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Fix COPY_TMP live range construction with optimization

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The use may be optimized away, leaving us only with the free use.
Also fix off-by-one error in the other optimization case.
This commit is contained in:
Nikita Popov 2021-11-11 10:21:39 +01:00
parent 64915775a7
commit 8c4a7f20f5
2 changed files with 11 additions and 0 deletions
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4
Zend/tests/coalesce_assign_optimization.phpt
View file

@ -6,9 +6,13 @@ function test() {
$a[X] ??= Y;
var_dump($a);
}
function test2(string $b, int $c) {
$a[~$b] ??= $c;
}
define('X', 1);
define('Y', 2);
test();
test2("", 0);
?>
--EXPECT--
array(1) {

7
Zend/zend_opcode.c
View file

@ -729,6 +729,7 @@ static void emit_live_range(
if (use_opline->opcode != ZEND_FREE) {
/* This can happen if one branch of the coalesce has been optimized away.
* In this case we should emit a normal live-range instead. */
start++;
break;
}
@ -744,6 +745,12 @@ static void emit_live_range(
do {
use_opline--;
/* The use might have been optimized away, in which case we will hit the def
* instead. */
if (use_opline->opcode == ZEND_COPY_TMP && use_opline->result.var == rt_var_num) {
return;
}
} while (!(
((use_opline->op1_type & (IS_TMP_VAR|IS_VAR)) && use_opline->op1.var == rt_var_num) ||
((use_opline->op2_type & (IS_TMP_VAR|IS_VAR)) && use_opline->op2.var == rt_var_num)