[PATCH] i586: Use a jump table in strcpy.S {BZ #22353]

[H.J. Lu]

On Mon, Oct 30, 2017 at 4:18 AM, Florian Weimer <fweimer@redhat.com> wrote:
> On 10/27/2017 11:07 PM, H.J. Lu wrote:
>>
>> This may fail if there are instruction changes before L(1):.  This patch
>> replaces it with a jump table which works with any instruction changes.
>
>
> I think you should say instruction *length* changes.

Done.  The updated patch is at

https://sourceware.org/git/?p=glibc.git;a=patch;h=9a89973274f901f4c3313e6e2b84d6b2108c7924

> What's the performance impact of the change?  Is it even worth to use a jump
> table here?
>

I added 2 strcpy implementations to hjl/pr22353/master.  Jump table is faster
than other non-SSE strcpy implementations because it can copy up to 4 bytes
at a time.


-- 
H.J.