From: Nikita Popov <nikic@php.net>
Date: Fri, 30 Dec 2016 21:23:12 +0000 (+0100)
Subject: Compact literals: Deduplicate empty array literals
X-Git-Tag: php-7.2.0alpha1~563
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=18904aa3e2fa73a43c5b1b552134cf38a0302f7c;p=php

Compact literals: Deduplicate empty array literals
---

diff --git a/ext/opcache/Optimizer/compact_literals.c b/ext/opcache/Optimizer/compact_literals.c
index 6d549220ab..e557f02a11 100644
--- a/ext/opcache/Optimizer/compact_literals.c
+++ b/ext/opcache/Optimizer/compact_literals.c
@@ -123,6 +123,7 @@ void zend_optimizer_compact_literals(zend_op_array *op_array, zend_optimizer_ctx
 	int l_null = -1;
 	int l_false = -1;
 	int l_true = -1;
+	int l_empty_arr = -1;
 	HashTable hash;
 	zend_string *key = NULL;
 	void *checkpoint = zend_arena_checkpoint(ctx->arena);
@@ -481,6 +482,22 @@ void zend_optimizer_compact_literals(zend_op_array *op_array, zend_optimizer_ctx
 						}
 					}
 					break;
+				case IS_ARRAY:
+					if (zend_hash_num_elements(Z_ARRVAL(op_array->literals[i])) == 0) {
+						if (l_empty_arr < 0) {
+							l_empty_arr = j;
+							if (i != j) {
+								op_array->literals[j] = op_array->literals[i];
+								info[j] = info[i];
+							}
+							j++;
+						} else {
+							zval_dtor(&op_array->literals[i]);
+						}
+						map[i] = l_empty_arr;
+						break;
+					}
+					/* break missing intentionally */
 				default:
 					/* don't merge other types */
 					map[i] = j;