diff --git a/Zend/tests/gh23662.phpt b/Zend/tests/gh23662.phpt
new file mode 100644
index 000000000000..426b6e2aa5d7
--- /dev/null
+++ b/Zend/tests/gh23662.phpt
@@ -0,0 +1,12 @@
+--TEST--
+GH-23662 (print_r() results in warning for NAN)
+--FILE--
+<?php
+print_r(NAN);
+print_r([NAN]);
+?>
+--EXPECT--
+NANArray
+(
+    [0] => NAN
+)
diff --git a/Zend/zend.c b/Zend/zend.c
index 42e6fb568a22..3cfc0ffd2512 100644
--- a/Zend/zend.c
+++ b/Zend/zend.c
@@ -602,6 +602,9 @@ static void zend_print_zval_r_to_buf(smart_str *buf, zval *expr, int indent) /*
 		case IS_LONG:
 			smart_str_append_long(buf, Z_LVAL_P(expr));
 			break;
+		case IS_DOUBLE:
+			smart_str_append_double(buf, Z_DVAL_P(expr), EG(precision), false);
+			break;
 		case IS_REFERENCE:
 			zend_print_zval_r_to_buf(buf, Z_REFVAL_P(expr), indent);
 			break;