diff --git a/main/main.c b/main/main.c
index 2d58b9c99ce86..adaef5c85b50e 100644
--- a/main/main.c
+++ b/main/main.c
@@ -2142,6 +2142,13 @@ int php_module_startup(sapi_module_struct *sf, zend_module_entry *additional_mod
 		REGISTER_MAIN_STRINGL_CONSTANT("PHP_BINARY", "", 0, CONST_PERSISTENT | CONST_CS);
 	}
 
+	/* Standard three-way comparison/ordering enumeration
+	 * Matches <=>
+	 */
+	REGISTER_MAIN_LONG_CONSTANT("CMP_LT", -1, CONST_PERSISTENT | CONST_CS);
+	REGISTER_MAIN_LONG_CONSTANT("CMP_EQ", 0, CONST_PERSISTENT | CONST_CS);
+	REGISTER_MAIN_LONG_CONSTANT("CMP_GT", 1, CONST_PERSISTENT | CONST_CS);
+
 	php_output_register_constants();
 	php_rfc1867_register_constants();
 
diff --git a/tests/lang/constants/CMP.phpt b/tests/lang/constants/CMP.phpt
new file mode 100644
index 0000000000000..56de486b33856
--- /dev/null
+++ b/tests/lang/constants/CMP.phpt
@@ -0,0 +1,32 @@
+--TEST--
+CMP_LT, CMP_EQ and CMP_GT ordering constants
+--FILE--
+<?php
+
+echo "Check values", PHP_EOL;
+var_dump(CMP_LT, CMP_EQ, CMP_GT);
+
+echo "Make sure they match <=> return values", PHP_EOL;
+var_dump((1 <=> 2) === CMP_LT);
+var_dump((1 <=> 1) === CMP_EQ);
+var_dump((2 <=> 1) === CMP_GT);
+
+echo "Make sure they're case-sensitive and lowercase variants aren't defined", PHP_EOL;
+var_dump(defined("cmp_lt"));
+var_dump(defined("cmp_eq"));
+var_dump(defined("cmp_gt"));
+
+?>
+--EXPECTF--
+Check values
+int(-1)
+int(0)
+int(1)
+Make sure they match <=> return values
+bool(true)
+bool(true)
+bool(true)
+Make sure they're case-sensitive and lowercase variants aren't defined
+bool(false)
+bool(false)
+bool(false)