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authorJoseph Myers <joseph@codesourcery.com>2014-03-28 20:53:32 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-03-28 20:53:32 +0000
commit289e0779571a36a8f30ae0408b4902bb7f2ab92e (patch)
treeb958fb51b0657f12d0571e4d82c2069a2929570f /math/s_clog10f.c
parent277ae3f186eb9158219aacf20199cdd02ad133e7 (diff)
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Fix clog10 (-0 +/- 0i) (bug 16362).
This patch fixes the imaginary part of clog10 (-0 +/- 0i), which should be +/-pi / log(10) by analogy with clog (the functions were wrongly returning a result with imaginary part +/-pi, same as for clog, and the tests matched the incorrect result, though both functions and tests were correct for the similar case of clog10 (-inf +/- 0i)). Tested x86_64 and x86. [BZ #16362] * math/s_clog10.c (M_PI_LOG10E): New macro. (__clog10): Use M_PI_LOG10E instead of M_PI when real and imaginary parts are 0. * math/s_clog10f.c (M_PI_LOG10Ef): New macro. (__clog10f): Use M_PI_LOG10Ef instead of M_PI when real and imaginary parts are 0. * math/s_clog10l.c (M_PI_LOG10El): New macro. (__clog10l): Use M_PI_LOG10El instead of M_PIl when real and imaginary parts are 0. * math/libm-test.inc (clog10_test_data): Update expected results for when real and imaginary parts are 0.
Diffstat (limited to 'math/s_clog10f.c')
-rw-r--r--math/s_clog10f.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/math/s_clog10f.c b/math/s_clog10f.c
index a9120e03f8..ca2cdf4f80 100644
--- a/math/s_clog10f.c
+++ b/math/s_clog10f.c
@@ -25,6 +25,9 @@
/* log_10 (2). */
#define M_LOG10_2f 0.3010299956639811952137388947244930267682f
+/* pi * log10 (e). */
+#define M_PI_LOG10Ef 1.364376353841841347485783625431355770210f
+
__complex__ float
__clog10f (__complex__ float x)
{
@@ -35,7 +38,7 @@ __clog10f (__complex__ float x)
if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
{
/* Real and imaginary part are 0.0. */
- __imag__ result = signbit (__real__ x) ? M_PI : 0.0;
+ __imag__ result = signbit (__real__ x) ? M_PI_LOG10Ef : 0.0;
__imag__ result = __copysignf (__imag__ result, __imag__ x);
/* Yes, the following line raises an exception. */
__real__ result = -1.0 / fabsf (__real__ x);