issue23591: optimize _high_bit()
diff --git a/Lib/enum.py b/Lib/enum.py
index 8369631..8d23933 100644
--- a/Lib/enum.py
+++ b/Lib/enum.py
@@ -784,13 +784,8 @@
def _high_bit(value):
- """return the highest bit set in value"""
- bit = 0
- while 'looking for the highest bit':
- limit = 2 ** bit
- if limit > value:
- return bit - 1
- bit += 1
+ """returns index of highest bit, or -1 if value is zero or negative"""
+ return value.bit_length() - 1 if value > 0 else -1
def unique(enumeration):
"""Class decorator for enumerations ensuring unique member values."""