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, 26 insertions, 27 deletions

diff --git a/expm1.c b/expm1.c
index 4d8039ccc..89cec929b 100644
--- a/expm1.c
+++ b/expm1.c
@@ -34,34 +34,33 @@ mpfr_expm1 (mpfr_ptr y, mpfr_srcptr x , mp_rnd_t rnd_mode)
 {
   int inexact = 0;
 
-  if (MPFR_IS_NAN(x))
+  if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(x) ))
     {
-      MPFR_SET_NAN(y);
-      MPFR_RET_NAN;
-    }
-
-  MPFR_CLEAR_NAN(y);
-
-  /* check for inf or -inf (expm1(-inf)=-1) */
-  if (MPFR_IS_INF(x))
-    { 
-      if (MPFR_SIGN(x) > 0)
-        {
-          MPFR_SET_INF(y);
-          MPFR_SET_POS(y);
-          return 0;
-        }
-      else
-        return mpfr_set_si(y, -1, rnd_mode);
-    }
-
-  MPFR_CLEAR_INF(y);
-
-  if(MPFR_IS_ZERO(x))
-    {
-      MPFR_SET_ZERO(y);   /* expm1(+/- 0) = +/- 0 */
-      MPFR_SET_SAME_SIGN(y,x);
-      MPFR_RET(0);
+      if (MPFR_IS_NAN(x))
+	{
+	  MPFR_SET_NAN(y);
+	  MPFR_RET_NAN;
+	}
+      MPFR_CLEAR_NAN(y);
+      /* check for inf or -inf (expm1(-inf)=-1) */
+      if (MPFR_IS_INF(x))
+	{ 
+	  if (MPFR_IS_POS(x))
+	    {
+	      MPFR_SET_INF(y);
+	      MPFR_SET_POS(y);
+	      return 0;
+	    }
+	  else
+	    return mpfr_set_si(y, -1, rnd_mode);
+	}
+      MPFR_CLEAR_INF(y);
+      if(MPFR_IS_ZERO(x))
+	{
+	  MPFR_SET_ZERO(y);   /* expm1(+/- 0) = +/- 0 */
+	  MPFR_SET_SAME_SIGN(y,x);
+	  MPFR_RET(0);
+	}
     }
 
   /* General case */