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authorJoseph Myers <joseph@codesourcery.com>2014-04-02 17:41:02 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-04-02 17:41:02 +0000
commita84e78c8b3c4de94b488fdc5321f71feeb99358f (patch)
treeb4e8a63fd2eb10f4598a5af855e6462a9b06767e /math/s_catan.c
parent6f05bafebac30a389807979f8efbb709f84b486f (diff)
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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.
Diffstat (limited to 'math/s_catan.c')
-rw-r--r--math/s_catan.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/math/s_catan.c b/math/s_catan.c
index d6552d8b7c..0cfa92434a 100644
--- a/math/s_catan.c
+++ b/math/s_catan.c
@@ -89,7 +89,11 @@ __catan (__complex__ double x)
}
if (absy < DBL_EPSILON / 2.0)
- den = (1.0 - absx) * (1.0 + absx);
+ {
+ den = (1.0 - absx) * (1.0 + absx);
+ if (den == -0.0)
+ den = 0.0;
+ }
else if (absx >= 1.0)
den = (1.0 - absx) * (1.0 + absx) - absy * absy;
else if (absx >= 0.75 || absy >= 0.5)