http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48702
--- Comment #15 from rakdver at kam dot mff.cuni.cz <rakdver at kam dot
mff.cuni.cz> 2011-05-17 19:26:18 UTC ---
Hi,
> The following patch fixes the problem. Is it ok?
as a heuristic, this probably makes sense. Still, it does
not fix the problem, just masks it and makes it harder to reproduce,
Zdenek
> David
>
>
> --- tree-ssa-loop-ivopts.c (revision 173278)
> +++ tree-ssa-loop-ivopts.c (working copy)
> @@ -3968,7 +3968,7 @@ get_computation_cost_at (struct ivopts_d
> int *inv_expr_id)
> {
> tree ubase = use->iv->base, ustep = use->iv->step;
> - tree cbase, cstep;
> + tree cbase, cstep, cbase_strip;
> tree utype = TREE_TYPE (ubase), ctype;
> unsigned HOST_WIDE_INT cstepi, offset = 0;
> HOST_WIDE_INT ratio, aratio;
> @@ -4026,6 +4026,13 @@ get_computation_cost_at (struct ivopts_d
> if (!constant_multiple_of (ustep, cstep, &rat))
> return infinite_cost;
>
> + cbase_strip = STRIP_NOPS (cbase);
> + /* Avoid confusing aliaser. */
> + if (TREE_CODE (cbase_strip) == ADDR_EXPR
> + && TREE_CODE (TREE_OPERAND (cbase_strip, 0)) == VAR_DECL
> + && (HOST_WIDE_INT) cstepi < 0)
> + return infinite_cost;
> +
> if (double_int_fits_in_shwi_p (rat))
> ratio = double_int_to_shwi (rat);
> else
>
> --
> Configure bugmail: http://gcc.gnu.org/bugzilla/userprefs.cgi?tab=email
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug.
