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Fix ctan, ctanh of subnormals in round-upwards mode (bug 14328).
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IBM long double fixes and POWER ulps update.
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Adhemerval Zanella committed Jul 11, 2012
1 parent 6b90f98 commit 28cfe84
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Showing 4 changed files with 331 additions and 23 deletions.
7 changes: 7 additions & 0 deletions ChangeLog
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Original file line number Diff line number Diff line change
@@ -1,3 +1,10 @@
2012-07-11 Adhemerval Zanella <azanella@linux.vnet.ibm.com>

* sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c: Do not call sinh and cosh
for subnormals or multiply small sinh result by itself.
* sysdeps/ieee754/ldbl-128ibm/s_ctanl.c: Likewise.
* sysdeps/powerpc/fpu/libm-test-ulps: Update.

2012-07-11 David S. Miller <davem@davemloft.net>

* sysdeps/sparc/fpu/libm-test-ulps: Update.
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38 changes: 26 additions & 12 deletions sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@

#include <math_private.h>

/* IBM long double GCC builtin sets LDBL_EPSILON == LDBL_DENORM_MIN */
static const long double ldbl_eps = 0x1p-106L;

__complex__ long double
__ctanhl (__complex__ long double x)
Expand All @@ -35,8 +37,8 @@ __ctanhl (__complex__ long double x)
{
if (__isinfl (__real__ x))
{
__real__ res = __copysignl (1.0, __real__ x);
__imag__ res = __copysignl (0.0, __imag__ x);
__real__ res = __copysignl (1.0L, __real__ x);
__imag__ res = __copysignl (0.0L, __imag__ x);
}
else if (__imag__ x == 0.0)
{
Expand All @@ -57,7 +59,7 @@ __ctanhl (__complex__ long double x)
{
long double sinix, cosix;
long double den;
const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2);
const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2.0L);

/* 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). */
Expand All @@ -71,7 +73,7 @@ __ctanhl (__complex__ long double x)
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);
__real__ res = __copysignl (1.0L, __real__ x);
__imag__ res = 4 * sinix * cosix;
__real__ x = fabsl (__real__ x);
__real__ x -= t;
Expand All @@ -83,22 +85,34 @@ __ctanhl (__complex__ long double x)
__imag__ res /= exp_2t;
}
else
__imag__ res /= __ieee754_expl (2 * __real__ x);
__imag__ res /= __ieee754_expl (2.0L * __real__ x);
}
else
{
long double sinhrx = __ieee754_sinhl (__real__ x);
long double coshrx = __ieee754_coshl (__real__ x);
long double sinhrx, coshrx;
if (fabs (__real__ x) > LDBL_MIN)
{
sinhrx = __ieee754_sinhl (__real__ x);
coshrx = __ieee754_coshl (__real__ x);
}
else
{
sinhrx = __real__ x;
coshrx = 1.0L;
}

den = sinhrx * sinhrx + cosix * cosix;
__real__ res = sinhrx * coshrx / den;
__imag__ res = sinix * cosix / den;
if (fabsl (sinhrx) > fabsl (cosix) * ldbl_eps)
den = sinhrx * sinhrx + cosix * cosix;
else
den = 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))
if ((__real__ res == 0.0L) && (__real__ x == 0.0L))
__real__ res = __real__ x;

if ((__real__ res == 0.0) && (__imag__ x == 0.0))
if ((__real__ res == 0.0L) && (__imag__ x == 0.0L))
__imag__ res = __imag__ x;
}

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34 changes: 24 additions & 10 deletions sysdeps/ieee754/ldbl-128ibm/s_ctanl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,8 @@

#include <math_private.h>

/* IBM long double GCC builtin sets LDBL_EPSILON == LDBL_DENORM_MIN */
static const long double ldbl_eps = 0x1p-106L;

__complex__ long double
__ctanl (__complex__ long double x)
Expand Down Expand Up @@ -55,7 +57,7 @@ __ctanl (__complex__ long double x)
{
long double sinrx, cosrx;
long double den;
const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2);
const int t = (int) ((LDBL_MAX_EXP - 1) * M_LN2l / 2.0L);

/* 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). */
Expand All @@ -70,7 +72,7 @@ __ctanl (__complex__ long double x)
sin(x)*cos(x)/sinh(y)^2 = 4*sin(x)*cos(x)/exp(2y). */
long double exp_2t = __ieee754_expl (2 * t);

__imag__ res = __copysignl (1.0, __imag__ x);
__imag__ res = __copysignl (1.0L, __imag__ x);
__real__ res = 4 * sinrx * cosrx;
__imag__ x = fabsl (__imag__ x);
__imag__ x -= t;
Expand All @@ -82,23 +84,35 @@ __ctanl (__complex__ long double x)
__real__ res /= exp_2t;
}
else
__real__ res /= __ieee754_expl (2 * __imag__ x);
__real__ res /= __ieee754_expl (2.0L * __imag__ x);
}
else
{
long double sinhix = __ieee754_sinhl (__imag__ x);
long double coshix = __ieee754_coshl (__imag__ x);
long double sinhix, coshix;
if (fabsl (__imag__ x) > LDBL_MIN)
{
sinhix = __ieee754_sinhl (__imag__ x);
coshix = __ieee754_coshl (__imag__ x);
}
else
{
sinhix = __imag__ x;
coshix = 1.0L;
}

den = cosrx * cosrx + sinhix * sinhix;
__real__ res = sinrx * cosrx / den;
__imag__ res = sinhix * coshix / den;
if (fabsl (sinhix) > fabsl (cosrx) * ldbl_eps)
den = cosrx * cosrx + sinhix * sinhix;
else
den = cosrx * cosrx;
__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))
if ((__real__ res == 0.0L) && (__real__ x == 0.0L))
__real__ res = __real__ x;

if ((__real__ res == 0.0) && (__imag__ x == 0.0))
if ((__real__ res == 0.0L) && (__imag__ x == 0.0L))
__imag__ res = __imag__ x;
}

Expand Down
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