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Fix cexp overflow (bug 13892).

This commit is contained in:
Joseph Myers
2012-03-22 19:38:09 +00:00
parent 81b035fe63
commit 7c69cd143b
8 changed files with 181 additions and 27 deletions

View File

@ -1,5 +1,5 @@
/* Return value of complex exponential function for float complex value.
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.
@ -21,7 +21,7 @@
#include <fenv.h>
#include <math.h>
#include <math_private.h>
#include <float.h>
__complex__ float
__cexpf (__complex__ float x)
@ -36,20 +36,35 @@ __cexpf (__complex__ float x)
if (__builtin_expect (icls >= FP_ZERO, 1))
{
/* Imaginary part is finite. */
float exp_val = __ieee754_expf (__real__ x);
const int t = (int) ((FLT_MAX_EXP - 1) * M_LN2);
float sinix, cosix;
__sincosf (__imag__ x, &sinix, &cosix);
if (isfinite (exp_val))
if (__real__ x > t)
{
__real__ retval = exp_val * cosix;
__imag__ retval = exp_val * sinix;
float exp_t = __ieee754_expf (t);
__real__ x -= t;
sinix *= exp_t;
cosix *= exp_t;
if (__real__ x > t)
{
__real__ x -= t;
sinix *= exp_t;
cosix *= exp_t;
}
}
if (__real__ x > t)
{
/* Overflow (original real part of x > 3t). */
__real__ retval = FLT_MAX * cosix;
__imag__ retval = FLT_MAX * sinix;
}
else
{
__real__ retval = __copysignf (exp_val, cosix);
__imag__ retval = __copysignf (exp_val, sinix);
float exp_val = __ieee754_expf (__real__ x);
__real__ retval = exp_val * cosix;
__imag__ retval = exp_val * sinix;
}
}
else