Re: [POC] verifying UTF-8 using SIMD instructions

On Tue, Mar 9, 2021 at 5:00 AM Amit Khandekar <amitdkhan.pg@gmail.com>
wrote:
>
> Hi,
>
> Just a quick question before I move on to review the patch ... The
> improvement looks like it is only meant for x86 platforms.

Actually it's meant to be faster for all platforms, since the C fallback is
quite a bit different from HEAD. I've found it to be faster on ppc64le. An
earlier version of the patch was a loser on 32-bit Arm because of alignment
issues, but if you could run the test script attached to [1] on 64-bit Arm,
I'd be curious to see how it does on 0002, and whether 0003 and 0004 make
things better or worse. If there is trouble building on non-x86 platforms,
I'd want to fix that also.

(Note: 0001 is not my patch, and I just include it for the tests)

> Can this be
> done in a portable way by arranging for auto-vectorization ? Something
> like commit 88709176236caf. This way it would benefit other platforms
> as well.

I'm fairly certain that the author of a compiler capable of doing that in
this case would be eligible for some kind of AI prize. :-)

[1]
https://www.postgresql.org/message-id/06d45421-61b8-86dd-e765-f1ce527a5a2f@iki.fi
--
John Naylor
EDB: http://www.enterprisedb.com