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authorJoseph Myers <joseph@codesourcery.com>2012-03-19 20:13:10 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-03-19 20:14:26 +0000
commit1897ad44326bb7761dcda46132ae303f7288aba9 (patch)
treefd8357b0066902deb5b6b9476b8c456f68ffc56e /math/s_clogf.c
parent7726d6a95d5a2c08c8d43186002f040b9b889c27 (diff)
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Fix clog overflow/underflow (bug 13629).
Diffstat (limited to 'math/s_clogf.c')
-rw-r--r--math/s_clogf.c28
1 files changed, 23 insertions, 5 deletions
diff --git a/math/s_clogf.c b/math/s_clogf.c
index eb8433a280..0b27506fb4 100644
--- a/math/s_clogf.c
+++ b/math/s_clogf.c
@@ -1,5 +1,5 @@
/* Compute complex natural 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.
@@ -19,9 +19,8 @@
#include <complex.h>
#include <math.h>
-
#include <math_private.h>
-
+#include <float.h>
__complex__ float
__clogf (__complex__ float x)
@@ -41,8 +40,27 @@ __clogf (__complex__ float x)
else if (__builtin_expect (rcls != FP_NAN && icls != FP_NAN, 1))
{
/* Neither real nor imaginary part is NaN. */
- __real__ result = __ieee754_logf (__ieee754_hypotf (__real__ x,
- __imag__ x));
+ float d;
+ int scale = 0;
+
+ if (fabsf (__real__ x) > FLT_MAX / 2.0f
+ || fabsf (__imag__ x) > FLT_MAX / 2.0f)
+ {
+ scale = -1;
+ __real__ x = __scalbnf (__real__ x, scale);
+ __imag__ x = __scalbnf (__imag__ x, scale);
+ }
+ else if (fabsf (__real__ x) < FLT_MIN
+ && fabsf (__imag__ x) < FLT_MIN)
+ {
+ scale = FLT_MANT_DIG;
+ __real__ x = __scalbnf (__real__ x, scale);
+ __imag__ x = __scalbnf (__imag__ x, scale);
+ }
+
+ d = __ieee754_hypotf (__real__ x, __imag__ x);
+
+ __real__ result = __ieee754_logf (d) - scale * (float) M_LN2;
__imag__ result = __ieee754_atan2f (__imag__ x, __real__ x);
}
else