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| author | Joseph Myers <joseph@codesourcery.com> | 2012-09-29 18:31:54 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2012-09-29 18:31:54 +0000 |
| commit | 8ec5b01346114da38e806ca1867da688d3a360e2 (patch) | |
| tree | 8a55bd704c2a6ca8164202217e2048bb33a7dacb /sysdeps/ieee754/ldbl-96/s_fma.c | |
| parent | b1fa802e1ad4104060fe93b4b3b078ba46be0933 (diff) | |
| download | glibc-8ec5b01346114da38e806ca1867da688d3a360e2.tar.gz | |
Fix sign of exact zero return from fma (bug 14638).
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/s_fma.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-96/s_fma.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/sysdeps/ieee754/ldbl-96/s_fma.c b/sysdeps/ieee754/ldbl-96/s_fma.c index 78c0b0db18..001d8063d4 100644 --- a/sysdeps/ieee754/ldbl-96/s_fma.c +++ b/sysdeps/ieee754/ldbl-96/s_fma.c @@ -1,5 +1,5 @@ /* Compute x * y + z as ternary operation. - Copyright (C) 2010 Free Software Foundation, Inc. + Copyright (C) 2010-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Jakub Jelinek <jakub@redhat.com>, 2010. @@ -38,6 +38,10 @@ __fma (double x, double y, double z) return (x * y) + z; } + /* Ensure correct sign of exact 0 + 0. */ + if (__builtin_expect ((x == 0 || y == 0) && z == 0, 0)) + return x * y + z; + /* Multiplication m1 + m2 = x * y using Dekker's algorithm. */ #define C ((1ULL << (LDBL_MANT_DIG + 1) / 2) + 1) long double x1 = (long double) x * C; |