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author | Joseph Myers <joseph@codesourcery.com> | 2015-12-09 21:20:18 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2015-12-09 21:20:18 +0000 |
commit | ca2fcac629b9b7781ccd52685b28741d89ff128f (patch) | |
tree | 8c2b6491a4672a338e965e8ca1fa0f8724d189a6 /ChangeLog | |
parent | e5a5315e2d290fe34e0fb80996c713b8b802dcc9 (diff) | |
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Fix ldbl-128ibm tanhl inaccuracy for small arguments (bug 19349).
The ldbl-128ibm implementation of tanhl is inaccurate for small
arguments, because it returns x*(1+x) (maybe in an attempt to raise
"inexact") when x itself would be the accurate return value but
multiplying by 1+x introduces large errors. This patch fixes it to
return x in that case (when the mathematical result is x plus a
negligible remainder on the order of x^3) to avoid those errors.
Tested for powerpc.
[BZ #19349]
* sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Return argument
when small.
Diffstat (limited to 'ChangeLog')
-rw-r--r-- | ChangeLog | 4 |
1 files changed, 4 insertions, 0 deletions
@@ -1,5 +1,9 @@ 2015-12-09 Joseph Myers <joseph@codesourcery.com> + [BZ #19349] + * sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Return argument + when small. + * sysdeps/unix/sysv/linux/i386/kernel-features.h [__LINUX_KERNEL_VERSION >= 0x040300] (__ASSUME_SOCKET_SYSCALL): New macro. |