diff --git a/UPGRADING b/UPGRADING
index 78956ae29a6fb..0ce30cf66fd6b 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -210,6 +210,10 @@ PHP 8.4 UPGRADE NOTES
     As a consequence, LoongArch JIT support has been added, spaces
     are now allowed between braces in Perl-compatible items, and
     variable-length lookbehind assertions are now supported.
+  . Added support for the "r" (PCRE2_EXTRA_CASELESS_RESTRICT) modifier, as well
+    as the (?r) mode modifier. When enabled along with the case-insensitive
+    modifier ("i"), the expression locks out mixing of ASCII and non-ASCII
+    characters.
 
 - PDO:
   . Added support for driver-specific subclasses.
diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index 217d86809ad46..0489224bc5a90 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -185,6 +185,9 @@ PHP 8.4 INTERNALS UPGRADE NOTES
      When flags should be ignored, pass 0 to the flags argument.
    - php_pcre_match_impl() and pcre_get_compiled_regex_cache_ex() now use
      proper boolean argument types instead of integer types.
+   - pcre_get_compiled_regex_cache_ex() now provides an option to collect extra
+     options (from modifiers used in the expression, for example), and calls
+     pcre2_set_compile_extra_options() with those options.
 
 ========================
 4. OpCode changes
diff --git a/ext/pcre/php_pcre.c b/ext/pcre/php_pcre.c
index c14cc524c5b3a..49526330cff1a 100644
--- a/ext/pcre/php_pcre.c
+++ b/ext/pcre/php_pcre.c
@@ -592,6 +592,7 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache_ex(zend_string *regex, bo
 #else
 	uint32_t			 coptions = 0;
 #endif
+	uint32_t			 eoptions = PHP_PCRE_DEFAULT_EXTRA_COPTIONS;
 	PCRE2_UCHAR	         error[128];
 	PCRE2_SIZE           erroffset;
 	int                  errnumber;
@@ -722,6 +723,7 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache_ex(zend_string *regex, bo
 			/* PCRE specific options */
 			case 'A':	coptions |= PCRE2_ANCHORED;		break;
 			case 'D':	coptions |= PCRE2_DOLLAR_ENDONLY;break;
+			case 'r':	eoptions |= PCRE2_EXTRA_CASELESS_RESTRICT; break;
 			case 'S':	/* Pass. */					break;
 			case 'X':	/* Pass. */					break;
 			case 'U':	coptions |= PCRE2_UNGREEDY;		break;
@@ -776,6 +778,8 @@ PHPAPI pcre_cache_entry* pcre_get_compiled_regex_cache_ex(zend_string *regex, bo
 	}
 	pcre2_set_character_tables(cctx, tables);
 
+	pcre2_set_compile_extra_options(cctx, eoptions);
+
 	/* Compile pattern and display a warning if compilation failed. */
 	re = pcre2_compile((PCRE2_SPTR)pattern, pattern_len, coptions, &errnumber, &erroffset, cctx);
 
diff --git a/ext/pcre/tests/preg_match_caseless_restrict.phpt b/ext/pcre/tests/preg_match_caseless_restrict.phpt
new file mode 100644
index 0000000000000..8238e286b1cf1
--- /dev/null
+++ b/ext/pcre/tests/preg_match_caseless_restrict.phpt
@@ -0,0 +1,101 @@
+--TEST--
+testing /r modifier in preg_* functions
+--FILE--
+<?php
+echo "SK substitute matching" . PHP_EOL;
+var_dump(preg_match('/AskZ/iur', 'AskZ')); // match
+var_dump(preg_match('/AskZ/iur', 'aSKz')); // match
+var_dump(preg_match('/AskZ/iur', "A\u{17f}kZ")); // no match
+var_dump(preg_match('/AskZ/iur', "As\u{212a}Z")); // no match
+var_dump(preg_match('/AskZ/iu', 'AskZ')); // match
+var_dump(preg_match('/AskZ/iu', 'aSKz')); // match
+var_dump(preg_match('/AskZ/iu', "A\u{17f}kZ")); // match
+var_dump(preg_match('/AskZ/iu', "As\u{212a}Z")); // match
+
+echo "K substitute matching" . PHP_EOL;
+var_dump(preg_match('/k/iu', "\u{212A}"));
+var_dump(preg_match('/k/iur', "\u{212A}"));
+
+echo "non-ASCII in expressions" . PHP_EOL;
+var_dump(preg_match('/A\x{17f}\x{212a}Z/iu', 'AskZ')); // match
+var_dump(preg_match('/A\x{17f}\x{212a}Z/iur', 'AskZ')); // no match
+
+echo "Character sets" . PHP_EOL;
+var_dump(preg_match('/[AskZ]+/iur', 'AskZ')); // match
+var_dump(preg_match('/[AskZ]+/iur', 'aSKz')); // match
+var_dump(preg_match('/[AskZ]+/iur', "A\u{17f}kZ")); // match
+var_dump(preg_match('/[AskZ]+/iur', "As\u{212a}Z")); // match
+var_dump(preg_match('/[AskZ]+/iu', 'AskZ')); // match
+var_dump(preg_match('/[AskZ]+/iu', 'aSKz')); // match
+var_dump(preg_match('/[AskZ]+/iu', "A\u{17f}kZ")); // match
+var_dump(preg_match('/[AskZ]+/iu', "As\u{212a}Z")); // match
+
+echo "non-ASCII in character sets" . PHP_EOL;
+var_dump(preg_match('/[\x{17f}\x{212a}]+/iur', 'AskZ')); // no match
+var_dump(preg_match('/[\x{17f}\x{212a}]+/iu', 'AskZ')); // match
+
+echo "Meta characters and negate character sets". PHP_EOL;
+var_dump(preg_match('/[^s]+/iur', "A\u{17f}Z")); // match
+var_dump(preg_match('/[^s]+/iu', "A\u{17f}Z")); // match
+var_dump(preg_match('/[^s]+/iu', "A\u{17f}Z")); // match
+var_dump(preg_match('/[^k]+/iur', "A\u{212a}Z")); // match
+var_dump(preg_match('/[^k]+/iu', "A\u{212a}Z")); // match
+var_dump(preg_match('/[^sk]+/iur', "A\u{17f}\u{212a}Z")); // match
+var_dump(preg_match('/[^sk]+/iu', "A\u{17f}\u{212a}Z")); // match
+var_dump(preg_match('/[^\x{17f}]+/iur', "AsSZ")); // match
+var_dump(preg_match('/[^\x{17f}]+/iu', "AsSZ")); // match
+
+echo "Modifier used within the expression" . PHP_EOL;
+var_dump(preg_match('/s(?r)s(?-r)s(?r:s)s/iu', "\u{17f}S\u{17f}S\u{17f}")); // match
+var_dump(preg_match('/s(?r)s(?-r)s(?r:s)s/iu', "\u{17f}\u{17f}\u{17f}S\u{17f}")); // no match
+var_dump(preg_match('/s(?r)s(?-r)s(?r:s)s/iu', "\u{17f}S\u{17f}\u{17f}\u{17f}")); // no match
+var_dump(preg_match('/k(?^i)k/iur', "K\u{212a}")); // match
+var_dump(preg_match('/k(?^i)k/iur', "\u{212a}\u{212a}")); // no match
+
+echo "Done";
+?>
+--EXPECT--
+SK substitute matching
+int(1)
+int(1)
+int(0)
+int(0)
+int(1)
+int(1)
+int(1)
+int(1)
+K substitute matching
+int(1)
+int(0)
+non-ASCII in expressions
+int(1)
+int(0)
+Character sets
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+non-ASCII in character sets
+int(0)
+int(1)
+Meta characters and negate character sets
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+int(1)
+Modifier used within the expression
+int(1)
+int(0)
+int(0)
+int(1)
+int(0)
+Done