From: Nikita Popov <nikita.ppv@gmail.com>
Date: Mon, 17 Apr 2017 10:17:32 +0000 (+0200)
Subject: Fix loop identification
X-Git-Tag: php-7.1.5RC1~19^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=abf16c18c77815b310af9528106d0c76eb8a81ab;p=php

Fix loop identification

When assigning loop headers, we should treat already detected
loops as collapsed to their loop header, instead of ignoring them.

This fixes the loop header of BB2 in mandel2 if live-range CFG
splitting is enabled.
---

diff --git a/ext/opcache/Optimizer/zend_cfg.c b/ext/opcache/Optimizer/zend_cfg.c
index 1e9bfe47bc..ec7116691e 100644
--- a/ext/opcache/Optimizer/zend_cfg.c
+++ b/ext/opcache/Optimizer/zend_cfg.c
@@ -855,7 +855,10 @@ int zend_cfg_identify_loops(const zend_op_array *op_array, zend_cfg *cfg, uint32
 		}
 		while (zend_worklist_len(&work)) {
 			j = zend_worklist_pop(&work);
-			if (blocks[j].loop_header < 0 && j != i) {
+			while (blocks[j].loop_header >= 0) {
+				j = blocks[j].loop_header;
+			}
+			if (j != i) {
 				blocks[j].loop_header = i;
 				for (k = 0; k < blocks[j].predecessors_count; k++) {
 					zend_worklist_push(&work, cfg->predecessors[blocks[j].predecessor_offset + k]);