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s_sinf.c: Replace floor with simple casts

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Since s_sinf.c either assigns the return value of floor to integer or
passes double converted from integer to floor, this patch replaces
floor with simple casts.

Also since long == int for 32-bit targets, we can use long instead of
int to avoid 64-bit integer for 64-bit targets.

On Skylake, bench-sinf reports performance improvement:

           Before        After         Improvement
max        130.566       129.564           30%
min        7.704         7.706             0%
mean       21.8188       19.1363           30%

	* sysdeps/ieee754/flt-32/s_sinf.c (reduced): Replace long with
	int.
	(SINF_FUNC): Likewise.  Replace floor with simple casts.
This commit is contained in:
H.J. Lu 2017-12-05 08:32:19 -08:00
parent c7e882b705
commit 91c318e7b9
2 changed files with 12 additions and 6 deletions
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6
ChangeLog
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@ -1,3 +1,9 @@
2017-12-05 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/ieee754/flt-32/s_sinf.c (reduced): Replace long with
int.
(SINF_FUNC): Likewise. Replace floor with simple casts.
2017-12-05 Mike FABIAN <mfabian@redhat.com>
[BZ #22517]

12
sysdeps/ieee754/flt-32/s_sinf.c
View File

@ -85,8 +85,8 @@ static const int ones[] = { +1, -1 };
SIGNBIT is used to add the correct sign after the Chebyshev
polynomial is computed. */
static inline float
reduced (const double theta, const unsigned long int n,
const unsigned long int signbit)
reduced (const double theta, const unsigned int n,
const unsigned int signbit)
{
double sx;
const double theta2 = theta * theta;
@ -162,14 +162,14 @@ SINF_FUNC (float x)
}
else /* |x| >= Pi/4. */
{
unsigned long int signbit = (x < 0);
unsigned int signbit = (x < 0);
if (abstheta < 9 * M_PI_4) /* |x| < 9*Pi/4. */
{
/* There are cases where FE_UPWARD rounding mode can
produce a result of abstheta * inv_PI_4 == 9,
where abstheta < 9pi/4, so the domain for
pio2_table must go to 5 (9 / 2 + 1). */
unsigned long int n = (abstheta * inv_PI_4) + 1;
unsigned int n = (abstheta * inv_PI_4) + 1;
theta = abstheta - pio2_table[n / 2];
return reduced (theta, n, signbit);
}
@ -177,8 +177,8 @@ SINF_FUNC (float x)
{
if (abstheta < 0x1p+23) /* |x| < 2^23. */
{
unsigned long int n = __floor (abstheta * inv_PI_4) + 1.0;
double x = __floor (n / 2.0);
unsigned int n = ((unsigned int) (abstheta * inv_PI_4)) + 1;
double x = n / 2;
theta = x * PI_2_lo + (x * PI_2_hi + abstheta);
/* Argument reduction needed. */
return reduced (theta, n, signbit);