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From: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/101918] LTO type mismatches for runtime library functions in mixed -fdefault-real-8 projects
Date: Mon, 30 Aug 2021 14:48:24 +0000	[thread overview]
Message-ID: <bug-101918-4-VqnaItDIa9@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-101918-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101918

--- Comment #11 from kargl at gcc dot gnu.org ---
(In reply to Rimvydas (RJ) from comment #7)
At least some common examples of what to look for in
> documentation about "gfortran -fdefault-real-8 -fdefault-double-8"
> limitations (if these options are really that broken) would be very
> appreciated by the software porters :)

% cat foo.f90
program foo
   x = 1.
   y = 3.14159
   a = 1._4
   b = 3.14159_4
   print *, a / b
   print *, x/ y
end program foo
% gfcx -o z a.f90 && ./z
  0.318310142    
  0.318310142    
% gfcx -o z -fdefault-real-8 a.f90 && ./z
  0.31831014305159744     
  0.31831015504887655     
% gfcx -o z -freal-4-real-8 a.f90 && ./z
  0.31831015504887655     
  0.31831015504887655     

One of these is no like the others. Yes, the behavior is documented,
and the unlike other result is likely the result that is no desired
unless the user enjoys chancing numerical precision issues.

  parent reply	other threads:[~2021-08-30 14:48 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-15  8:41 [Bug fortran/101918] New: " rimvydas.jas at gmail dot com
2021-08-15  8:42 ` [Bug fortran/101918] " rimvydas.jas at gmail dot com
2021-08-15 15:36 ` kargl at gcc dot gnu.org
2021-08-16  9:15 ` rguenth at gcc dot gnu.org
2021-08-16 14:57 ` sgk at troutmask dot apl.washington.edu
2021-08-16 18:49 ` anlauf at gcc dot gnu.org
2021-08-16 21:34 ` sgk at troutmask dot apl.washington.edu
2021-08-30 10:26 ` rimvydas.jas at gmail dot com
2021-08-30 10:28 ` rimvydas.jas at gmail dot com
2021-08-30 14:34 ` sgk at troutmask dot apl.washington.edu
2021-08-30 14:39 ` kargl at gcc dot gnu.org
2021-08-30 14:48 ` kargl at gcc dot gnu.org [this message]
2021-08-30 15:23 ` rimvydas.jas at gmail dot com
2021-08-30 16:16 ` sgk at troutmask dot apl.washington.edu
2021-08-30 17:11 ` rimvydas.jas at gmail dot com
2021-08-30 18:26 ` sgk at troutmask dot apl.washington.edu
2021-08-30 19:08 ` rimvydas.jas at gmail dot com
2021-08-30 20:54 ` sgk at troutmask dot apl.washington.edu
2021-08-30 21:23 ` rimvydas.jas at gmail dot com
2021-08-30 22:18 ` sgk at troutmask dot apl.washington.edu
2021-08-30 22:26 ` rimvydas.jas at gmail dot com
2021-09-02 11:01 ` rimvydas.jas at gmail dot com
2021-09-02 11:02 ` rimvydas.jas at gmail dot com
2021-09-02 11:05 ` rimvydas.jas at gmail dot com
2021-09-02 11:06 ` rimvydas.jas at gmail dot com
2021-09-02 11:08 ` rimvydas.jas at gmail dot com
2021-09-12 19:12 ` rimvydas.jas at gmail dot com

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