From 01dbacd22a8d5e0053f8d0cf13a80286b6cfe79b Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 14 May 2014 12:37:24 +0000 Subject: Fix cacos (+Inf + finite*i) in round-downward mode (bug 16928). According to C99/C11 Annex G, cacos applied to a value with real part +Inf and finite imaginary part should produce a result with real part +0. glibc wrongly produces a result with real part -0 in FE_DOWNWARD mode. This patch fixes this by checking for zero results in the relevant case of non-finite arguments (where there should never be a result with -0 real part), and converts the tests of cacos to ALL_RM_TEST. Tested x86_64 and x86 and ulps updated accordingly. [BZ #16928] * math/s_cacos.c (__cacos): Ensure zero real part of result from non-finite arguments is +0. * math/s_cacosf.c (__cacosf): Likewise. * math/s_cacosl.c (__cacosl): Likewise. * math/libm-test.inc (cacos_test): Use ALL_RM_TEST. * sysdeps/i386/fpu/libm-test-ulps: Update. * sysdeps/x86_64/fpu/libm-test-ulps: Likewise. --- math/s_cacosf.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'math/s_cacosf.c') diff --git a/math/s_cacosf.c b/math/s_cacosf.c index 9eaeeec53d..1c9d8b9186 100644 --- a/math/s_cacosf.c +++ b/math/s_cacosf.c @@ -34,6 +34,8 @@ __cacosf (__complex__ float x) y = __casinf (x); __real__ res = (float) M_PI_2 - __real__ y; + if (__real__ res == 0.0f) + __real__ res = 0.0f; __imag__ res = -__imag__ y; } else -- cgit 1.4.1