https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83253
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Bill Schmidt from comment #5)
> Here's an untested patch (bootstraps successfully but regtest is still
> ongoing):
>
> Index: gcc/gimple-ssa-strength-reduction.c
>
> ===================================================================
> --- gcc/gimple-ssa-strength-reduction.c (revision 255588)
>
> +++ gcc/gimple-ssa-strength-reduction.c (working copy)
>
> @@ -3083,7 +3083,17 @@ analyze_increments (slsr_cand_t first_dep, machine
> else if (first_dep->kind == CAND_MULT)
>
> {
>
> int cost = mult_by_coeff_cost (incr, mode, speed);
>
> - int repl_savings = mul_cost (speed, mode) - add_cost (speed,
> mode);
> + int repl_savings;
>
> +
>
> + if (TREE_CODE (first_dep->stride) == INTEGER_CST)
Please use if (tree_fits_shwi_p (first_dep->stride)) instead, otherwise
tree_to_shwi will ICE if some stride is outside of the shwi range.
>
> + {
>
> + HOST_WIDE_INT hwi_stride = tree_to_shwi (first_dep->stride);
>
> + repl_savings = (mult_by_coeff_cost (hwi_stride, mode, speed)
>
> + - add_cost (speed, mode));
>
> + }
>
> + else
>
> + repl_savings = mul_cost (speed, mode) - add_cost (speed, mode);
Also, I think it might be better to move the - add_cost (speed, mode)
part outside of the conditional, i.e. set either repl_savings or some other
temporary just to mult_by_coeff_cost or mul_cost and then compute repl_saving
by subtracting that and add_cost.
