Re: [PATCH, rs6000] Improve swap optimization to modify general xxpermdi patterns

[David Edelsohn <dje.gcc@gmail.com>]

On Sun, Aug 30, 2015 at 7:19 PM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> Hi,
>
> The VSX swap optimization currently misses opportunities to optimize
> loops when expressions corresponding to xxpermdi instructions are
> present (other than xxswapd instructions associated with loads and
> stores).  These occur commonly when interleaving vector double or vector
> unsigned long operands, or when concatenating two doubles or unsigned
> longs to make a V2DI or V2DF result.  This patch adds logic to recognize
> these insns and adjust them to account for swapped doublewords in the
> computation.
>
> Both opportunities arise in a simple test case that performs a reduction
> on complex multiplications, which I've added here.
>
> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no
> regressions.  Is this ok for trunk?
>
> Thanks,
> Bill
>
>
> [gcc]
>
> 2015-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * config/rs6000/rs6000.c (swap_web_entry): Enlarge
>         special_handling bitfield.
>         (special_handling_values): Add SH_XXPERMDI and SH_CONCAT.
>         (rtx_is_swappable_p): Add handling for vec_select/vec_concat
> form
>         that represents a general xxpermdi.
>         (insn_is_swappable_p): Add handling for vec_concat of two
>         doublewords, which maps to a specific xxpermdi.
>         (adjust_xxpermdi): New function.
>         (adjust_concat): Likewise.
>         (handle_special_swappables): Call adjust_xxpermdi and
>         adjust_concat.
>         (dump_swap_insn_table): Handle SH_XXPERMDI and SH_CONCAT.
>
> [gcc/testsuite]
>
> 2015-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * gcc.target/powerpc/swaps-p8-19.c: New test.

Okay.

Thanks, David