diff --git a/Zend/zend_arg_defs.c b/Zend/zend_arg_defs.c
index f1ce13a452d..be0601c9c82 100644
--- a/Zend/zend_arg_defs.c
+++ b/Zend/zend_arg_defs.c
@@ -40,6 +40,14 @@ ZEND_BEGIN_ARG_INFO(fourth_arg_force_ref, 0)
 	ZEND_ARG_PASS_INFO(1)
 ZEND_END_ARG_INFO();
 
+ZEND_BEGIN_ARG_INFO(fifth_arg_force_ref, 0)
+	ZEND_ARG_PASS_INFO(0)
+	ZEND_ARG_PASS_INFO(0)
+	ZEND_ARG_PASS_INFO(0)
+	ZEND_ARG_PASS_INFO(0)
+	ZEND_ARG_PASS_INFO(1)
+ZEND_END_ARG_INFO();
+
 ZEND_BEGIN_ARG_INFO(all_args_by_ref, 1)
 ZEND_END_ARG_INFO();
 
diff --git a/Zend/zend_modules.h b/Zend/zend_modules.h
index 8be64b5b018..57a38a82bb8 100644
--- a/Zend/zend_modules.h
+++ b/Zend/zend_modules.h
@@ -36,6 +36,7 @@ extern struct _zend_arg_info first_arg_force_ref[2];
 extern struct _zend_arg_info second_arg_force_ref[3];
 extern struct _zend_arg_info third_arg_force_ref[4];
 extern struct _zend_arg_info fourth_arg_force_ref[5];
+extern struct _zend_arg_info fifth_arg_force_ref[6];
 extern struct _zend_arg_info all_args_by_ref[1];
 
 #define ZEND_MODULE_API_NO 20050922
diff --git a/ext/pcre/TODO b/ext/pcre/TODO
new file mode 100644
index 00000000000..1000c64105f
--- /dev/null
+++ b/ext/pcre/TODO
@@ -0,0 +1,20 @@
+- Allow NULL for $matches argument (helps when using preg_match only for
+  match condition) - might not be possible
+
+- http://bugs.php.net/bug.php?id=36975
+
+- I'd love to see a pattern modifer which says "don't fill $matches except
+  for the overall match and any specific named captures". This would allow
+  (?: ...) to be avoided in a lot of cases.
+  
+  This could make for non-trivial speed enhancements with regexes that have
+  a lot of parens when working on long strings, since you'd not have to  
+  copy them multiple times to the $matches array.
+  
+  Also, it makes $matches much cleaner after a match where you've named the
+  captures you're interested in.
+  
+  (Note that this would not involve the use of PCRE_NO_AUTO_CAPTURE, as
+  that would change the semantics of backreferences)
+
+
diff --git a/ext/pcre/php_pcre.c b/ext/pcre/php_pcre.c
index 557898abf34..6cd6d27a298 100644
--- a/ext/pcre/php_pcre.c
+++ b/ext/pcre/php_pcre.c
@@ -18,13 +18,6 @@
 
 /* $Id$ */
 
-/*
- * TODO
- *
- * - Allow NULL for $matches argument (helps when using preg_match only for
- *   match condition)
- */
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -1622,8 +1615,8 @@ PHP_FUNCTION(preg_grep)
 zend_function_entry pcre_functions[] = {
 	PHP_FE(preg_match,				third_arg_force_ref)
 	PHP_FE(preg_match_all,			third_arg_force_ref)
-	PHP_FE(preg_replace,			NULL)
-	PHP_FE(preg_replace_callback,	NULL)
+	PHP_FE(preg_replace,			fifth_arg_force_ref)
+	PHP_FE(preg_replace_callback,	fifth_arg_force_ref)
 	PHP_FE(preg_split,				NULL)
 	PHP_FE(preg_quote,				NULL)
 	PHP_FE(preg_grep,				NULL)