diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128/s_expm1l.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128/s_expm1l.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/sysdeps/ieee754/ldbl-128/s_expm1l.c b/sysdeps/ieee754/ldbl-128/s_expm1l.c index f708af504c..573d00be57 100644 --- a/sysdeps/ieee754/ldbl-128/s_expm1l.c +++ b/sysdeps/ieee754/ldbl-128/s_expm1l.c @@ -137,9 +137,18 @@ __expm1l (long double x) if (x < minarg) return (4.0/big - 1.0L); - /* Avoid internal underflow when result does not underflow. */ - if (fabsl (x) < 0x1p-113L && fabsl (x) >= LDBL_MIN) - return x; + /* Avoid internal underflow when result does not underflow, while + ensuring underflow (without returning a zero of the wrong sign) + when the result does underflow. */ + if (fabsl (x) < 0x1p-113L) + { + if (fabsl (x) < LDBL_MIN) + { + long double force_underflow = x * x; + math_force_eval (force_underflow); + } + return x; + } /* Express x = ln 2 (k + remainder), remainder not exceeding 1/2. */ xx = C1 + C2; /* ln 2. */ |