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, 39 insertions, 38 deletions

diff --git a/log1p.c b/log1p.c
index 7bd641f7a..9e831da2b 100644
--- a/log1p.c
+++ b/log1p.c
@@ -34,53 +34,54 @@ mpfr_log1p (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
 {
   int comp, 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 (result is not defined) */
-  if (MPFR_IS_INF(x))
-    {
-      if (MPFR_SIGN(x) > 0)
-        {
-          MPFR_SET_INF(y);
-          MPFR_SET_POS(y);
-          MPFR_RET(0);
-        }
-      else
-        {
-          MPFR_SET_NAN(y);
-          MPFR_RET_NAN;
-        }
+      if (MPFR_IS_NAN(x)) 
+	{
+	  MPFR_SET_NAN(y); 
+	  MPFR_RET_NAN;
+	}
+      MPFR_CLEAR_NAN(y);      
+      /* check for inf or -inf (result is not defined) */
+      if (MPFR_IS_INF(x))
+	{
+	  if (MPFR_IS_POS(x))
+	    {
+	      MPFR_SET_INF(y);
+	      MPFR_SET_POS(y);
+	      MPFR_RET(0);
+	    }
+	  else
+	    {
+	      MPFR_SET_NAN(y);
+	      MPFR_RET_NAN;
+	    }
+	}
+      if (MPFR_IS_ZERO(x))
+	{
+	  MPFR_SET_ZERO(y);   /* log1p(+/- 0) = +/- 0 */
+	  MPFR_SET_SAME_SIGN(y, x);
+	  MPFR_RET(0);
+	}
+      MPFR_ASSERTN(1);
     }
-
+  
   comp = mpfr_cmp_si(x,-1);
   /* x<-1 undefined */
-  if (comp < 0) 
+  if (MPFR_UNLIKELY(comp <= 0)) 
     {
+      if (comp == 0)
+	/* x=0: log1p(-1)=-inf (division by zero) */
+	{
+	  MPFR_SET_INF(y);
+	  MPFR_SET_POS(y);
+	  MPFR_RET_NAN;
+	}
       MPFR_SET_NAN(y);
       MPFR_RET_NAN;
     }
-  /* x=0: log1p(-1)=-inf (division by zero) */
-  if (comp == 0)
-    {
-      MPFR_SET_INF(y);
-      MPFR_SET_POS(y);
-      MPFR_RET_NAN;
-    }
 
-  MPFR_CLEAR_INF(y);
-
-  if (MPFR_IS_ZERO(x))
-    {
-      MPFR_SET_ZERO(y);   /* log1p(+/- 0) = +/- 0 */
-      MPFR_SET_SAME_SIGN(y, x);
-      MPFR_RET(0);
-    }
+  MPFR_CLEAR_FLAGS(y);
 
   /* General case */
   {