http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52611
--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-03-19
10:53:23 UTC ---
(In reply to comment #4)
> I don't think we should drop a cast that changes a machine mode:
>
> --- tree-ssa.c.orig 2012-03-18 17:32:32.000000000 +0100
> +++ tree-ssa.c 2012-03-18 17:30:40.000000000 +0100
> @@ -1264,6 +1264,10 @@ useless_type_conversion_p (tree outer_ty
> if (POINTER_TYPE_P (inner_type)
> && POINTER_TYPE_P (outer_type))
> {
> + /* Do not lose casts between pointers in different machine modes. */
> + if (TYPE_MODE (inner_type) != TYPE_MODE (outer_type))
> + return false;
> +
> /* Do not lose casts between pointers to different address spaces. */
> if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type))
> != TYPE_ADDR_SPACE (TREE_TYPE (inner_type)))
>
> GCC 4.7 and GCC 4.8 have a similar check in place.
Yes, the patch that introduced this can/should be backported.
