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* [Bug math/18030] New: [ldbl-128ibm] logbl wrong near powers of 2
@ 2015-02-25 22:14 jsm28 at gcc dot gnu.org
2015-02-26 12:58 ` [Bug math/18030] " cvs-commit at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: jsm28 at gcc dot gnu.org @ 2015-02-25 22:14 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=18030
Bug ID: 18030
Summary: [ldbl-128ibm] logbl wrong near powers of 2
Product: glibc
Version: 2.21
Status: NEW
Severity: normal
Priority: P2
Component: math
Assignee: unassigned at sourceware dot org
Reporter: jsm28 at gcc dot gnu.org
Similar to bug 18029 for ilogbl, the ldbl-128ibm implementation of logbl
produces incorrect results when the high part of the argument is a power of 2
and the low part a nonzero number with the opposite sign (and so the returned
exponent should be 1 less than that of the high part). For example, logbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1.
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* [Bug math/18030] [ldbl-128ibm] logbl wrong near powers of 2
2015-02-25 22:14 [Bug math/18030] New: [ldbl-128ibm] logbl wrong near powers of 2 jsm28 at gcc dot gnu.org
@ 2015-02-26 12:58 ` cvs-commit at gcc dot gnu.org
2015-02-26 15:16 ` cvs-commit at gcc dot gnu.org
2015-02-26 15:17 ` jsm28 at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2015-02-26 12:58 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=18030
--- Comment #1 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, master has been updated
via 524ae9ea2e3ae9f5bf5d655595fda827e9dc50a1 (commit)
from 23d43090e0b275e47e09e859823e965a1eb323dc (commit)
Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=524ae9ea2e3ae9f5bf5d655595fda827e9dc50a1
commit 524ae9ea2e3ae9f5bf5d655595fda827e9dc50a1
Author: Joseph Myers <joseph@codesourcery.com>
Date: Thu Feb 26 12:57:21 2015 +0000
Fix ldbl-128ibm ilogbl near powers of 2 (bug 18029).
The ldbl-128ibm implementation of ilogbl produces incorrect results
when the high part of the argument is a power of 2 and the low part a
nonzero number with the opposite sign (and so the returned exponent
should be 1 less than that of the high part). For example, ilogbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1. (This is
similar to (fixed) bug 16740 for frexpl, and bug 18030 for logbl.)
This patch adds checks for that case.
Tested for powerpc.
[BZ #18029]
* sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl):
Adjust exponent of power of 2 down when low part has opposite
sign.
* math/libm-test.inc (ilogb_test_data): Add more tests.
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 8 ++++++++
NEWS | 2 +-
math/libm-test.inc | 5 +++++
sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c | 23 +++++++++++++++++++----
4 files changed, 33 insertions(+), 5 deletions(-)
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* [Bug math/18030] [ldbl-128ibm] logbl wrong near powers of 2
2015-02-25 22:14 [Bug math/18030] New: [ldbl-128ibm] logbl wrong near powers of 2 jsm28 at gcc dot gnu.org
2015-02-26 12:58 ` [Bug math/18030] " cvs-commit at gcc dot gnu.org
@ 2015-02-26 15:16 ` cvs-commit at gcc dot gnu.org
2015-02-26 15:17 ` jsm28 at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2015-02-26 15:16 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=18030
--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, master has been updated
via 380bd0fd2418f8988217de950f8b8ff18af0cb2b (commit)
from 4a28f4d55a6cc33474c0792fe93b5942d81bf185 (commit)
Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
revisions in full, below.
- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=380bd0fd2418f8988217de950f8b8ff18af0cb2b
commit 380bd0fd2418f8988217de950f8b8ff18af0cb2b
Author: Joseph Myers <joseph@codesourcery.com>
Date: Thu Feb 26 15:13:22 2015 +0000
Fix ldbl-128ibm logbl near powers of 2 (bug 18030).
The ldbl-128ibm implementation of logbl produces incorrect results
when the high part of the argument is a power of 2 and the low part a
nonzero number with the opposite sign (and so the returned exponent
should be 1 less than that of the high part). For example, logbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1. (This is
similar to (fixed) bug 16740 for frexpl, and (fixed) bug 18029 for
ilogbl.) This patch adds checks for that case.
Tested for powerpc.
[BZ #18030]
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c (__logbl): Adjust exponent
of power of 2 down when low part has opposite sign.
* math/libm-test.inc (logb_test_data): Add more tests.
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 7 +++++++
NEWS | 2 +-
math/libm-test.inc | 5 +++++
sysdeps/ieee754/ldbl-128ibm/s_logbl.c | 17 ++++++++++++++---
4 files changed, 27 insertions(+), 4 deletions(-)
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* [Bug math/18030] [ldbl-128ibm] logbl wrong near powers of 2
2015-02-25 22:14 [Bug math/18030] New: [ldbl-128ibm] logbl wrong near powers of 2 jsm28 at gcc dot gnu.org
2015-02-26 12:58 ` [Bug math/18030] " cvs-commit at gcc dot gnu.org
2015-02-26 15:16 ` cvs-commit at gcc dot gnu.org
@ 2015-02-26 15:17 ` jsm28 at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: jsm28 at gcc dot gnu.org @ 2015-02-26 15:17 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=18030
Joseph Myers <jsm28 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
--- Comment #3 from Joseph Myers <jsm28 at gcc dot gnu.org> ---
Fixed for 2.22.
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2015-02-25 22:14 [Bug math/18030] New: [ldbl-128ibm] logbl wrong near powers of 2 jsm28 at gcc dot gnu.org
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2015-02-26 15:16 ` cvs-commit at gcc dot gnu.org
2015-02-26 15:17 ` jsm28 at gcc dot gnu.org
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