Optimize libm

[thirdparty/glibc.git] / math / w_exp2f.c

diff --git a/math/w_exp2f.c b/math/w_exp2f.c
index 94c82e206e0039af877af030ed8c42b57bc46ec0..7215fcaf4cb99a3b183a7ab06300d97437cc439f 100644 (file)
--- a/math/w_exp2f.c
+++ b/math/w_exp2f.c
@@ -6,27 +6,17 @@
 #include <math.h>
 #include <math_private.h>
 
-static const float o_threshold= (float) FLT_MAX_EXP;
-static const float u_threshold= (float) (FLT_MIN_EXP - FLT_MANT_DIG - 1);
+static const float o_threshold = (float) FLT_MAX_EXP;
+static const float u_threshold = (float) (FLT_MIN_EXP - FLT_MANT_DIG - 1);
 
 float
-__exp2f (float x)              /* wrapper exp2f */
+__exp2f (float x)
 {
-#ifdef _IEEE_LIBM
+  if (__builtin_expect (x <= u_threshold || x > o_threshold, 0)
+      && _LIB_VERSION != _IEEE_ && __finitef (x))
+    /* exp2 overflow: 144, exp2 underflow: 145 */
+    return __kernel_standard_f (x, x, 144 + (x <= o_threshold));
+
   return __ieee754_exp2f (x);
-#else
-  float z;
-  z = __ieee754_exp2f (x);
-  if (_LIB_VERSION != _IEEE_ && __finitef (x))
-    {
-      if (x > o_threshold)
-       /* exp2 overflow */
-       return (float) __kernel_standard ((double) x, (double) x, 144);
-      else if (x <= u_threshold)
-       /* exp2 underflow */
-       return (float) __kernel_standard ((double) x, (double) x, 145);
-    }
-  return z;
-#endif
 }
 weak_alias (__exp2f, exp2f)