Re: [PATCH] Changes in mode switching

[Vladimir Yakovlev <vbyakovl23 at gmail dot com>]

Thank you for testing.

> With commenting out "if (i != mode)" of the hunk

I changed type of transp and added this checking because if we reset
transp[mode], then later in the loop

      FOR_EACH_BB (bb)
        sbitmap_not (kill[bb->index], transp[i][bb->index]);

we set kill of the bb for that mode and thereby force insertion mode
switching for the mode in succeeding blocks in any case.

Regards,
Vladimir

2012/8/24 Kaz Kojima <kkojima@rr.iij4u.or.jp>:
>> I've tried the patch on sh4-unknown-linux-gnu.  I see new failures
>> with it:
>
> Here is a reduced test case for sh4-unknown-linux-gnu.
>
> volatile double gd[32];
> volatile float gf[32];
>
> int main ()
> {
>   int i;
>
>   for (i = 0; i < 32; i++)
>     gd[i] = i * 4, gf[i] = i;
>
>   for (i = 0; i < 32; i++)
>     if (gd[i] != i * 4
>         || gf[i] != i)
>       abort ();
>   exit (0);
> }
>
> The problem occurs at the second loop.  With the patch, the only
> mode switching is done at just before gf[i] != i.
> OTOH the original compiler inserts mode switchings both at before
> gd[i] != i * 4 and gf[i] != i.
> With commenting out "if (i != mode)" of the hunk
>
> @@ -530,10 +535,16 @@ optimize_mode_switching (void)
>                       last_mode = mode;
>                       ptr = new_seginfo (mode, insn, bb->index, live_now);
>                       add_seginfo (info + bb->index, ptr);
> -                     RESET_BIT (transp[bb->index], j);
> +                     for (i = 0 ; i < max_num_modes; i++)
> +                       if (i != mode)
> +                         RESET_BIT (transp[i][bb->index], j);
> ...
>
> it looks all new failures go away.
>
> Regards,
>         kaz