:10.000000000 +0100
+++ gcc-4.6-20110312/gcc/fold-const.c	2011-03-16 15:08:43.000000000 +0100
@@ -15554,12 +15554,17 @@ fold_indirect_ref_1 (location_t loc, tre
 	}
       /* *(foo *)&fooarray => fooarray[0] */
       else if (TREE_CODE (optype) == ARRAY_TYPE
-	       && type == TREE_TYPE (optype))
+	       && type == TREE_TYPE (optype)
+	       && (!in_gimple_form
+		   || TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST))
 	{
 	  tree type_domain = TYPE_DOMAIN (optype);
 	  tree min_val = size_zero_node;
 	  if (type_domain && TYPE_MIN_VALUE (type_domain))
 	    min_val = TYPE_MIN_VALUE (type_domain);
+	  if (in_gimple_form
+	      && TREE_CODE (min_val) != INTEGER_CST)
+	    return NULL_TREE;
 	  return build4_loc (loc, ARRAY_REF, type, op, min_val,
 			     NULL_TREE, NULL_TREE);
 	}
@@ -15633,7 +15638,9 @@ fold_indirect_ref_1 (location_t loc, tre
 
   /* *(foo *)fooarrptr => (*fooarrptr)[0] */
   if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE
-      && type == TREE_TYPE (TREE_TYPE (subtype)))
+      && type == TREE_TYPE (TREE_TYPE (subtype))
+      && (!in_gimple_form
+	  || TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST))
     {
       tree type_domain;
       tree min_val = size_zero_node;
@@ -15641,6 +15648,9 @@ fold_indirect_ref_1 (location_t loc, tre
       type_domain = TYPE_DOMAIN (TREE_TYPE (sub));
       if (type_domain && TYPE_MIN_VALUE (type_domain))
 	min_val = TYPE_MIN_VALUE (type_domain);
+      if (in_gimple_form
+	  && TREE_CODE (min_val) != INTEGER_CST)
+	return NULL_TREE;
       return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE,
 			 NULL_TREE);
     }