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author | Joseph Myers <joseph@codesourcery.com> | 2014-03-21 18:13:58 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2014-03-21 18:13:58 +0000 |
commit | f7be737659813220e1f29c8850c386a9654d549a (patch) | |
tree | c047f314e8eca5df155322e4fe9471593fb07b67 /NEWS | |
parent | a387428ca7330513d5f2a0924c45e6382d477052 (diff) | |
download | glibc-f7be737659813220e1f29c8850c386a9654d549a.zip glibc-f7be737659813220e1f29c8850c386a9654d549a.tar.gz glibc-f7be737659813220e1f29c8850c386a9654d549a.tar.bz2 |
Fix log (1) in round-downward mode (bug 16731).
According to ISO C Annex F, log (1) should be +0 in all rounding
modes, but some implementations in glibc wrongly return -0 in
round-downward mode (mapping to log1p (x - 1) is problematic because 1
- 1 is -0 in round-downward mode, and log1p (-0) is -0). This patch
fixes this. (It helps with some implementations of other functions
such as acosh, log2 and log10 that call out to log, but not enough to
enable all-rounding-modes testing for those functions without further
fixes to other implementations of them.)
Tested x86_64 and x86 and ulps updated accordingly, and did spot tests
for mips64 for the ldbl-128 fix, and i586 for the sysdeps/i386/fpu
implementations shadowed by those in sysdeps/i386/i686/fpu.
[BZ #16731]
* sysdeps/i386/fpu/e_log.S (__ieee754_log): Take absolute value
when x - 1 is zero.
* sysdeps/i386/fpu/e_logf.S (__ieee754_logf): Likewise.
* sysdeps/i386/fpu/e_logl.S (__ieee754_logl): Likewise.
* sysdeps/i386/i686/fpu/e_logl.S (__ieee754_logl): Likewise.
* sysdeps/ieee754/dbl-64/e_log.c (__ieee754_log): Return +0 when
argument is 1.
* sysdeps/ieee754/ldbl-128/e_logl.c (__ieee754_logl): Likewise.
* sysdeps/x86_64/fpu/e_logl.S: Take absolute value when x - 1 is
zero.
* math/libm-test.inc (log_test): Use ALL_RM_TEST.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Diffstat (limited to 'NEWS')
-rw-r--r-- | NEWS | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -11,7 +11,7 @@ Version 2.20 15347, 15804, 15894, 16447, 16532, 16545, 16574, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16639, 16642, 16649, 16670, 16674, 16677, - 16680, 16683, 16689, 16695, 16701, 16706, 16707. + 16680, 16683, 16689, 16695, 16701, 16706, 16707, 16731. * Running the testsuite no longer terminates as soon as a test fails. Instead, a file tests.sum (xtests.sum from "make xcheck") is generated, |