Commit Graph

13 Commits

Author SHA1 Message Date
Joseph Myers 718d34a309 Fix csqrt spurious underflows (bug 18371).
The csqrt implementations in glibc can cause spurious underflows in
some cases as a side-effect of the scaling for large arguments (when
underflow is correct for the square root of the argument that was
scaled down to avoid overflow, but not for the original argument).
This patch arranges to avoid the underflowing intermediate computation
(eliminating a multiplication in 0.5 in the problem cases where a
subsequent scaling by 2 would follow).

Tested for x86_64 and x86 and ulps updated accordingly (only needed
for x86).

	[BZ #18371]
	* math/s_csqrt.c (__csqrt): Avoid multiplication by 0.5 where
	intermediate but not final result might underflow.
	* math/s_csqrtf.c (__csqrtf): Likewise.
	* math/s_csqrtl.c (__csqrtl): Likewise.
	* math/auto-libm-test-in: Add more tests of csqrt.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
2015-06-23 16:01:54 +00:00
Joseph Myers b168057aaa Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
Ondřej Bílka a1ffb40e32 Use glibc_likely instead __builtin_expect. 2014-02-10 15:07:12 +01:00
Allan McRae d4697bc93d Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
Joseph Myers 568035b787 Update copyright notices with scripts/update-copyrights. 2013-01-02 19:05:09 +00:00
Joseph Myers cdfe2c5eb3 Fix csqrt underflow (bugs 14157, 14331). 2012-07-05 11:02:13 +00:00
Joseph Myers e456826d7a Fix csqrt overflow/underflow (bug 13841). 2012-03-14 11:53:32 +00:00
Paul Eggert 59ba27a63a Replace FSF snail mail address with URLs. 2012-02-09 23:18:22 +00:00
Ulrich Drepper 77425c63e7 Add branch predictions to complex math code 2011-10-22 13:17:30 -04:00
Ulrich Drepper 9277c06437 Use private math_private.h in files in math/ 2011-10-08 05:16:04 -04:00
Ulrich Drepper 9d13fb2413 Moved to csu/errno-loc.c. 2005-12-14 15:06:39 +00:00
Ulrich Drepper a334319f65 (CFLAGS-tst-align.c): Add -mpreferred-stack-boundary=4. 2004-12-22 20:10:10 +00:00
Jakub Jelinek 0ecb606cb6 2.5-18.1 2007-07-12 18:26:36 +00:00