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authorJoseph Myers <joseph@codesourcery.com>2013-04-27 14:56:34 +0000
committerJoseph Myers <joseph@codesourcery.com>2013-04-27 14:57:41 +0000
commit5b4217d71f592287bc77d80e08a20873bce86756 (patch)
tree6c0cb83177b4bee4da605e7e3c6b91f798e2204b /math/s_catanh.c
parentd5ba74f76461d2eaca738413cd49bf28bebff2f1 (diff)
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Fix catan, catanh spurious overflows (bug 15409).
Diffstat (limited to 'math/s_catanh.c')
-rw-r--r--math/s_catanh.c47
1 files changed, 32 insertions, 15 deletions
diff --git a/math/s_catanh.c b/math/s_catanh.c
index 5d18cd639f..55c56283b3 100644
--- a/math/s_catanh.c
+++ b/math/s_catanh.c
@@ -56,26 +56,43 @@ __catanh (__complex__ double x)
}
else
{
- double i2 = __imag__ x * __imag__ x;
+ if (fabs (__real__ x) >= 16.0 / DBL_EPSILON
+ || fabs (__imag__ x) >= 16.0 / DBL_EPSILON)
+ {
+ __imag__ res = __copysign (M_PI_2, __imag__ x);
+ if (fabs (__imag__ x) <= 1.0)
+ __real__ res = 1.0 / __real__ x;
+ else if (fabs (__real__ x) <= 1.0)
+ __real__ res = __real__ x / __imag__ x / __imag__ x;
+ else
+ {
+ double h = __ieee754_hypot (__real__ x / 2.0, __imag__ x / 2.0);
+ __real__ res = __real__ x / h / h / 4.0;
+ }
+ }
+ else
+ {
+ double i2 = __imag__ x * __imag__ x;
- double num = 1.0 + __real__ x;
- num = i2 + num * num;
+ double num = 1.0 + __real__ x;
+ num = i2 + num * num;
- double den = 1.0 - __real__ x;
- den = i2 + den * den;
+ double den = 1.0 - __real__ x;
+ den = i2 + den * den;
- double f = num / den;
- if (f < 0.5)
- __real__ res = 0.25 * __ieee754_log (f);
- else
- {
- num = 4.0 * __real__ x;
- __real__ res = 0.25 * __log1p (num / den);
- }
+ double f = num / den;
+ if (f < 0.5)
+ __real__ res = 0.25 * __ieee754_log (f);
+ else
+ {
+ num = 4.0 * __real__ x;
+ __real__ res = 0.25 * __log1p (num / den);
+ }
- den = 1 - __real__ x * __real__ x - i2;
+ den = 1 - __real__ x * __real__ x - i2;
- __imag__ res = 0.5 * __ieee754_atan2 (2.0 * __imag__ x, den);
+ __imag__ res = 0.5 * __ieee754_atan2 (2.0 * __imag__ x, den);
+ }
if (fabs (__real__ res) < DBL_MIN)
{