Rearrange the polynomial evaluation for better parallelism. This

saves an average of about 8 cycles or 5% on A64 (amd64 and i386 --
more in cycles but about the same percentage on i386, and more with
old versions of gcc) with good CFLAGS and some parallelism in the
caller.  As usual, it takes a couple more multiplications so it will
be slower on old machines.

Convert to __FBSDID().

2 files changed, 9 insertions, 9 deletions

diff --git a/lib/msun/src/k_cos.c b/lib/msun/src/k_cos.c
index 9933bf3..c4702e6 100644
--- a/lib/msun/src/k_cos.c
+++ b/lib/msun/src/k_cos.c
@@ -11,9 +11,8 @@
  * ====================================================
  */
 
-#ifndef lint
-static char rcsid[] = "$FreeBSD$";
-#endif
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
 
 /*
  * __kernel_cos( x,  y )
@@ -72,7 +71,8 @@ __kernel_cos(double x, double y)
 	double hz,z,r,w;
 
 	z  = x*x;
-	r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
+	w  = z*z;
+	r  = z*(C1+z*(C2+z*C3)) + w*w*(C4+z*(C5+z*C6));
 	hz = 0.5*z;
 	w  = one-hz;
 	return w + (((one-w)-hz) + (z*r-x*y));
diff --git a/lib/msun/src/k_sin.c b/lib/msun/src/k_sin.c
index fe2a56c..12ee8c1 100644
--- a/lib/msun/src/k_sin.c
+++ b/lib/msun/src/k_sin.c
@@ -11,9 +11,8 @@
  * ====================================================
  */
 
-#ifndef lint
-static char rcsid[] = "$FreeBSD$";
-#endif
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
 
 /* __kernel_sin( x, y, iy)
  * kernel sin function on ~[-pi/4, pi/4] (except on -0), pi/4 ~ 0.7854
@@ -60,11 +59,12 @@ S6  =  1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */
 double
 __kernel_sin(double x, double y, int iy)
 {
-	double z,r,v;
+	double z,r,v,w;
 
 	z	=  x*x;
+	w	=  z*z;
+	r	=  S2+z*(S3+z*S4) + z*w*(S5+z*S6);
 	v	=  z*x;
-	r	=  S2+z*(S3+z*(S4+z*(S5+z*S6)));
 	if(iy==0) return x+v*(S1+z*r);
 	else      return x-((z*(half*y-v*r)-y)-v*S1);
 }