* [Bug fortran/30780] cpu_time produces a floating point exception when used with -O0
2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
@ 2007-02-12 21:26 ` pinskia at gcc dot gnu dot org
2007-02-12 21:28 ` pinskia at gcc dot gnu dot org
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From: pinskia at gcc dot gnu dot org @ 2007-02-12 21:26 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2007-02-12 21:25 -------
*** Bug 30781 has been marked as a duplicate of this bug. ***
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
2007-02-12 21:26 ` [Bug fortran/30780] " pinskia at gcc dot gnu dot org
@ 2007-02-12 21:28 ` pinskia at gcc dot gnu dot org
2007-02-13 4:26 ` kargl at gcc dot gnu dot org
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From: pinskia at gcc dot gnu dot org @ 2007-02-12 21:28 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from pinskia at gcc dot gnu dot org 2007-02-12 21:28 -------
This works for me on x86 linux-gnu.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
^ permalink raw reply [flat|nested] 13+ messages in thread* [Bug fortran/30780] cpu_time produces a floating point exception when used with -O0
2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
2007-02-12 21:26 ` [Bug fortran/30780] " pinskia at gcc dot gnu dot org
2007-02-12 21:28 ` pinskia at gcc dot gnu dot org
@ 2007-02-13 4:26 ` kargl at gcc dot gnu dot org
2007-02-13 4:32 ` [Bug libfortran/30780] " pinskia at gcc dot gnu dot org
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From: kargl at gcc dot gnu dot org @ 2007-02-13 4:26 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from kargl at gcc dot gnu dot org 2007-02-13 04:26 -------
troutmask:sgk[223] gfc4x -o z -g -ffpe-trap='precision' g.f90
troutmask:sgk[224] gdb ./z
(gdb) run
Starting program: /usr/home/sgk/tmp/z
Program received signal SIGFPE, Arithmetic exception.
0x000000000040a3b2 in *_gfortrani_cpu_time_4 (time=0x7fffffffe988)
at ../../../gcc4x/libgfortran/intrinsics/cpu_time.c:160
160 *time = sec + usec * (GFC_REAL_4)1.e-6;
I have no idea how to fix this problem at the moment.
This is on amd64-*-freebsd.
--
kargl at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2007-02-13 04:26:26
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
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2007-02-13 4:26 ` kargl at gcc dot gnu dot org
@ 2007-02-13 4:32 ` pinskia at gcc dot gnu dot org
2007-02-13 5:41 ` jvdelisle at gcc dot gnu dot org
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From: pinskia at gcc dot gnu dot org @ 2007-02-13 4:32 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from pinskia at gcc dot gnu dot org 2007-02-13 04:32 -------
I have no idea how to fix this problem at the moment.
It is hard as there are no functions which convert from a floating point to an
integer that might not raise a signal. This is why setting trapping on
precision is almost something you never want to do.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|fortran |libfortran
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
^ permalink raw reply [flat|nested] 13+ messages in thread* [Bug libfortran/30780] cpu_time produces a floating point exception when used with -O0
2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (3 preceding siblings ...)
2007-02-13 4:32 ` [Bug libfortran/30780] " pinskia at gcc dot gnu dot org
@ 2007-02-13 5:41 ` jvdelisle at gcc dot gnu dot org
2007-02-13 6:41 ` kargl at gcc dot gnu dot org
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From: jvdelisle at gcc dot gnu dot org @ 2007-02-13 5:41 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from jvdelisle at gcc dot gnu dot org 2007-02-13 05:41 -------
I modified cpu_time_4 to just return some dummy values, and experimented a bit
with the test case. When I commented out the print statement, the exception
went away.
Here is a reduced test case.
program test2
real :: dog
dog = 1.0
print *, dog
end program test2
The exception is occurring in the print statement. Nothing to do with time.
(gdb) r
Starting program: /home/jerry/prs/pr30780/a.out
Program received signal SIGFPE, Arithmetic exception.
0x00002aaaaab2c3d9 in write_float (dtp=0x7fff52698b00, f=0x7fff52698a50,
source=<value optimized out>, len=<value optimized out>)
at ../../../gcc43/libgfortran/io/write.c:366
366 if ((m > 0.0 && m < 0.1 - 0.05 / exp_d) || (m >= exp_d - 0.5 ) ||
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
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2007-02-13 5:41 ` jvdelisle at gcc dot gnu dot org
@ 2007-02-13 6:41 ` kargl at gcc dot gnu dot org
2007-02-14 0:37 ` jvdelisle at gcc dot gnu dot org
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From: kargl at gcc dot gnu dot org @ 2007-02-13 6:41 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from kargl at gcc dot gnu dot org 2007-02-13 06:41 -------
(In reply to comment #5)
> The exception is occurring in the print statement. Nothing to do with time.
>
No, there is a "problem" in cpu_time. -ffpe-trap='precision' is
trapping on lost precision. On x86_64, long is 64-bit and
GFC_REAL_4 is 32-bit with only 24-bits of precision. You can't
convert long to GFC_REAL_4 without loss of precision. In short,
using this option is probably not a good idea if you have mixed
mode math.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (5 preceding siblings ...)
2007-02-13 6:41 ` kargl at gcc dot gnu dot org
@ 2007-02-14 0:37 ` jvdelisle at gcc dot gnu dot org
2007-09-21 11:37 ` [Bug libfortran/30780] FPE in CPU_TIME (and possibly others) with -ffpe-trap=underflow fxcoudert at gcc dot gnu dot org
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From: jvdelisle at gcc dot gnu dot org @ 2007-02-14 0:37 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from jvdelisle at gcc dot gnu dot org 2007-02-14 00:37 -------
OK, then there is a similar, not necessarily related problem in write.c.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (6 preceding siblings ...)
2007-02-14 0:37 ` jvdelisle at gcc dot gnu dot org
@ 2007-09-21 11:37 ` fxcoudert at gcc dot gnu dot org
2007-09-21 11:45 ` burnus at gcc dot gnu dot org
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From: fxcoudert at gcc dot gnu dot org @ 2007-09-21 11:37 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from fxcoudert at gcc dot gnu dot org 2007-09-21 11:37 -------
I'm changing this into a documentation PR, and assign it to myself. It was
decided that there really isn't a good way to provide high-quality timer
functions with precision-loss trapping. We need to document this shortcoming in
the -ffpe-trap option doc.
--
fxcoudert at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |fxcoudert at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
GCC target triplet|x86_64-redhat-linux |
Keywords| |documentation
Last reconfirmed|2007-02-13 04:26:26 |2007-09-21 11:37:15
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (7 preceding siblings ...)
2007-09-21 11:37 ` [Bug libfortran/30780] FPE in CPU_TIME (and possibly others) with -ffpe-trap=underflow fxcoudert at gcc dot gnu dot org
@ 2007-09-21 11:45 ` burnus at gcc dot gnu dot org
2007-09-21 11:59 ` fxcoudert at gcc dot gnu dot org
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From: burnus at gcc dot gnu dot org @ 2007-09-21 11:45 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from burnus at gcc dot gnu dot org 2007-09-21 11:45 -------
> We need to document this shortcoming in the -ffpe-trap option doc.
Maybe one should put it additionally also in the documentation of the CPU_TIME
intrinsic subroutine.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (8 preceding siblings ...)
2007-09-21 11:45 ` burnus at gcc dot gnu dot org
@ 2007-09-21 11:59 ` fxcoudert at gcc dot gnu dot org
2007-09-26 22:27 ` fxcoudert at gcc dot gnu dot org
2007-09-26 22:28 ` fxcoudert at gcc dot gnu dot org
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From: fxcoudert at gcc dot gnu dot org @ 2007-09-21 11:59 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from fxcoudert at gcc dot gnu dot org 2007-09-21 11:59 -------
(In reply to comment #9)
> Maybe one should put it additionally also in the documentation of the CPU_TIME
> intrinsic subroutine.
Yep, but I suspect that CPU_TIME is not the only routine library routine that
can trigger this exception. I don't feel like going through all library
routines and check which can fail, but the I/O system certainly can trigger it
also, as Jerry observed, so I was thinking of adding a more general kind of
remark.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (9 preceding siblings ...)
2007-09-21 11:59 ` fxcoudert at gcc dot gnu dot org
@ 2007-09-26 22:27 ` fxcoudert at gcc dot gnu dot org
2007-09-26 22:28 ` fxcoudert at gcc dot gnu dot org
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From: fxcoudert at gcc dot gnu dot org @ 2007-09-26 22:27 UTC (permalink / raw)
To: gcc-bugs
------- Comment #11 from fxcoudert at gcc dot gnu dot org 2007-09-26 22:27 -------
Subject: Bug 30780
Author: fxcoudert
Date: Wed Sep 26 22:27:16 2007
New Revision: 128825
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=128825
Log:
PR fortran/30780
* invoke.texi: Add note to -ffpe-trap option. Fix typos.
Modified:
trunk/gcc/fortran/ChangeLog
trunk/gcc/fortran/invoke.texi
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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2007-02-12 21:08 [Bug fortran/30780] New: cpu_time produces a floating point exception when used with -O0 glv at maths dot otago dot ac dot nz
` (10 preceding siblings ...)
2007-09-26 22:27 ` fxcoudert at gcc dot gnu dot org
@ 2007-09-26 22:28 ` fxcoudert at gcc dot gnu dot org
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From: fxcoudert at gcc dot gnu dot org @ 2007-09-26 22:28 UTC (permalink / raw)
To: gcc-bugs
------- Comment #12 from fxcoudert at gcc dot gnu dot org 2007-09-26 22:28 -------
Documentation added.
--
fxcoudert at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.3.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30780
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