Hi!
On Thu, Oct 08, 2020 at 09:27:55AM +1030, Alan Modra wrote:
> * config/rs6000/rs6000.c (rs6000_rtx_costs): Tidy AND code.
> Don't avoid recursion on const_int shift count.
>
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index e870ba0039a..bc5e51aa5ce 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -21253,6 +21253,7 @@ static bool
> rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code,
> int opno ATTRIBUTE_UNUSED, int *total, bool speed)
> {
> + rtx right;
Please declare things where you first use them.
> int code = GET_CODE (x);
>
> switch (code)
> @@ -21430,7 +21431,9 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int
> outer_code,
> return false;
>
> case AND:
> - if (CONST_INT_P (XEXP (x, 1)))
> + *total = COSTS_N_INSNS (1);
> + right = XEXP (x, 1);
> + if (CONST_INT_P (right))
> {
> rtx left = XEXP (x, 0);
> rtx_code left_code = GET_CODE (left);
> @@ -21439,17 +21442,13 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int
> outer_code,
> if ((left_code == ROTATE
> || left_code == ASHIFT
> || left_code == LSHIFTRT)
> - && rs6000_is_valid_shift_mask (XEXP (x, 1), left, mode))
> + && rs6000_is_valid_shift_mask (right, left, mode))
You could have left all this intact, it is just distraction from the
rest of the patch (nothing changed here). Except you set *total.
> {
> - *total = rtx_cost (XEXP (left, 0), mode, left_code, 0, speed);
> - if (!CONST_INT_P (XEXP (left, 1)))
> - *total += rtx_cost (XEXP (left, 1), SImode, left_code, 1,
> speed);
> - *total += COSTS_N_INSNS (1);
> + *total += rtx_cost (XEXP (left, 0), mode, left_code, 0, speed);
> + *total += rtx_cost (XEXP (left, 1), SImode, left_code, 1, speed);
> return true;
> }
> }
> -
> - *total = COSTS_N_INSNS (1);
> return false;
I still do not see what this improves, I only see possible obvious
regressions :-(
Segher
