Optimize libm

libm is now somewhat integrated with gcc's -ffinite-math-only option
and lots of the wrapper functions have been optimized.

1 files changed, 34 insertions, 19 deletions

diff --git a/math/w_log2f.c b/math/w_log2f.c
index 10d73ffd1b..7c64ad8b81 100644
--- a/math/w_log2f.c
+++ b/math/w_log2f.c
@@ -1,30 +1,45 @@
-/*
- * wrapper log2(X)
- */
+/* Copyright (C) 2011 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
 
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <fenv.h>
 #include <math.h>
 #include <math_private.h>
 
+
+/* wrapper log2f(x) */
 float
-__log2f (float x)	/* wrapper log2f */
+__log2f (float x)
 {
-#ifdef _IEEE_LIBM
-  return __ieee754_log2f (x);
-#else
-  float z;
-  z = __ieee754_log2f (x);
-  if (_LIB_VERSION == _IEEE_ || __isnanf (x)) return z;
-  if (x <= 0.0f)
+  if (__builtin_expect (x <= 0.0f, 0) && _LIB_VERSION != _IEEE_)
     {
-      if (x == 0.0f)
-	/* log2f (0) */
-	return __kernel_standard ((double) x, (double) x, 148);
+      if (x == 0.0)
+	{
+	  feraiseexcept (FE_DIVBYZERO);
+	  return __kernel_standard_f (x, x, 148); /* log2(0) */
+	}
       else
-	/* log2f (x < 0) */
-	return __kernel_standard ((double) x, (double) x, 149);
+	{
+	  feraiseexcept (FE_INVALID);
+	  return __kernel_standard_f (x, x, 149); /* log2(x<0) */
+	}
     }
-  else
-    return z;
-#endif
+
+  return  __ieee754_log2f (x);
 }
 weak_alias (__log2f, log2f)