From: Thomas Koenig <tkoenig@netcologne.de>
To: Jakub Jelinek <jakub@redhat.com>, Bill Schmidt <wschmidt@linux.ibm.com>
Cc: fortran@gcc.gnu.org, gcc@gcc.gnu.org,
Tobias Burnus <tobias@codesourcery.com>,
Segher Boessenkool <segher@kernel.crashing.org>,
Michael Meissner <meissner@linux.ibm.com>
Subject: Re: libgfortran.so SONAME and powerpc64le-linux ABI changes
Date: Fri, 15 Oct 2021 20:05:38 +0200 [thread overview]
Message-ID: <4c0d1a0d-457f-68d7-94f3-420bc2c33c69@netcologne.de> (raw)
In-Reply-To: <20211015142049.GD304296@tucnak>
On 15.10.21 16:20, Jakub Jelinek wrote:
[...]
> when one compiles
> integer function foo ()
> foo = precision (0.0_16)
> end function foo
> integer function bar ()
> bar = range (0.0_16)
> end function bar
> with -mabi=ibmlongdouble, I see 31 and 291, while with -mabi=ieeelongdouble
> 33 and 4931. The 0.0_8 precision/range values are 15 and 307, so neither
> precision of C long double if it is double-double nor range matches anything.
> If we do implement double-double support, I think KIND=15 would be better
> than KIND=17, it is true that double-double has for certain numbers much
> higher precision than IEEE quad, but the precision depends on the numbers
> and most of the time is smaller, the range is always smaller. And
> the PRECISION/RANGE intrinsic numbers are also both smaller.
There is one potential problem: selected_real_kind.
The standard says about that...
# If more than one kind type parameter value meets the criteria, the
# value returned is the one with the smallest decimal precision, unless
# there are several such values, in which case the smallest of these
# kind values is returned
So, selected_real_kind(25) would yield double double, and we would
have to violate the standard there if we wanted people to have
IEEE QP in that case.
Best regards
Thomas
next prev parent reply other threads:[~2021-10-15 18:05 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 10:07 Jakub Jelinek
2021-10-04 11:24 ` Richard Biener
2021-10-04 11:36 ` Jakub Jelinek
2021-10-04 12:31 ` Jakub Jelinek
2021-10-04 14:14 ` Jakub Jelinek
2021-10-04 16:47 ` Joseph Myers
2021-10-04 18:33 ` Segher Boessenkool
2021-10-04 19:24 ` Joseph Myers
2021-10-05 17:43 ` Segher Boessenkool
2021-10-14 19:39 ` Bill Schmidt
2021-10-15 0:26 ` Segher Boessenkool
2021-10-05 20:16 ` Thomas Koenig
2021-10-05 21:54 ` Segher Boessenkool
2021-10-06 6:59 ` Thomas Koenig
2021-10-06 15:17 ` Segher Boessenkool
2021-10-06 15:41 ` Jakub Jelinek
2021-10-06 16:07 ` Segher Boessenkool
2021-10-06 16:34 ` Jakub Jelinek
2021-10-06 16:59 ` Segher Boessenkool
2021-10-06 17:07 ` Jakub Jelinek
2021-10-06 17:50 ` Segher Boessenkool
2021-10-06 19:30 ` Peter Bergner
2021-10-06 17:13 ` Joseph Myers
2021-10-06 18:39 ` Segher Boessenkool
2021-10-06 19:42 ` Joseph Myers
2021-10-06 20:57 ` Segher Boessenkool
2021-10-06 21:55 ` Joseph Myers
2021-10-06 22:03 ` Joseph Myers
2021-10-08 17:53 ` Segher Boessenkool
2021-10-11 20:11 ` Joseph Myers
2021-10-15 0:16 ` Segher Boessenkool
2021-10-06 15:42 ` David Edelsohn
2021-10-06 16:19 ` Segher Boessenkool
2021-10-06 17:38 ` David Edelsohn
2021-10-07 3:42 ` Michael Meissner
2021-10-08 21:10 ` Segher Boessenkool
2021-10-07 9:48 ` Alastair McKinstry
2021-10-07 9:56 ` Andreas Schwab
2021-10-07 10:01 ` Jakub Jelinek
2021-10-07 12:43 ` Alastair McKinstry
2021-10-05 21:53 ` Jonathan Wakely
2021-10-07 3:35 ` Michael Meissner
2021-10-07 6:08 ` Thomas Koenig
2021-10-07 9:40 ` Jakub Jelinek
2021-10-07 15:24 ` Michael Meissner
2021-10-07 15:33 ` Jakub Jelinek
2021-10-08 6:35 ` Thomas Koenig
2021-10-08 7:20 ` Iain Sandoe
2021-10-08 16:26 ` Thomas Koenig
2021-10-08 19:11 ` Iain Sandoe
2021-10-08 22:55 ` Thomas Koenig
2021-10-08 23:18 ` Iain Sandoe
2021-10-09 9:11 ` Thomas Koenig
2021-10-09 9:19 ` Iain Sandoe
2021-10-09 9:25 ` Jakub Jelinek
2021-10-09 7:44 ` Andreas Schwab
2021-10-10 16:14 ` Florian Weimer
2021-10-15 13:50 ` Bill Schmidt
2021-10-15 14:20 ` Jakub Jelinek
2021-10-15 18:05 ` Thomas Koenig [this message]
2021-10-15 18:11 ` Jakub Jelinek
2021-10-15 18:58 ` Thomas Koenig
2021-10-15 22:24 ` Segher Boessenkool
2021-10-15 22:36 ` Segher Boessenkool
2021-10-18 19:02 ` Joseph Myers
2021-10-28 3:10 ` Michael Meissner
2021-10-29 3:36 ` libgfortran.so SONAME and powerpc64le-linux ABI changes (work in progress patches) Michael Meissner
2021-10-29 19:07 ` Thomas Koenig
2021-10-29 21:06 ` Michael Meissner
2021-11-01 15:56 ` Bill Schmidt
2021-11-02 15:40 ` Michael Meissner
2021-10-30 0:16 ` libgfortran.so SONAME and powerpc64le-linux ABI changes (2nd patch) Michael Meissner
2021-10-30 9:30 ` Thomas Koenig
2021-10-30 10:03 ` Jakub Jelinek
2021-10-30 10:31 ` Thomas Koenig
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