4 files changed, 14 insertions, 46 deletions

diff --git a/lib/msun/src/k_tan.c b/lib/msun/src/k_tan.c
index 15145a6..13737d0 100644
--- a/lib/msun/src/k_tan.c
+++ b/lib/msun/src/k_tan.c
@@ -16,14 +16,16 @@ static char rcsid[] = "$FreeBSD$";
 #endif
 
 /* __kernel_tan( x, y, k )
- * kernel tan function on [-pi/4, pi/4], pi/4 ~ 0.7854
+ * kernel tan function on ~[-pi/4, pi/4] (except on -0), pi/4 ~ 0.7854
  * Input x is assumed to be bounded by ~pi/4 in magnitude.
  * Input y is the tail of x.
  * Input k indicates whether tan (if k = 1) or -1/tan (if k = -1) is returned.
  *
  * Algorithm
  *	1. Since tan(-x) = -tan(x), we need only to consider positive x.
- *	2. if x < 2^-28 (hx<0x3e300000 0), return x with inexact if x!=0.
+ *	2. Callers must return tan(-0) = -0 without calling here since our
+ *	   odd polynomial is not evaluated in a way that preserves -0.
+ *	   Callers may do the optimization tan(x) ~ x for tiny x.
  *	3. tan(x) is approximated by a odd polynomial of degree 27 on
  *	   [0,0.67434]
  *		  	         3             27
@@ -81,27 +83,6 @@ __kernel_tan(double x, double y, int iy) {
 
 	GET_HIGH_WORD(hx,x);
 	ix = hx & 0x7fffffff;			/* high word of |x| */
-	if (ix < 0x3e300000) {			/* x < 2**-28 */
-		if ((int) x == 0) {		/* generate inexact */
-			u_int32_t low;
-			GET_LOW_WORD(low,x);
-			{
-				if (iy == 1)
-					return x;
-				else {	/* compute -1 / (x+y) carefully */
-					double a, t;
-
-					z = w = x + y;
-					SET_LOW_WORD(z, 0);
-					v = y - (z - x);
-					t = a = -one / w;
-					SET_LOW_WORD(t, 0);
-					s = one + t * z;
-					return t + a * (s + t * v);
-				}
-			}
-		}
-	}
 	if (ix >= 0x3FE59428) {	/* |x| >= 0.6744 */
 		if (hx < 0) {
 			x = -x;
diff --git a/lib/msun/src/k_tanf.c b/lib/msun/src/k_tanf.c
index e344787..8e19309 100644
--- a/lib/msun/src/k_tanf.c
+++ b/lib/msun/src/k_tanf.c
@@ -45,27 +45,6 @@ __kernel_tanf(float x, float y, int iy)
 	int32_t ix,hx;
 	GET_FLOAT_WORD(hx,x);
 	ix = hx&0x7fffffff;	/* high word of |x| */
-	if(ix<0x31800000) {			/* x < 2**-28 */
-		if ((int) x == 0) {		/* generate inexact */
-			{
-				if (iy == 1)
-					return x;
-				else {	/* compute -1 / (x+y) carefully */
-					float a, t;
-
-					z = w = x + y;
-					GET_FLOAT_WORD(ix, z);
-					SET_FLOAT_WORD(z, ix & 0xfffff000);
-					v = y - (z - x);
-					t = a = -one / w;
-					GET_FLOAT_WORD(ix, t);
-					SET_FLOAT_WORD(t, ix & 0xfffff000);
-					s = one + t * z;
-					return t + a * (s + t * v);
-				}
-			}
-		}
-	}
 	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
 	    if(hx<0) {x = -x; y = -y;}
 	    z = pio4-x;
diff --git a/lib/msun/src/s_tan.c b/lib/msun/src/s_tan.c
index 5094d30..d707ecd 100644
--- a/lib/msun/src/s_tan.c
+++ b/lib/msun/src/s_tan.c
@@ -58,7 +58,11 @@ tan(double x)
 
     /* |x| ~< pi/4 */
 	ix &= 0x7fffffff;
-	if(ix <= 0x3fe921fb) return __kernel_tan(x,z,1);
+	if(ix <= 0x3fe921fb) {
+	    if(ix<0x3e300000)			/* x < 2**-28 */
+		if((int)x==0) return x;		/* generate inexact */
+	    return __kernel_tan(x,z,1);
+	}
 
     /* tan(Inf or NaN) is NaN */
 	else if (ix>=0x7ff00000) return x-x;		/* NaN */
diff --git a/lib/msun/src/s_tanf.c b/lib/msun/src/s_tanf.c
index c81caaf..81c84e4 100644
--- a/lib/msun/src/s_tanf.c
+++ b/lib/msun/src/s_tanf.c
@@ -30,7 +30,11 @@ tanf(float x)
 
     /* |x| ~< pi/4 */
 	ix &= 0x7fffffff;
-	if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
+	if(ix <= 0x3f490fda) {
+	    if(ix<0x39800000)			/* |x| < 2**-12 */
+		if(((int)x)==0) return x;	/* generate inexact */
+	    return __kernel_tanf(x,z,1);
+	}
 
     /* tan(Inf or NaN) is NaN */
 	else if (ix>=0x7f800000) return x-x;		/* NaN */