[PATCH] Fix PR middle-end/66984 - mis-optimization of CEIL_DIV_EXPR and FLOOR_DIV_EXPR

[Gary Funck]

See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66984

Confirmed that GCC trunk bootstraps without issue and
that this patch fixes the issue noted in the GUPC branch.

2015-07-24  Gary Funck  <g...@intrepid.com>

        PR middle-end/66984
        * fold-const.c (fold_binary_loc): Call fold_convert on arguments to
        fold_build2 for CEIL_DIV_EXPR and FLOOR_DIV_EXPR optimization.

Index: fold-const.c
===================================================================
--- fold-const.c        (revision 226135)
+++ fold-const.c        (working copy)
@@ -10804,7 +10804,9 @@ fold_binary_loc (location_t loc,
         after the last round to changes to the DIV code in expmed.c.  */
       if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
          && multiple_of_p (type, arg0, arg1))
-       return fold_build2_loc (loc, EXACT_DIV_EXPR, type, arg0, arg1);
+       return fold_build2_loc (loc, EXACT_DIV_EXPR, type,
+                               fold_convert (type, arg0),
+                               fold_convert (type, arg1));
 
       strict_overflow_p = false;
       if (TREE_CODE (arg1) == INTEGER_CST