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* [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures
@ 2011-12-05 23:37 dmalcolm at redhat dot com
2011-12-06 10:46 ` [Bug math/13472] " schwab@linux-m68k.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: dmalcolm at redhat dot com @ 2011-12-05 23:37 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=13472
Bug #: 13472
Summary: PPC64 hypot() is "inf" for very large values that are
non-infinite on other architectures
Product: glibc
Version: 2.14
Status: NEW
Severity: normal
Priority: P2
Component: math
AssignedTo: aj@suse.de
ReportedBy: dmalcolm@redhat.com
Classification: Unclassified
ppc64's glibc appears to have an optimized implementation of "hypot" (in libm):
sysdeps/powerpc/fpu/e_hypot.c
This seems to have different behavior near infinity when compared to other
architectures.
This leads to CPython's test suite failing on ppc64 with glibc-2.14.90-19.ppc64
(albeit with Fedora's build of glibc) within the "cmath" module (math on
complex numbers):
https://bugzilla.redhat.com/show_bug.cgi?id=750811
http://bugs.python.org/issue13534
CPython's "cmath" module internally uses hypot() in various cases of very large
numbers in order to avoid overflow. All of the failing test cases turned out
to involve (at the C layer) a call to hypot() with a pair of very large finite
values, where the result is very large but finite on other architectures, but
is "inf" on ppc64, leading to various unexpected values, and an
architecture-specific failure of this test.
"man hypot" says:
> The calculation is performed without undue overflow or underflow during
> the intermediate steps of the calculation.
Test case:
Python's math.hypot() is a thin wrapper around hypot(3); a Python "float" uses
a C "double" internally.
https://bugzilla.redhat.com/attachment.cgi?id=541097 is a Python script to
exercise hypot(3). It calls hypot() for all of the x,y pairs that fail within
the Python test case on ppc64.
On x86_64, with glibc-2.14-5.x86_64 (and python-2.7.1-7.fc15.x86_64), all
results are non-infinite, with exponent e+307 or e+308 (see:
https://bugzilla.redhat.com/attachment.cgi?id=541102
for the results on this box).
On ppc64, with glibc-2.14.90-19.ppc64 (and python-2.7.2-4.2.fc16.ppc64), all
results are "inf".
(hopefully the attachments on that other bugzilla instance are readable).
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug math/13472] PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com @ 2011-12-06 10:46 ` schwab@linux-m68k.org 2011-12-06 13:20 ` jakub at redhat dot com ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: schwab@linux-m68k.org @ 2011-12-06 10:46 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13472 Andreas Schwab <schwab@linux-m68k.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED --- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2011-12-06 10:45:50 UTC --- Fixed on master. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug math/13472] PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com 2011-12-06 10:46 ` [Bug math/13472] " schwab@linux-m68k.org @ 2011-12-06 13:20 ` jakub at redhat dot com 2011-12-06 13:27 ` schwab@linux-m68k.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: jakub at redhat dot com @ 2011-12-06 13:20 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13472 Jakub Jelinek <jakub at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |REOPENED CC| |jakub at redhat dot com Resolution|FIXED | --- Comment #2 from Jakub Jelinek <jakub at redhat dot com> 2011-12-06 13:19:52 UTC --- Can you explain where and how? I don't see any recent fixes for the buggy sysdeps/powerpc/fpu/e_hypot.c, all other architectures use a sane implementation, but this new powerpc implementation doesn't attempt to handle any corner cases except for the checks if larger one is > two500 or smaller one < twoM500. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug math/13472] PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com 2011-12-06 10:46 ` [Bug math/13472] " schwab@linux-m68k.org 2011-12-06 13:20 ` jakub at redhat dot com @ 2011-12-06 13:27 ` schwab@linux-m68k.org 2011-12-06 15:11 ` dmalcolm at redhat dot com 2014-06-27 11:32 ` fweimer at redhat dot com 4 siblings, 0 replies; 6+ messages in thread From: schwab@linux-m68k.org @ 2011-12-06 13:27 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13472 Andreas Schwab <schwab@linux-m68k.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|REOPENED |RESOLVED Resolution| |FIXED --- Comment #3 from Andreas Schwab <schwab@linux-m68k.org> 2011-12-06 13:26:56 UTC --- Forgot to push out. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug math/13472] PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com ` (2 preceding siblings ...) 2011-12-06 13:27 ` schwab@linux-m68k.org @ 2011-12-06 15:11 ` dmalcolm at redhat dot com 2014-06-27 11:32 ` fweimer at redhat dot com 4 siblings, 0 replies; 6+ messages in thread From: dmalcolm at redhat dot com @ 2011-12-06 15:11 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=13472 --- Comment #4 from Dave Malcolm <dmalcolm at redhat dot com> 2011-12-06 15:11:04 UTC --- Note to self: Fix appears to be: http://repo.or.cz/w/glibc.git/commit/850fb039cec802072f70ed9763927881bbbf639c -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug math/13472] PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com ` (3 preceding siblings ...) 2011-12-06 15:11 ` dmalcolm at redhat dot com @ 2014-06-27 11:32 ` fweimer at redhat dot com 4 siblings, 0 replies; 6+ messages in thread From: fweimer at redhat dot com @ 2014-06-27 11:32 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=13472 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Flags| |security- -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-06-27 11:32 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2011-12-05 23:37 [Bug math/13472] New: PPC64 hypot() is "inf" for very large values that are non-infinite on other architectures dmalcolm at redhat dot com 2011-12-06 10:46 ` [Bug math/13472] " schwab@linux-m68k.org 2011-12-06 13:20 ` jakub at redhat dot com 2011-12-06 13:27 ` schwab@linux-m68k.org 2011-12-06 15:11 ` dmalcolm at redhat dot com 2014-06-27 11:32 ` fweimer at redhat dot com
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