[PATCH] Fix simplify_builtin_call forwprop ICE (PR tree-optimization/64269)

[Jakub Jelinek]

Hi!

This testcase ICEs because I wasn't checking for overflow in the size
computation.  Only max (diff + len2, len1) <= 1024 cases are considered,
so this patch gives up if either len2 or diff is > 1024.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.9/4.8?

2014-12-12  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/64269
        * tree-ssa-forwprop.c (simplify_builtin_call): Bail out if
        len2 or diff are too large.

        * gcc.c-torture/compile/pr64269.c: New test.

--- gcc/tree-ssa-forwprop.c.jj  2014-12-01 14:57:30.000000000 +0100
+++ gcc/tree-ssa-forwprop.c     2014-12-12 09:46:05.790053928 +0100
@@ -1288,7 +1288,8 @@ simplify_builtin_call (gimple_stmt_itera
          use_operand_p use_p;
 
          if (!tree_fits_shwi_p (val2)
-             || !tree_fits_uhwi_p (len2))
+             || !tree_fits_uhwi_p (len2)
+             || compare_tree_int (len2, 1024) == 1)
            break;
          if (is_gimple_call (stmt1))
            {
@@ -1354,7 +1355,8 @@ simplify_builtin_call (gimple_stmt_itera
             is not constant, or is bigger than memcpy length, bail out.  */
          if (diff == NULL
              || !tree_fits_uhwi_p (diff)
-             || tree_int_cst_lt (len1, diff))
+             || tree_int_cst_lt (len1, diff)
+             || compare_tree_int (diff, 1024) == 1)
            break;
 
          /* Use maximum of difference plus memset length and memcpy length
--- gcc/testsuite/gcc.c-torture/compile/pr64269.c.jj    2014-12-12 
09:47:04.795015479 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr64269.c       2014-12-12 
09:46:51.000000000 +0100
@@ -0,0 +1,9 @@
+/* PR tree-optimization/64269 */
+
+void
+foo (char *p)
+{
+  __SIZE_TYPE__ s = ~(__SIZE_TYPE__)0;
+  *p = 0;
+  __builtin_memset (p + 1, 0, s);
+}

        Jakub