glibc/sysdeps/ieee754
Joseph Myers a84e78c8b3 Fix catan, catanh, __ieee754_logf in round-downward mode (bug 16799, bug 16800).
This patch fixes incorrect results from catan and catanh of certain
special inputs in round-downward mode (bug 16799), and incorrect
results of __ieee754_logf (+/-0) in round-downward mode (bug 16800)
that show up through catan/catanh when tested in all rounding modes,
but not directly in the testing for logf because the bug gets hidden
by the wrappers.

Both bugs involve a zero that should be +0 being -0 instead: one
computed as (1-x)*(1+x) in the catan/catanh case, and one as (x-x) in
the logf case.  The fixes ensure positive zero is used.  Testing of
catan and catanh in all rounding modes is duly enabled.

I expect there are various other bugs in special cases in __ieee754_*
functions that are normally hidden by the wrappers but would show up
for testing with -lieee (or in future with -fno-math-errno if we
replace -lieee and _LIB_VERSION with compile-time redirection to new
*_noerrno symbol names).

Tested x86_64 and x86 and ulps updated accordingly.

	[BZ #16799]
	[BZ #16800]
	* math/s_catan.c (__catan): Avoid passing -0 denominator to atan2
	with 0 numerator.
	* math/s_catanf.c (__catanf): Likewise.
	* math/s_catanh.c (__catanh): Likewise.
	* math/s_catanhf.c (__catanhf): Likewise.
	* math/s_catanhl.c (__catanhl): Likewise.
	* math/s_catanl.c (__catanl): Likewise.
	* sysdeps/ieee754/flt-32/e_logf.c (__ieee754_logf): Always divide
	by positive zero when computing -Inf result.
	* math/libm-test.inc (catan_test): Use ALL_RM_TEST.
	(catanh_test): Likewise.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2014-04-02 17:41:02 +00:00
..
bits Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
dbl-64 Fix implicit __isinf declarations in exp. 2014-03-24 22:00:32 +00:00
flt-32 Fix catan, catanh, __ieee754_logf in round-downward mode (bug 16799, bug 16800). 2014-04-02 17:41:02 +00:00
ldbl-64-128 Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
ldbl-96 Use glibc_likely instead __builtin_expect. 2014-02-10 15:07:12 +01:00
ldbl-128 Fix log (1) in round-downward mode (bug 16731). 2014-03-21 18:13:58 +00:00
ldbl-128ibm Correct IBM long double nextafterl. 2014-04-02 13:46:19 +10:30
ldbl-opt Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
Makefile
ieee754.h Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
k_standard.c Fix Bessel function error handling (bug 6807, bug 15901). 2013-12-04 14:39:37 +00:00
s_lib_version.c Remove trailing whitespace. 2013-06-05 20:44:03 +00:00
s_matherr.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
s_signgam.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
support.c Fix leading whitespaces. 2013-06-06 20:36:07 +02:00