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| author | Joseph Myers <joseph@codesourcery.com> | 2013-04-27 14:56:34 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2013-04-27 14:57:41 +0000 |
| commit | 5b4217d71f592287bc77d80e08a20873bce86756 (patch) | |
| tree | 6c0cb83177b4bee4da605e7e3c6b91f798e2204b /math/s_catanl.c | |
| parent | d5ba74f76461d2eaca738413cd49bf28bebff2f1 (diff) | |
| download | glibc-5b4217d71f592287bc77d80e08a20873bce86756.tar.gz glibc-5b4217d71f592287bc77d80e08a20873bce86756.tar.xz glibc-5b4217d71f592287bc77d80e08a20873bce86756.zip | |
Fix catan, catanh spurious overflows (bug 15409).
Diffstat (limited to 'math/s_catanl.c')
| -rw-r--r-- | math/s_catanl.c | 55 |
1 files changed, 40 insertions, 15 deletions
diff --git a/math/s_catanl.c b/math/s_catanl.c index 2440e6d151..17ab62d340 100644 --- a/math/s_catanl.c +++ b/math/s_catanl.c @@ -22,6 +22,13 @@ #include <math_private.h> #include <float.h> +/* To avoid spurious overflows, use this definition to treat IBM long + double as approximating an IEEE-style format. */ +#if LDBL_MANT_DIG == 106 +# undef LDBL_EPSILON +# define LDBL_EPSILON 0x1p-106L +#endif + __complex__ long double __catanl (__complex__ long double x) { @@ -61,27 +68,45 @@ __catanl (__complex__ long double x) } else { - long double r2, num, den, f; + if (fabsl (__real__ x) >= 16.0L / LDBL_EPSILON + || fabsl (__imag__ x) >= 16.0L / LDBL_EPSILON) + { + __real__ res = __copysignl (M_PI_2l, __real__ x); + if (fabsl (__real__ x) <= 1.0L) + __imag__ res = 1.0L / __imag__ x; + else if (fabsl (__imag__ x) <= 1.0L) + __imag__ res = __imag__ x / __real__ x / __real__ x; + else + { + long double h = __ieee754_hypotl (__real__ x / 2.0L, + __imag__ x / 2.0L); + __imag__ res = __imag__ x / h / h / 4.0L; + } + } + else + { + long double r2, num, den, f; - r2 = __real__ x * __real__ x; + r2 = __real__ x * __real__ x; - den = 1 - r2 - __imag__ x * __imag__ x; + den = 1 - r2 - __imag__ x * __imag__ x; - __real__ res = 0.5L * __ieee754_atan2l (2.0L * __real__ x, den); + __real__ res = 0.5L * __ieee754_atan2l (2.0L * __real__ x, den); - num = __imag__ x + 1.0L; - num = r2 + num * num; + num = __imag__ x + 1.0L; + num = r2 + num * num; - den = __imag__ x - 1.0L; - den = r2 + den * den; + den = __imag__ x - 1.0L; + den = r2 + den * den; - f = num / den; - if (f < 0.5L) - __imag__ res = 0.25L * __ieee754_logl (f); - else - { - num = 4.0L * __imag__ x; - __imag__ res = 0.25L * __log1pl (num / den); + f = num / den; + if (f < 0.5L) + __imag__ res = 0.25L * __ieee754_logl (f); + else + { + num = 4.0L * __imag__ x; + __imag__ res = 0.25L * __log1pl (num / den); + } } if (fabsl (__real__ res) < LDBL_MIN) |