Use of MPFR_UNLIKELY and MPFR_IS_SINGULAR for fast detection of special values (Nan, Inf or Zero).

Start to encapsulate the sign to be independant of the reprensation (Must be 1 or -1).


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2525 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 14 insertions, 13 deletions

diff --git a/erf.c b/erf.c
index 8499ab260..7f835e3fa 100644
--- a/erf.c
+++ b/erf.c
@@ -44,26 +44,27 @@ mpfr_erf (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
   double n = (double) MPFR_PREC(y);
   int inex;
 
-  if (MPFR_IS_NAN(x))
+  sign_x = MPFR_SIGN (x);
+  if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(x) ))
     {
-      MPFR_SET_NAN(y);
-      MPFR_RET_NAN;
+      if (MPFR_IS_NAN(x))
+	{
+	  MPFR_SET_NAN(y);
+	  MPFR_RET_NAN;
+	}
+      if (MPFR_IS_INF(x)) /* erf(+inf) = +1, erf(-inf) = -1 */
+	return mpfr_set_si (y, MPFR_FROM_SIGN_TO_INT(sign_x), GMP_RNDN);
+      if (MPFR_IS_ZERO(x)) /* erf(+0) = +0, erf(-0) = -0 */
+	return mpfr_set (y, x, GMP_RNDN); /* should keep the sign of x */
+      MPFR_ASSERTN(1);
     }
 
-  sign_x = MPFR_SIGN (x);
-
-  if (MPFR_IS_INF(x)) /* erf(+inf) = +1, erf(-inf) = -1 */
-    return mpfr_set_si (y, sign_x, GMP_RNDN);
-
-  if (MPFR_IS_ZERO(x)) /* erf(+0) = +0, erf(-0) = -0 */
-    return mpfr_set (y, x, GMP_RNDN); /* should keep the sign of x */
-
   /* now x is neither NaN, Inf nor 0 */
 
   xf = mpfr_get_d (x, GMP_RNDN);
   xf = xf * xf; /* xf ~ x^2 */
 
-  if (sign_x > 0)
+  if (MPFR_IS_POS_SIGN(sign_x))
     rnd2 = rnd_mode;
   else
     {
@@ -96,7 +97,7 @@ mpfr_erf (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
       inex = mpfr_erf_0 (y, x, rnd2);
     }
 
-  if (sign_x < 0)
+  if (MPFR_IS_NEG_SIGN(sign_x))
     {
       MPFR_CHANGE_SIGN (y);
       return - inex;