From 4ba7a00fe3779e6ffafad6d47305b3491cdac33e Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 18 Jun 2014 12:32:01 +0000 Subject: Fix __ieee754_logl (-LDBL_MAX) in FE_DOWNWARD mode (bug 17022). This patch fixes __ieee754_logl (-LDBL_MAX) on x86_64 and x86 not to subtract 1 from its argument and so cause spurious overflow in FE_DOWNWARD mode. (For any argument strictly less than -1, it doesn't matter whether or not 1 is subtracted before computing log1p, as long as the result doesn't overflow to -Inf.) Tested x86_64 and x86. (This particular case lacks test coverage, since the testsuite doesn't cover -lieee, but it will be covered by tests after the following patch to test pow in all rounding modes, which was the context in which this bug was found.) [BZ #17022] * sysdeps/i386/fpu/e_logl.S (__ieee754_logl): Do not subtract 1 from arguments -2 or below. * sysdeps/i386/i686/fpu/e_logl.S (__ieee754_logl): Likewise. * sysdeps/x86_64/fpu/e_logl.S (__ieee754_logl): Likewise. --- ChangeLog | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'ChangeLog') diff --git a/ChangeLog b/ChangeLog index 997cec628a..3204c4e046 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2014-06-18 Joseph Myers + + [BZ #17022] + * sysdeps/i386/fpu/e_logl.S (__ieee754_logl): Do not subtract 1 + from arguments -2 or below. + * sysdeps/i386/i686/fpu/e_logl.S (__ieee754_logl): Likewise. + * sysdeps/x86_64/fpu/e_logl.S (__ieee754_logl): Likewise. + 2014-06-18 Andreas Schwab [BZ #17062] -- cgit 1.4.1