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authorAdhemerval Zanella <azanella@linux.vnet.ibm.com>2012-04-26 11:18:11 -0500
committerRyan S. Arnold <rsa@linux.vnet.ibm.com>2012-04-26 11:18:11 -0500
commit0ac229c819afd15ba323838ba72d0a409f16acc4 (patch)
tree0d048606e0862cf36d0e3798fe623fca0d41c859 /sysdeps
parent33f244f40b38fda964ccbfd4fa928a3d3d738f53 (diff)
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Fix ctan, ctanh overflow for ldbl-128ibm (bug 11521).
Diffstat (limited to 'sysdeps')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/e_sinhl.c3
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c43
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_ctanl.c48
-rw-r--r--sysdeps/powerpc/fpu/libm-test-ulps77
4 files changed, 138 insertions, 33 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c b/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
index 4bae85a..4e8481c 100644
--- a/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
@@ -54,7 +54,8 @@ __ieee754_sinhl(long double x)
if(shuge+x>one) return x;/* sinhl(tiny) = tiny with inexact */
t = __expm1l(fabsl(x));
if(ix<0x3ff0000000000000LL) return h*(2.0*t-t*t/(t+one));
- return h*(t+t/(t+one));
+ w = t/(t+one);
+ return h*(t+w);
}
/* |x| in [40, log(maxdouble)] return 0.5*exp(|x|) */
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c b/sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c
index e412639..2ab80a2 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c
@@ -1,5 +1,5 @@
/* Complex hyperbole tangent for long double. IBM extended format version.
- Copyright (C) 1997,2005,2006 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.
@@ -19,6 +19,7 @@
#include <complex.h>
#include <fenv.h>
+#include <float.h>
#include <math.h>
#include <math_ldbl_opt.h>
@@ -54,24 +55,44 @@ __ctanhl (__complex__ long double x)
}
else
{
- long double sin2ix, cos2ix;
+ long double sinix, cosix;
long double den;
+ const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2);
- __sincosl (2.0 * __imag__ x, &sin2ix, &cos2ix);
+ /* tanh(x+iy) = (sinh(2x) + i*sin(2y))/(cosh(2x) + cos(2y))
+ = (sinh(x)*cosh(x) + i*sin(y)*cos(y))/(sinh(x)^2 + cos(y)^2). */
- den = (__ieee754_coshl (2.0 * __real__ x) + cos2ix);
+ __sincosl (__imag__ x, &sinix, &cosix);
- if (den == 0.0L)
+ if (fabsl (__real__ x) > t)
{
- __complex__ long double ez = __cexpl (x);
- __complex__ long double emz = __cexpl (-x);
-
- res = (ez - emz) / (ez + emz);
+ /* Avoid intermediate overflow when the imaginary part of
+ the result may be subnormal. Ignoring negligible terms,
+ the real part is +/- 1, the imaginary part is
+ sin(y)*cos(y)/sinh(x)^2 = 4*sin(y)*cos(y)/exp(2x). */
+ long double exp_2t = __ieee754_expl (2 * t);
+ __real__ res = __copysignl (1.0, __real__ x);
+ __imag__ res = 4 * sinix * cosix;
+ __real__ x = fabsl (__real__ x);
+ __real__ x -= t;
+ __imag__ res /= exp_2t;
+ if (__real__ x > t)
+ {
+ /* Underflow (original real part of x has absolute value
+ > 2t). */
+ __imag__ res /= exp_2t;
+ }
+ else
+ __imag__ res /= __ieee754_expl (2 * __real__ x);
}
else
{
- __real__ res = __ieee754_sinhl (2.0 * __real__ x) / den;
- __imag__ res = sin2ix / den;
+ long double sinhrx = __ieee754_sinhl (__real__ x);
+ long double coshrx = __ieee754_coshl (__real__ x);
+
+ den = sinhrx * sinhrx + cosix * cosix;
+ __real__ res = sinhrx * coshrx / den;
+ __imag__ res = sinix * cosix / den;
}
/* __gcc_qmul does not respect -0.0 so we need the following fixup. */
if ((__real__ res == 0.0) && (__real__ x == 0.0))
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_ctanl.c b/sysdeps/ieee754/ldbl-128ibm/s_ctanl.c
index 0b1bc4f..9d89bbe 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_ctanl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_ctanl.c
@@ -1,5 +1,5 @@
/* Complex tangent function for long double. IBM extended format version.
- Copyright (C) 1997,2005,2006 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.
@@ -21,6 +21,7 @@
#include <fenv.h>
#include <math.h>
#include <math_ldbl_opt.h>
+#include <float.h>
#include <math_private.h>
@@ -46,34 +47,53 @@ __ctanl (__complex__ long double x)
__real__ res = __nanl ("");
__imag__ res = __nanl ("");
-#ifdef FE_INVALID
- if (__isinfl (__real__ x))
+ if (__isinf_nsl (__real__ x))
feraiseexcept (FE_INVALID);
-#endif
}
}
else
{
- long double sin2rx, cos2rx;
+ long double sinrx, cosrx;
long double den;
+ const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2);
- __sincosl (2.0 * __real__ x, &sin2rx, &cos2rx);
+ /* tan(x+iy) = (sin(2x) + i*sinh(2y))/(cos(2x) + cosh(2y))
+ = (sin(x)*cos(x) + i*sinh(y)*cosh(y)/(cos(x)^2 + sinh(y)^2). */
- den = cos2rx + __ieee754_coshl (2.0 * __imag__ x);
+ __sincosl (__real__ x, &sinrx, &cosrx);
-
- if (den == 0.0)
+ if (fabsl (__imag__ x) > t)
{
- __complex__ long double ez = __cexpl (1.0i * x);
- __complex__ long double emz = __cexpl (-1.0i * x);
+ /* Avoid intermediate overflow when the real part of the
+ result may be subnormal. Ignoring negligible terms, the
+ imaginary part is +/- 1, the real part is
+ sin(x)*cos(x)/sinh(y)^2 = 4*sin(x)*cos(x)/exp(2y). */
+ long double exp_2t = __ieee754_expl (2 * t);
- res = (ez - emz) / (ez + emz) * -1.0i;
+ __imag__ res = __copysignl (1.0, __imag__ x);
+ __real__ res = 4 * sinrx * cosrx;
+ __imag__ x = fabsl (__imag__ x);
+ __imag__ x -= t;
+ __real__ res /= exp_2t;
+ if (__imag__ x > t)
+ {
+ /* Underflow (original imaginary part of x has absolute
+ value > 2t). */
+ __real__ res /= exp_2t;
+ }
+ else
+ __real__ res /= __ieee754_expl (2 * __imag__ x);
}
else
{
- __real__ res = sin2rx / den;
- __imag__ res = __ieee754_sinhl (2.0 * __imag__ x) / den;
+ long double sinhix = __ieee754_sinhl (__imag__ x);
+ long double coshix = __ieee754_coshl (__imag__ x);
+
+ den = cosrx * cosrx + sinhix * sinhix;
+ __real__ res = sinrx * cosrx / den;
+ __imag__ res = sinhix * coshix / den;
}
+
/* __gcc_qmul does not respect -0.0 so we need the following fixup. */
if ((__real__ res == 0.0) && (__real__ x == 0.0))
__real__ res = __real__ x;
diff --git a/sysdeps/powerpc/fpu/libm-test-ulps b/sysdeps/powerpc/fpu/libm-test-ulps
index c555297..43fa642 100644
--- a/sysdeps/powerpc/fpu/libm-test-ulps
+++ b/sysdeps/powerpc/fpu/libm-test-ulps
@@ -1051,16 +1051,44 @@ ifloat: 2
# ctan
Test "Real part of: ctan (-2 - 3 i) == 0.376402564150424829275122113032269084e-2 - 1.00323862735360980144635859782192726 i":
+float: 1
+ifloat: 1
double: 1
idouble: 1
+ldouble: 1
+ildouble: 1
+Test "Real part of: ctan (1 + 47 i) == 2.729321264492904590777293425576722354636e-41 + 1.0 i":
+ldouble: 2
+ildouble: 2
Test "Imaginary part of: ctan (-2 - 3 i) == 0.376402564150424829275122113032269084e-2 - 1.00323862735360980144635859782192726 i":
+double: 1
+idouble: 1
ildouble: 1
ldouble: 1
+Test "Real part of: ctan (0.75 + 1.25 i) == 0.160807785916206426725166058173438663 + 0.975363285031235646193581759755216379 i":
+float: 1
+ifloat: 1
Test "Imaginary part of: ctan (0.75 + 1.25 i) == 0.160807785916206426725166058173438663 + 0.975363285031235646193581759755216379 i":
+float: 1
+ifloat: 1
double: 1
idouble: 1
ildouble: 1
ldouble: 1
+Test "Real part of: ctan (0x1p1023 + 1 i) == -0.2254627924997545057926782581695274244229 + 0.8786063118883068695462540226219865087189 i":
+double: 1
+idouble: 1
+Test "Real part of: ctan (0x1p127 + 1 i) == 0.2446359391192790896381501310437708987204 + 0.9101334047676183761532873794426475906201 i":
+float: 1
+ifloat: 1
+Test "Imaginary part of: ctan (0x1p127 + 1 i) == 0.2446359391192790896381501310437708987204 + 0.9101334047676183761532873794426475906201 i":
+float: 1
+ifloat: 1
+double: 1
+idouble: 1
+Test "Real part of: ctan (0x3.243f6cp-1 + 0 i) == -2.287733242885645987394874673945769518150e7 + 0.0 i":
+float: 1
+ifloat: 1
# ctanh
Test "Real part of: ctanh (-2 - 3 i) == -0.965385879022133124278480269394560686 + 0.988437503832249372031403430350121098e-2 i":
@@ -1068,14 +1096,43 @@ double: 1
float: 2
idouble: 1
ifloat: 2
+Test "Imaginary part of: ctanh (-2 - 3 i) == -0.965385879022133124278480269394560686 + 0.988437503832249372031403430350121098e-2 i":
+double: 1
+idouble: 1
Test "Imaginary part of: ctanh (0 + pi/4 i) == 0.0 + 1.0 i":
float: 1
ifloat: 1
+double: 1
+idouble: 1
Test "Real part of: ctanh (0.75 + 1.25 i) == 1.37260757053378320258048606571226857 + 0.385795952609750664177596760720790220 i":
double: 1
idouble: 1
ildouble: 1
-ldouble: 1
+ldouble: 3
+ildouble: 3
+Test "Imaginary part of: ctanh (0.75 + 1.25 i) == 1.37260757053378320258048606571226857 + 0.385795952609750664177596760720790220 i":
+float: 1
+ifloat: 1
+ldouble: 2
+ildouble: 2
+Test "Imaginary part of: ctanh (47 + 1 i) == 1.0 + 2.729321264492904590777293425576722354636e-41 i":
+ldouble: 2
+ildouble: 2
+Test "Imaginary part of: ctanh (0 + 0x3.243f6cp-1 i) == 0.0 - 2.287733242885645987394874673945769518150e7 i":
+float: 1
+ifloat: 1
+Test "Imaginary part of: ctanh (1 + 0x1p1023 i) == 0.8786063118883068695462540226219865087189 - 0.2254627924997545057926782581695274244229 i":
+double: 1
+idouble: 1
+Test "Real part of: ctanh (1 + 0x1p127 i) == 0.9101334047676183761532873794426475906201 + 0.2446359391192790896381501310437708987204 i":
+float: 1
+ifloat: 1
+double: 1
+idouble: 1
+Test "Imaginary part of: ctanh (1 + 0x1p127 i) == 0.9101334047676183761532873794426475906201 + 0.2446359391192790896381501310437708987204 i":
+float: 1
+ifloat: 1
+double: 1
# erf
Test "erf (1.25) == 0.922900128256458230136523481197281140":
@@ -2309,12 +2366,16 @@ ildouble: 1
ldouble: 1
Function: Real part of "ctan":
+float: 1
+ifloat: 1
double: 1
idouble: 1
-ildouble: 1
-ldouble: 1
+ildouble: 2
+ldouble: 2
Function: Imaginary part of "ctan":
+float: 1
+ifloat: 1
double: 1
idouble: 1
ildouble: 1
@@ -2325,14 +2386,16 @@ double: 1
float: 2
idouble: 1
ifloat: 2
-ildouble: 1
-ldouble: 1
+ildouble: 3
+ldouble: 3
Function: Imaginary part of "ctanh":
float: 1
ifloat: 1
-ildouble: 1
-ldouble: 1
+double: 1
+idouble: 1
+ildouble: 2
+ldouble: 2
Function: "erf":
double: 1