diff --git a/Zend/Optimizer/zend_optimizer.c b/Zend/Optimizer/zend_optimizer.c
index 603e9e8d399..0f1453cfdb4 100644
--- a/Zend/Optimizer/zend_optimizer.c
+++ b/Zend/Optimizer/zend_optimizer.c
@@ -539,17 +539,6 @@ bool zend_optimizer_replace_by_const(zend_op_array *op_array,
 		if (opline->op1_type == type &&
 			opline->op1.var == var) {
 			switch (opline->opcode) {
-				case ZEND_SEND_VAR_EX:
-				case ZEND_SEND_FUNC_ARG:
-					opline->extended_value = 0;
-					opline->opcode = ZEND_SEND_VAL_EX;
-					break;
-				case ZEND_SEND_VAR_NO_REF_EX:
-					opline->opcode = ZEND_SEND_VAL;
-					break;
-				case ZEND_SEND_USER:
-					opline->opcode = ZEND_SEND_VAL_EX;
-					break;
 				/* In most cases IS_TMP_VAR operand may be used only once.
 				 * The operands are usually destroyed by the opcode handler.
 				 * However, there are some exception which keep the operand alive. In that case
diff --git a/Zend/tests/by_ref_optimization.phpt b/Zend/tests/by_ref_optimization.phpt
new file mode 100644
index 00000000000..02431b6cbea
--- /dev/null
+++ b/Zend/tests/by_ref_optimization.phpt
@@ -0,0 +1,19 @@
+--TEST--
+Don't optimize send opcodes that differ in by-ref behavior
+--FILE--
+<?php
+
+call_user_func('ref', function_exists('strlen'));
+ref(function_exists('strlen'));
+
+function ref(&$x) {
+    var_dump($x);
+}
+
+?>
+--EXPECTF--
+Warning: ref(): Argument #1 ($x) must be passed by reference, value given in %s on line %d
+bool(true)
+
+Notice: Only variables should be passed by reference in %s on line %d
+bool(true)