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

Amit Khandekar <amitdkhan.pg@gmail.com>

From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2021-03-09T09:00:21Z
Lists: pgsql-hackers
Hi,

Just a quick question before I move on to review the patch ... The
improvement looks like it is only meant for x86 platforms. 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 tried to compile the following code using -O3, and the assembly does
have vectorized instructions.

#include <stdio.h>
int main()
{
        int i;
        char s1[200] = "abcdewhruerhetr";
        char s2[200] = "oweurietiureuhtrethre";
        char s3[200] = {0};

    for (i = 0; i < sizeof(s1); i++)
    {
        s3[i] = s1[i] ^ s2[i];
    }

    printf("%s\n", s3);
}



Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Simplify coding style of is_valid_ascii()

  2. Apply auto-vectorization to the inner loop of numeric multiplication.