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Remove some redundant computations in s_sin.c

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There are multiple points in the code where the absolute value of a
number is computed multiple times or is computed even though the value
can only be positive.  This change removes those redundant
computations.  Tested on x86_64 to verify that there were no
regressions in the testsuite.
This commit is contained in:
Siddhesh Poyarekar 2013-12-20 15:55:34 +05:30
parent 64a17f1add
commit 5ff8d60ef3
2 changed files with 24 additions and 24 deletions
ChangeLog
sysdeps/ieee754/dbl-64
s_sin.c

9
ChangeLog

@ -1,3 +1,12 @@
2013-12-20 Siddhesh Poyarekar <siddhesh@redhat.com>
* sysdeps/ieee754/dbl-64/s_sin.c (__sin): Use DA directly.
(__cos): Likewise.
(sloww1): Don't adjust sign of DX.
(csloww1): Likewise.
(sloww2): Use X directly and don't adjust sign of DX.
(csloww2): Likewise.
2013-12-19 Joseph Myers <joseph@codesourcery.com>
* math/auto-libm-test-in: Add tests of cabs and carg.

39
sysdeps/ieee754/dbl-64/s_sin.c

@ -290,19 +290,18 @@ __sin (double x)
{
m = 1;
t = a;
db = da;
}
else
{
m = 0;
t = -a;
db = -da;
da = -da;
}
u.x = big + t;
y = t - (u.x - big);
xx = y * y;
s = y + (db + y * xx * (sn3 + xx * sn5));
c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6));
s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
SINCOS_TABLE_LOOKUP (u, sn, ssn, cs, ccs);
cor = (ssn + s * ccs - sn * c) + cs * s;
res = sn + cor;
@ -498,19 +497,18 @@ __cos (double x)
{
m = 1;
t = a;
db = da;
}
else
{
m = 0;
t = -a;
db = -da;
da = -da;
}
u.x = big + t;
y = t - (u.x - big);
xx = y * y;
s = y + (db + y * xx * (sn3 + xx * sn5));
c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6));
s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
SINCOS_TABLE_LOOKUP (u, sn, ssn, cs, ccs);
cor = (ssn + s * ccs - sn * c) + cs * s;
res = sn + cor;
@ -557,19 +555,18 @@ __cos (double x)
{
m = 1;
t = a;
db = da;
}
else
{
m = 0;
t = -a;
db = -da;
da = -da;
}
u.x = big + t;
y = t - (u.x - big);
xx = y * y;
s = y + (db + y * xx * (sn3 + xx * sn5));
c = y * db + xx * (cs2 + xx * (cs4 + xx * cs6));
s = y + (da + y * xx * (sn3 + xx * sn5));
c = y * da + xx * (cs2 + xx * (cs4 + xx * cs6));
SINCOS_TABLE_LOOKUP (u, sn, ssn, cs, ccs);
cor = (ssn + s * ccs - sn * c) + cs * s;
res = sn + cor;
@ -899,7 +896,6 @@ sloww1 (double x, double dx, double orig)
y = ABS (x);
u.x = big + y;
y = y - (u.x - big);
dx = (x > 0) ? dx : -dx;
xx = y * y;
s = y * xx * (sn3 + xx * sn5);
c = xx * (cs2 + xx * (cs4 + xx * cs6));
@ -951,10 +947,8 @@ sloww2 (double x, double dx, double orig, int n)
mynumber u;
double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, e1, e2, xx, cor, res;
y = ABS (x);
u.x = big + y;
y = y - (u.x - big);
dx = (x > 0) ? dx : -dx;
u.x = big + x;
y = x - (u.x - big);
xx = y * y;
s = y * xx * (sn3 + xx * sn5);
c = y * dx + xx * (cs2 + xx * (cs4 + xx * cs6));
@ -979,7 +973,7 @@ sloww2 (double x, double dx, double orig, int n)
return (n & 2) ? -res : res;
else
{
__docos (ABS (x), dx, w);
__docos (x, dx, w);
if (w[1] > 0)
cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig);
@ -1254,7 +1248,6 @@ csloww1 (double x, double dx, double orig)
y = ABS (x);
u.x = big + y;
y = y - (u.x - big);
dx = (x > 0) ? dx : -dx;
xx = y * y;
s = y * xx * (sn3 + xx * sn5);
c = xx * (cs2 + xx * (cs4 + xx * cs6));
@ -1305,10 +1298,8 @@ csloww2 (double x, double dx, double orig, int n)
mynumber u;
double sn, ssn, cs, ccs, s, c, w[2], y, y1, y2, e1, e2, xx, cor, res;
y = ABS (x);
u.x = big + y;
y = y - (u.x - big);
dx = (x > 0) ? dx : -dx;
u.x = big + x;
y = x - (u.x - big);
xx = y * y;
s = y * xx * (sn3 + xx * sn5);
c = y * dx + xx * (cs2 + xx * (cs4 + xx * cs6));
@ -1333,7 +1324,7 @@ csloww2 (double x, double dx, double orig, int n)
return (n) ? -res : res;
else
{
__docos (ABS (x), dx, w);
__docos (x, dx, w);
if (w[1] > 0)
cor = 1.000000005 * w[1] + 1.1e-30 * ABS (orig);
else