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Fix GH-23644: crash on a constant-vs-constant empty array comparison #23648

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Fix GH-23644: crash on a constant-vs-constant empty array comparison #23648

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52352a1
Fix GH-23644: crash on a constant-vs-constant empty array comparison
lazerg Sep 10, 2026
d7abcf0
[skip ci] Fix NEWS entry for #23648
lazerg Sep 11, 2026
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2 changes: 2 additions & 0 deletions NEWS
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ PHP NEWS
- Core:
. Fixed incorrect internal pointer and foreach iterator positions when
compacting arrays with holes. (Weilin Du)
. Fixed bug GH-23644 (Optimizer leaves a constant-vs-constant comparison
unfolded, crashing the VM in zval_undefined_cv). (ndossche)

- DOM:
. Fixed use-after-free when re-constructing a DOMXPath whose php:function
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4 changes: 2 additions & 2 deletions Zend/zend_vm_def.h
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Expand Up @@ -10105,7 +10105,7 @@ ZEND_VM_HOT_TYPE_SPEC_HANDLER(ZEND_IS_NOT_EQUAL|ZEND_IS_NOT_IDENTICAL, (op1_info
ZEND_VM_SMART_BRANCH(result, 0);
}

ZEND_VM_TYPE_SPEC_HANDLER(ZEND_IS_IDENTICAL, op->op2_type == IS_CONST && (Z_TYPE_P(RT_CONSTANT(op, op->op2)) == IS_ARRAY && zend_hash_num_elements(Z_ARR_P(RT_CONSTANT(op, op->op2))) == 0), ZEND_IS_IDENTICAL_EMPTY_ARRAY, TMPVARCV, CONST, SPEC(SMART_BRANCH,COMMUTATIVE))
ZEND_VM_TYPE_SPEC_HANDLER(ZEND_IS_IDENTICAL, op->op2_type == IS_CONST && (Z_TYPE_P(RT_CONSTANT(op, op->op2)) == IS_ARRAY && zend_hash_num_elements(Z_ARR_P(RT_CONSTANT(op, op->op2))) == 0), ZEND_IS_IDENTICAL_EMPTY_ARRAY, TMPVARCV, CONST, SPEC(SMART_BRANCH,NO_CONST_CONST,COMMUTATIVE))
{
USE_OPLINE
zval *op1;
Expand All @@ -10118,7 +10118,7 @@ ZEND_VM_TYPE_SPEC_HANDLER(ZEND_IS_IDENTICAL, op->op2_type == IS_CONST && (Z_TYPE
ZEND_VM_SMART_BRANCH(result, 0);
}

ZEND_VM_TYPE_SPEC_HANDLER(ZEND_IS_NOT_IDENTICAL, op->op2_type == IS_CONST && (Z_TYPE_P(RT_CONSTANT(op, op->op2)) == IS_ARRAY && zend_hash_num_elements(Z_ARR_P(RT_CONSTANT(op, op->op2))) == 0), ZEND_IS_NOT_IDENTICAL_EMPTY_ARRAY, TMPVARCV, CONST, SPEC(SMART_BRANCH,COMMUTATIVE))
ZEND_VM_TYPE_SPEC_HANDLER(ZEND_IS_NOT_IDENTICAL, op->op2_type == IS_CONST && (Z_TYPE_P(RT_CONSTANT(op, op->op2)) == IS_ARRAY && zend_hash_num_elements(Z_ARR_P(RT_CONSTANT(op, op->op2))) == 0), ZEND_IS_NOT_IDENTICAL_EMPTY_ARRAY, TMPVARCV, CONST, SPEC(SMART_BRANCH,NO_CONST_CONST,COMMUTATIVE))
{
USE_OPLINE
zval *op1;
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6 changes: 6 additions & 0 deletions Zend/zend_vm_execute.h
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26 changes: 26 additions & 0 deletions ext/opcache/tests/opt/gh23644.phpt
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@@ -0,0 +1,26 @@
--TEST--
GH-23644: Crash on a constant-vs-constant empty array comparison
--INI--
opcache.enable=1
opcache.enable_cli=1
opcache.optimization_level=-1
--EXTENSIONS--
opcache
--FILE--
<?php
function f($x) {
if (null !== $x || [] !== $x) { return 1; }
return 2;
}

function g($x) {
if ($x === null) { return $x === [] ? 'eq' : 'ne'; }
return 'other';
}

var_dump(f(null));
var_dump(g(null));
?>
--EXPECT--
int(1)
string(2) "ne"