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From: "jacob at jacob dot remcomp.fr" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/107370] long double precision is wrong in ARM 64
Date: Mon, 24 Oct 2022 06:22:53 +0000	[thread overview]
Message-ID: <bug-107370-4-KlUf8p5snN@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107370-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107370

--- Comment #1 from jacob navia <jacob at jacob dot remcomp.fr> ---
This program produces correct results:
#include <stdio.h>
#include <math.h>
long double nsqrt(long double x)
{
        double m = sqrt(x);
        long double r = m;

        r = (r+x/r)/2.0L;

        r = (r+x/r)/2.0L;
        r = (r+x/r)/2.0L;
        r = (r+x/r)/2.0L;
        r = (r+x/r)/2.0L;
        return r;
}

int main(void) { printf("%.30Lg \n",nsqrt(2.0L)); }
produces:
1.41421356237309504880168872421 
All digits que OK.

jacob

  reply	other threads:[~2022-10-24  6:22 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-24  6:11 [Bug c/107370] New: " jacob at jacob dot remcomp.fr
2022-10-24  6:22 ` jacob at jacob dot remcomp.fr [this message]
2022-10-24 15:19 ` [Bug target/107370] " pinskia at gcc dot gnu.org
2022-10-24 18:33 ` jacob at jacob dot remcomp.fr
2022-10-24 18:40 ` [Bug middle-end/107370] long double sqrtl constant folding is wrong pinskia at gcc dot gnu.org
2022-10-24 19:27 ` jakub at gcc dot gnu.org
2022-10-24 19:53 ` jacob at jacob dot remcomp.fr
2022-10-24 19:56 ` jacob at jacob dot remcomp.fr
2022-10-24 20:00 ` joseph at codesourcery dot com
2022-10-24 20:01 ` jacob at jacob dot remcomp.fr
2022-10-24 20:08 ` jacob at jacob dot remcomp.fr
2022-10-24 20:09 ` jacob at jacob dot remcomp.fr
2022-10-24 20:21 ` jakub at gcc dot gnu.org
2022-10-24 20:25 ` jakub at gcc dot gnu.org
2022-10-24 20:32 ` jakub at gcc dot gnu.org
2022-10-24 20:50 ` jacob at jacob dot remcomp.fr
2022-10-24 20:51 ` jacob at jacob dot remcomp.fr
2022-10-24 20:56 ` jacob at jacob dot remcomp.fr
2022-10-24 20:59 ` jacob at jacob dot remcomp.fr
2022-10-24 21:01 ` jacob at jacob dot remcomp.fr
2022-10-24 21:02 ` jakub at gcc dot gnu.org
2022-10-24 21:03 ` jacob at jacob dot remcomp.fr
2022-10-24 21:06 ` jacob at jacob dot remcomp.fr
2022-10-24 21:09 ` jakub at gcc dot gnu.org
2022-10-24 21:26 ` jacob at jacob dot remcomp.fr
2022-10-24 21:29 ` pinskia at gcc dot gnu.org
2022-10-24 21:31 ` pinskia at gcc dot gnu.org

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