From: Nikita Popov <nikita.ppv@gmail.com>
Date: Sat, 17 Feb 2018 11:41:57 +0000 (+0100)
Subject: Fix COALESCE jump optimization
X-Git-Tag: php-7.3.0alpha1~391
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=257f07ef6d650936469dfed292a852f568e562b4;p=php

Fix COALESCE jump optimization
---

diff --git a/ext/opcache/Optimizer/dfa_pass.c b/ext/opcache/Optimizer/dfa_pass.c
index 4a7ba6ba69..9e16a9c55c 100644
--- a/ext/opcache/Optimizer/dfa_pass.c
+++ b/ext/opcache/Optimizer/dfa_pass.c
@@ -819,14 +819,12 @@ optimize_jmpnz:
 						} else {
 							zend_ssa_var *var = &ssa->vars[ssa_op->result_def];
 							if (var->use_chain < 0 && var->phi_use_chain == NULL) {
-								ssa_op->result_def = -1;
 								if (opline->result_type & (IS_TMP_VAR|IS_VAR)) {
 									zend_optimizer_remove_live_range_ex(op_array, opline->result.var, var->definition);
 								}
-								zend_ssa_unlink_use_chain(ssa, opline - op_array->opcodes, ssa_op->op1_use);
-								ssa_op->op1_use = -1;
-								ssa_op->op1_use_chain = -1;
 								opline->opcode = ZEND_JMP;
+								opline->result_type = IS_UNUSED;
+								zend_ssa_remove_result_def(ssa, ssa_op);
 								COPY_NODE(opline->op1, opline->op2);
 								take_successor_0(ssa, block_num, block);
 								goto optimize_jmp;
diff --git a/ext/opcache/tests/jmp_elim_004.phpt b/ext/opcache/tests/jmp_elim_004.phpt
new file mode 100644
index 0000000000..e31af3da17
--- /dev/null
+++ b/ext/opcache/tests/jmp_elim_004.phpt
@@ -0,0 +1,17 @@
+--TEST--
+Incorrect empty basic block elimination
+--INI--
+opcache.enable_cli=1
+opcache.optimization_level=-1
+--FILE--
+<?php
+
+function test() {
+    $foo = "test";
+    var_dump($foo ?? "default");
+}
+test();
+
+?>
+--EXPECT--
+string(4) "test"