On Thu, Jun 14, 2012 at 4:39 AM, Kaz Kojima <kkoj...@rr.iij4u.or.jp> wrote:
> Oleg Endo <oleg.e...@t-online.de> wrote:
>> The attached patch improves code generated for byte swap expressions
>> such as ((x & 0xFF) << 8) | ((x >> 8) & 0xFF).
>> It seems that currently the tree optimizers only detect bswap32 and
>> bswap64 but not bswap16 patterns. The patch adds detection for bswap16
>> patterns by playing along with the combine pass.
>>
>> Tested with
>> make -k -j8 check RUNTESTFLAGS="--target_board=sh-sim
>> \{-m2/-ml,-m2/-mb,-m2a/-mb,-m2a-single/-mb,-m4/-ml,
>> -m4/-mb,-m4-single/-ml,-m4-single/-mb,-m4a-single/-ml,
>> -m4a-single/-mb}"
>>
>> and no new failures.
>> Test cases for this patch and the previous bswap32 patch will follow
>> shortly.
>
> The patch looks fine to me. OK for trunk.
>
> I guess that tree optimizers handle bswap32/64 with its cost
> because they are more frequent and critical in the real working
> set like network codes than bswap16, though I could be wrong
> about it.
I think the bswap16 builtin simply post-dates the bswap recognition code.
Richard.
> Regards,
> kaz
