From: Dmitry Stogov <dmitry@zend.com>
Date: Wed, 9 Oct 2019 06:08:25 +0000 (+0300)
Subject: Otimize out useless QM_ASSIGN
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=170ed1f5a7b2f2f052445761080c96a3a3cfa884;p=php

Otimize out useless QM_ASSIGN
---

diff --git a/ext/opcache/Optimizer/block_pass.c b/ext/opcache/Optimizer/block_pass.c
index 6ca3d02468..4e4d270b62 100644
--- a/ext/opcache/Optimizer/block_pass.c
+++ b/ext/opcache/Optimizer/block_pass.c
@@ -883,6 +883,18 @@ optimize_const_unary_op:
 					/* strip T = QM_ASSIGN(T) */
 					MAKE_NOP(opline);
 					++(*opt_count);
+				} else if (opline->op1_type == IS_TMP_VAR &&
+				           opline->result_type == IS_TMP_VAR &&
+				           !zend_bitset_in(used_ext, VAR_NUM(opline->op1.var))) {
+					/* T1 = ..., T2 = QM_ASSIGN(T1) to T2 = ..., NOP */
+					src = VAR_SOURCE(opline->op1);
+					if (src) {
+						src->result.var = opline->result.var;
+						VAR_SOURCE(opline->op1) = NULL;
+						VAR_SOURCE(opline->result) = src;
+						MAKE_NOP(opline);
+						++(*opt_count);
+					}
 				}
 				break;
 		}