From: Siddhesh Poyarekar <siddhesh@redhat.com>
Date: Wed, 13 Feb 2013 11:49:06 +0000 (+0530)
Subject: Remove unnecessary factorial array
X-Git-Tag: upstream/2.30~9527
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c2af38aa768d1c24b24ba1bed473aaee6c2d675e;p=external%2Fglibc.git

Remove unnecessary factorial array

kf is n! at the end of the loop, so storing the values is unnecessary.
---

diff --git a/ChangeLog b/ChangeLog
index 07ad26f..ed911fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2013-02-13  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
+	* sysdeps/ieee754/dbl-64/mpexp.c (__mpexp): Remove NFA.
+
 	* sysdeps/ieee754/dbl-64/mpexp.c (__mpexp): Faster polynomial
 	evaluation.
 
diff --git a/sysdeps/ieee754/dbl-64/mpexp.c b/sysdeps/ieee754/dbl-64/mpexp.c
index 35c4e80..5b3ff04 100644
--- a/sysdeps/ieee754/dbl-64/mpexp.c
+++ b/sysdeps/ieee754/dbl-64/mpexp.c
@@ -50,14 +50,6 @@ __mpexp (mp_no *x, mp_no *y, int p)
       6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8
     };
 
-  /* Factorials for the values of np above.  */
-  static const double nfa[33] =
-    {
-      1.0, 1.0, 1.0, 1.0, 6.0, 6.0, 24.0, 24.0, 120.0, 24.0, 24.0,
-      120.0, 120.0, 120.0, 720.0, 720.0, 720.0, 720.0, 720.0, 720.0,
-      720.0, 720.0, 720.0, 720.0, 5040.0, 5040.0, 5040.0, 5040.0,
-      40320.0, 40320.0, 40320.0, 40320.0, 40320.0
-    };
   static const int m1p[33] =
     {
       0, 0, 0, 0,
@@ -130,7 +122,8 @@ __mpexp (mp_no *x, mp_no *y, int p)
          e^x = 1 + (x * n!/1! + x^2 * n!/2! + x^3 * n!/3!) / n!
              = 1 + (x * (n!/1! + x * (n!/2! + x * (n!/3! + x ...)))) / n!
 
-     n! is pre-computed and saved while k! is computed on the fly.  */
+     k! is computed on the fly as KF and at the end of the polynomial loop, KF
+     is n!, which can be used directly.  */
   __cpy (&mps, &mpt2, p);
 
   double kf = 1.0;
@@ -145,7 +138,7 @@ __mpexp (mp_no *x, mp_no *y, int p)
       __add (&mpt2, &mpk, &mpt1, p);
       __mul (&mps, &mpt1, &mpt2, p);
     }
-  __dbl_mp (nfa[p], &mpk, p);
+  __dbl_mp (kf, &mpk, p);
   __dvd (&mpt2, &mpk, &mpt1, p);
   __add (&mpone, &mpt1, &mpt2, p);