diff --git a/Zend/tests/int_special_values.phpt b/Zend/tests/int_special_values.phpt
new file mode 100644
index 00000000000..e1a50b6ecba
--- /dev/null
+++ b/Zend/tests/int_special_values.phpt
@@ -0,0 +1,37 @@
+--TEST--
+Conversion of special float values to int
+--FILE--
+<?php
+$values = [
+    0.0,
+    INF,
+    -INF,
+    1 / INF,
+    -1 / INF, // Negative zero,
+    NAN
+];
+
+foreach($values as $value) {
+    var_dump($value);
+    var_dump((int)$value);
+    echo PHP_EOL;
+}
+?>
+--EXPECT--
+float(0)
+int(0)
+
+float(INF)
+int(0)
+
+float(-INF)
+int(0)
+
+float(0)
+int(0)
+
+float(-0)
+int(0)
+
+float(NAN)
+int(0)
\ No newline at end of file
diff --git a/Zend/zend_operators.h b/Zend/zend_operators.h
index 1ab9518b9ad..edc2d56e5b8 100644
--- a/Zend/zend_operators.h
+++ b/Zend/zend_operators.h
@@ -71,8 +71,21 @@ ZEND_API zend_bool instanceof_function_ex(const zend_class_entry *instance_ce, c
 ZEND_API zend_bool instanceof_function(const zend_class_entry *instance_ce, const zend_class_entry *ce TSRMLS_DC);
 END_EXTERN_C()
 
+/* isnan() might not be available (<C99), so we'll define it if so */
+#ifndef isnan
+	/* NaN is never equal to itself */
+#	define isnan(n) ((n) != (n))
+#endif
+
 #if ZEND_DVAL_TO_LVAL_CAST_OK
-# define zend_dval_to_lval(d) ((long) (d))
+static zend_always_inline long zend_dval_to_lval(double d)
+{
+    if (EXPECTED(!isnan(d))) {
+        return (long)d;
+    } else {
+        return 0;
+    }
+}
 #elif SIZEOF_LONG == 4
 static zend_always_inline long zend_dval_to_lval(double d)
 {
@@ -87,6 +100,8 @@ static zend_always_inline long zend_dval_to_lval(double d)
 			dmod = ceil(dmod) + two_pow_32;
 		}
 		return (long)(unsigned long)dmod;
+	} else if (UNEXPECTED(isnan(d))) {
+		return 0;
 	}
 	return (long)d;
 }
@@ -105,6 +120,8 @@ static zend_always_inline long zend_dval_to_lval(double d)
 			dmod += two_pow_64;
 		}
 		return (long)(unsigned long)dmod;
+	} else if (UNEXPECTED(isnan(d))) {
+		return 0;
 	}
 	return (long)d;
 }