diff --git a/lisp/php.el b/lisp/php.el
index ffb6cfbf..28fa97f5 100644
--- a/lisp/php.el
+++ b/lisp/php.el
@@ -223,7 +223,17 @@ it is the character that will terminate the string, or t if the string should be
   (bound-and-true-p poly-php-html-mode))
 
 (defconst php-beginning-of-defun-regexp
-  "^\\s-*\\(?:\\(?:abstract\\|final\\|private\\|protected\\|public\\|static\\)\\s-+\\)*function\\s-+&?\\(\\(\\sw\\|\\s_\\)+\\)\\s-*("
+  (eval-when-compile
+    (rx bol
+        (* (syntax whitespace))
+        (* (or "abstract" "final" "private" "protected" "public" "static")
+           (+ (syntax whitespace)))
+        "function"
+        (+ (syntax whitespace))
+        (? "&" (* (syntax whitespace)))
+        (group (+ (or (syntax word) (syntax symbol))))
+        (* (syntax whitespace))
+        "("))
   "Regular expression for a PHP function.")
 
 (eval-when-compile