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Fix clog overflow/underflow (bug 13629).

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This commit is contained in:
Joseph Myers
2012-03-19 20:13:10 +00:00
parent 7726d6a95d
commit 1897ad4432
10 changed files with 322 additions and 22 deletions
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28
math/s_clog10.c
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@ -1,5 +1,5 @@
/* Compute complex base 10 logarithm.
Copyright (C) 1997, 2011 Free Software Foundation, Inc.
Copyright (C) 1997-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
@ -20,7 +20,10 @@
#include <complex.h>
#include <math.h>
#include <math_private.h>
#include <float.h>
/* log_10 (2). */
#define M_LOG10_2 0.3010299956639811952137388947244930267682
__complex__ double
__clog10 (__complex__ double x)
@ -40,8 +43,27 @@ __clog10 (__complex__ double x)
else if (__builtin_expect (rcls != FP_NAN && icls != FP_NAN, 1))
{
/* Neither real nor imaginary part is NaN. */
__real__ result = __ieee754_log10 (__ieee754_hypot (__real__ x,
__imag__ x));
double d;
int scale = 0;
if (fabs (__real__ x) > DBL_MAX / 2.0
|| fabs (__imag__ x) > DBL_MAX / 2.0)
{
scale = -1;
__real__ x = __scalbn (__real__ x, scale);
__imag__ x = __scalbn (__imag__ x, scale);
}
else if (fabs (__real__ x) < DBL_MIN
&& fabs (__imag__ x) < DBL_MIN)
{
scale = DBL_MANT_DIG;
__real__ x = __scalbn (__real__ x, scale);
__imag__ x = __scalbn (__imag__ x, scale);
}
d = __ieee754_hypot (__real__ x, __imag__ x);
__real__ result = __ieee754_log10 (d) - scale * M_LOG10_2;
__imag__ result = M_LOG10E * __ieee754_atan2 (__imag__ x, __real__ x);
}
else