From 8f8f8ef7aba40ef883291e4c4d95a419c3327d70 Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Tue, 3 Oct 2017 17:13:18 +0100 Subject: [PATCH] [BZ #22243] fix log2(0) and log(10) in downward rounding On 64bit targets if the SVID compat wrapper is suppressed (e.g. static linking) then log2(0) and log10(0) returned inf instead of -inf. [BZ #22243] * sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c (__ieee754_log10): Use fabs. * sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c (__ieee754_log2): Likewise. --- ChangeLog | 6 ++++++ sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c | 2 +- sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c | 2 +- 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index a8d731c75d..6161509499 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2017-10-04 Szabolcs Nagy + + [BZ #22243] + * sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c (__ieee754_log10): Use fabs. + * sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c (__ieee754_log2): Likewise. + 2017-10-03 H.J. Lu * sysdeps/i386/start.S: Replace "leal main@GOT(%ebx), %eax" with diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c b/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c index 4f5a81669e..cd5567182f 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/e_log10.c @@ -65,7 +65,7 @@ __ieee754_log10 (double x) if (hx < INT64_C(0x0010000000000000)) { /* x < 2**-1022 */ if (__glibc_unlikely ((hx & UINT64_C(0x7fffffffffffffff)) == 0)) - return -two54 / (x - x); /* log(+-0)=-inf */ + return -two54 / fabs (x); /* log(+-0)=-inf */ if (__glibc_unlikely (hx < 0)) return (x - x) / (x - x); /* log(-#) = NaN */ k -= 54; diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c b/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c index 5ccb78cf03..f08d5b337d 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c @@ -81,7 +81,7 @@ __ieee754_log2 (double x) if (hx < INT64_C(0x0010000000000000)) { /* x < 2**-1022 */ if (__glibc_unlikely ((hx & UINT64_C(0x7fffffffffffffff)) == 0)) - return -two54 / (x - x); /* log(+-0)=-inf */ + return -two54 / fabs (x); /* log(+-0)=-inf */ if (__glibc_unlikely (hx < 0)) return (x - x) / (x - x); /* log(-#) = NaN */ k -= 54; -- 2.43.5