1 files changed, 3 insertions, 6 deletions
diff --git a/activesupport/lib/active_support/core_ext/object/blank.rb b/activesupport/lib/active_support/core_ext/object/blank.rb
index 71d411b6d6..f7efa1e01a 100644
--- a/activesupport/lib/active_support/core_ext/object/blank.rb
+++ b/activesupport/lib/active_support/core_ext/object/blank.rb
@@ -112,12 +112,9 @@ class String
   #
   # @return [true, false]
   def blank?
-    # In practice, the majority of blank strings are empty. As of this writing
-    # checking for empty? is about 3.5x faster than matching against the regexp
-    # in MRI, so we call the predicate first, and then fallback.
-    #
-    # The penalty for blank strings with whitespace or present ones is marginal.
-    empty? || BLANK_RE === self
+    # Regex check is slow, only check non-empty strings.
+    # A string not blank if it contains a single non-space string.
+    empty? || !(/[[:^space:]]/ === self)
   end
 end