------- Comment #8 from manu at gcc dot gnu dot org 2008-11-01 17:44 -------
This is my current patch and it works in this testcase. However, it also
triggers on cases like: const char *p = str + sizeof(str)
Perhaps I am doing this at the wrong place. Any suggestions?
@@ -3322,10 +3323,36 @@ pointer_int_sum (enum tree_code resultco
/* Create the sum or difference. */
if (resultcode == MINUS_EXPR)
intop = fold_build1 (NEGATE_EXPR, sizetype, intop);
+
+ if (TREE_CODE (intop) == INTEGER_CST)
+ {
+ tree offset_node;
+ tree string_cst = string_constant (ptrop, &offset_node);
+
+ if (string_cst != 0
+ && !(offset_node && TREE_CODE (offset_node) != INTEGER_CST))
+ {
+ HOST_WIDE_INT max = TREE_STRING_LENGTH (string_cst) - 1;
+ HOST_WIDE_INT offset;
+ if (offset_node == 0)
+ offset = 0;
+ else if (! host_integerp (offset_node, 0))
+ offset = -1;
+ else
+ offset = tree_low_cst (offset_node, 0);
+
+ offset = offset + tree_low_cst (intop, 0);
+ if (offset < 0 || offset > max)
+ warning_at (location, 0,
+ "offset %<%ld%> outside bounds of constant string",
+ tree_low_cst (intop, 0));
+ }
+ }
+
ret = fold_build2 (POINTER_PLUS_EXPR, result_type, ptrop, intop);
fold_undefer_and_ignore_overflow_warnings ();
return ret;
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35652
