[MIPS, committed] Backport bswap patches to 4.8

[Richard Sandiford]

Richard Biener <richard.guenther@gmail.com> writes:
> On Thu, Jan 9, 2014 at 9:06 PM, Richard Sandiford
> <rdsandiford@googlemail.com> wrote:
>> I got an off-list request to backport the bswap patterns to 4.8.
>> They've been in trunk for a while without any problems being reported
>> and they should be relatively safe.
>>
>> Here's what I applied after testing on mips64-linux-gnu (with
>> --with-arch=mips64r2).  The only difference is the use of:
>>
>>   [(set_attr "length" "8")]
>>
>> rather than trunk's:
>>
>>   [(set_attr "insn_count" "2")]
>
> FYI, just a clarification from a RM perspective - it's ok for target maintainers
> to backport patches like this to the newest maintained release given they
> only touch target specific code (even if they are not regressions).  We've
> always had the policy to allow HW enablement on release branches and
> the target maintainers decide whether it's safe and non-intrusive enough.

OK, thanks.  That's how I thought it worked and was why I didn't ask
explicitly.  Hope I didn't rock the boat here.  (Sounds like there might
have been an IRC discussion or something. :-))

I assumed the patch I just applied to add extra cases to the
/proc/cpuinfo detection for Loongson came under the same category.
I put that one in 4.7 too because it should be ultra safe and because
it's a host thing rather than a target thing (someone upgrading their
kernel might otherwise find that gcc suddenly changes behaviour).

Thanks,
Richard