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* [Bug fortran/20026] New: Weird optimization affects cpu200/178.galgel testing
@ 2005-02-17 17:10 denis dot nagorny at intel dot com
2005-02-17 17:25 ` [Bug fortran/20026] " denis dot nagorny at intel dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: denis dot nagorny at intel dot com @ 2005-02-17 17:10 UTC (permalink / raw)
To: gcc-bugs
LAPACK tries to determine behavior of present double pre-
precision numbers. One of used methods is based on property
that (on IA32) 9.0071992547400992E+015 + 1 will be the same
9.0071992547400992E+015, but 9.0071992547400992E+015 + 2 will
be differ.
This sample demonstrates that any level of optimization in
gfortran version 4.0.0 20050215 breaks this functionality.
Due to this feature it's impossible now to use 178.galgel test from
cpu2000 testsuite.
Please compile following sample (I'll attach them also) with and without option
-O1. You'll obtain "Good" without optimization and "Bad" with -O1.
!!***************
REAL*8 A, B, C
REAL*8 foo
A = 9.0071992547400992E+015
B = 1
C = foo( A, B )
IF( C.EQ.A ) THEN
write(*,*) "Good"
ELSE
write(*,*) "Bad!!!"
write(*,*) "A=",A
write(*,*) "C=",C
END IF
END
!!******************************
FUNCTION foo( A, B )
REAL*8 foo
REAL*8 A, B
foo = A + B
RETURN
END
!!*********************
>gfortran -v
Using built-in specs.
Target: i586-suse-linux
Configured with: ../src/gcc/configure --enable-threads=posix
--prefix=/users/xxxxx/work/gcc40/real --disable-checking --enable-libgcj
--with-system-zlib --enable-shared --enable-__cxa_atexit i586-suse-linux
Thread model: posix
gcc version 4.0.0 20050215 (experimental
--
Summary: Weird optimization affects cpu200/178.galgel testing
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: critical
Priority: P2
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: denis dot nagorny at intel dot com
CC: gcc-bugs at gcc dot gnu dot org,grigory dot zagorodnev
at intel dot com
GCC build triplet: i586-suse-linux
GCC host triplet: i586-suse-linux
GCC target triplet: i586-suse-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20026
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug fortran/20026] Weird optimization affects cpu200/178.galgel testing
2005-02-17 17:10 [Bug fortran/20026] New: Weird optimization affects cpu200/178.galgel testing denis dot nagorny at intel dot com
@ 2005-02-17 17:25 ` denis dot nagorny at intel dot com
2005-02-17 17:41 ` [Bug target/20026] " pinskia at gcc dot gnu dot org
2005-02-17 17:44 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: denis dot nagorny at intel dot com @ 2005-02-17 17:25 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From denis dot nagorny at intel dot com 2005-02-17 13:28 -------
Created an attachment (id=8214)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8214&action=view)
sample for error reproducing
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20026
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/20026] Weird optimization affects cpu200/178.galgel testing
2005-02-17 17:10 [Bug fortran/20026] New: Weird optimization affects cpu200/178.galgel testing denis dot nagorny at intel dot com
2005-02-17 17:25 ` [Bug fortran/20026] " denis dot nagorny at intel dot com
@ 2005-02-17 17:41 ` pinskia at gcc dot gnu dot org
2005-02-17 17:44 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-02-17 17:41 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|critical |normal
Component|fortran |target
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20026
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/20026] Weird optimization affects cpu200/178.galgel testing
2005-02-17 17:10 [Bug fortran/20026] New: Weird optimization affects cpu200/178.galgel testing denis dot nagorny at intel dot com
2005-02-17 17:25 ` [Bug fortran/20026] " denis dot nagorny at intel dot com
2005-02-17 17:41 ` [Bug target/20026] " pinskia at gcc dot gnu dot org
@ 2005-02-17 17:44 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-02-17 17:44 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-02-17 13:37 -------
The problem is that on x86, we use the excessive precision, see PR 323.
This is a dup of bug 323.
*** This bug has been marked as a duplicate of 323 ***
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20026
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2005-02-17 13:41 UTC | newest]
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2005-02-17 17:10 [Bug fortran/20026] New: Weird optimization affects cpu200/178.galgel testing denis dot nagorny at intel dot com
2005-02-17 17:25 ` [Bug fortran/20026] " denis dot nagorny at intel dot com
2005-02-17 17:41 ` [Bug target/20026] " pinskia at gcc dot gnu dot org
2005-02-17 17:44 ` pinskia at gcc dot gnu dot org
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