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Merged
iluuu1994 merged 2 commits into from
Jan 31, 2026
Merged

VAR|TMP overhaul #20628

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7f5e296
VAR|TMP overhaul
iluuu1994 Nov 27, 2025
824a4ab
Add back support for Zend/tests/list/bug73663.phpt
iluuu1994 Jan 31, 2026
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4 changes: 4 additions & 0 deletions UPGRADING.INTERNALS
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Expand Up@@ -56,6 +56,10 @@ PHP 8.6 INTERNALS UPGRADE NOTES
node.
. The zend_exception_save() and zend_exception_restore() functions were
removed.
. Internal functions that return by reference are now expected to
automatically unwrap references when the result of the call is stored in an
IS_TMP_VAR variable. This may be achieved by calling the
zend_return_unwrap_ref() function.

========================
2. Build system changes
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35 changes: 21 additions & 14 deletions Zend/Optimizer/block_pass.c
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Expand Up@@ -289,29 +289,34 @@ static void zend_optimize_block(zend_basic_block *block, zend_op_array *op_array
MAKE_NOP(opline);
++(*opt_count);
break;
case ZEND_ASSIGN:
case ZEND_ASSIGN_DIM:
case ZEND_ASSIGN_OBJ:
case ZEND_ASSIGN_STATIC_PROP:
case ZEND_ASSIGN_OP:
case ZEND_ASSIGN_DIM_OP:
case ZEND_ASSIGN_OBJ_OP:
case ZEND_ASSIGN_STATIC_PROP_OP:
case ZEND_PRE_INC:
case ZEND_PRE_DEC:
case ZEND_PRE_INC_OBJ:
case ZEND_PRE_DEC_OBJ:
case ZEND_PRE_INC_STATIC_PROP:
case ZEND_PRE_DEC_STATIC_PROP:
case ZEND_QM_ASSIGN:
if (src < op_array->opcodes + block->start) {
break;
}
src->result_type = IS_UNUSED;
VAR_SOURCE(opline->op1) = NULL;
MAKE_NOP(opline);
++(*opt_count);
if (src->op1_type & (IS_VAR|IS_TMP_VAR)) {
src->opcode = ZEND_FREE;

@dstogovdstogovDec 8, 2025

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Replacing QM_ASSIGN with FREE opens possibility to deeper application of the same optimization.

} else if (src->op1_type == IS_CONST) {
MAKE_NOP(src);
} else if (src->op1_type == IS_CV) {
src->opcode = ZEND_CHECK_VAR;
SET_UNUSED(src->result);
}
break;
default:
if (!zend_op_may_elide_result(src->opcode)) {
break;
}
if (src < op_array->opcodes + block->start) {
break;
}
src->result_type = IS_UNUSED;
VAR_SOURCE(opline->op1) = NULL;
MAKE_NOP(opline);
++(*opt_count);
break;
}
}
Expand DownExpand Up@@ -985,6 +990,8 @@ static void zend_optimize_block(zend_basic_block *block, zend_op_array *op_array
src = VAR_SOURCE(opline->op1);
if (src &&
src->opcode != ZEND_COPY_TMP &&
/* See gh20628_borked_live_range_calc.phpt. */
src->opcode != ZEND_NEW &&
src->opcode != ZEND_ADD_ARRAY_ELEMENT &&
src->opcode != ZEND_ADD_ARRAY_UNPACK &&
(src->opcode != ZEND_DECLARE_LAMBDA_FUNCTION ||
Expand Down
8 changes: 7 additions & 1 deletion Zend/Optimizer/dce.c
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Expand Up@@ -162,10 +162,16 @@ static inline bool may_have_side_effects(
case ZEND_EXT_FCALL_END:
case ZEND_TICKS:
case ZEND_YIELD:
case ZEND_YIELD_FROM:
case ZEND_VERIFY_NEVER_TYPE:
/* Intrinsic side effects */
return true;
case ZEND_YIELD_FROM: {
uint32_t t1 = OP1_INFO();
if ((t1 & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY && MAY_BE_EMPTY_ONLY(t1)) {
return false;
}
return true;
}
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case ZEND_DO_FCALL:
case ZEND_DO_FCALL_BY_NAME:
case ZEND_DO_ICALL:
Expand Down
7 changes: 7 additions & 0 deletions Zend/Optimizer/zend_inference.c
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Expand Up@@ -5336,6 +5336,13 @@ ZEND_API bool zend_may_throw_ex(const zend_op *opline, const zend_ssa_op *ssa_op
return 1;
}
return 0;
case ZEND_YIELD_FROM: {
uint32_t t1 = OP1_INFO();
if ((t1 & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_ARRAY && MAY_BE_EMPTY_ONLY(t1)) {
return false;
}
return true;

@iluuu1994iluuu1994Dec 4, 2025

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YIELD_FROM from generators can throw if the generator is closed, even for empty arrays. So this optimization may be unsound.

@bwoebibwoebiDec 5, 2025

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I would not mind doing the inverse - changing YIELD_FROM to not throw on empty array, though...

@dstogovdstogovDec 8, 2025

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Taking into account the "closed" generator, this is wrong.

}
default:
return 1;
}
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12 changes: 12 additions & 0 deletions Zend/tests/gh20628_001.phpt
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@@ -0,0 +1,12 @@
--TEST--
Nullsafe operator does not support BP_VAR_W
--FILE--
<?php

function &test($foo) {
return $foo?->bar();
}

?>
--EXPECTF--
Fatal error: Cannot take reference of a nullsafe chain in %s on line %d
22 changes: 22 additions & 0 deletions Zend/tests/gh20628_002.phpt
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@@ -0,0 +1,22 @@
--TEST--
Pipes support return-by-reference
--FILE--
<?php

function &foo($val) {
global $x;
$x = $val;
return $x;
}

function &bar() {
return 42 |> foo(...);
}

$xRef = &bar();
$xRef++;
var_dump($x);

?>
--EXPECT--
int(43)
71 changes: 71 additions & 0 deletions Zend/tests/gh20628_003.phpt
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@@ -0,0 +1,71 @@
--TEST--
Missing separation for ASSIGN_DIM with ref OP_DATA
--FILE--
<?php

function a() {
$a[] = $b[] = &$a;
var_dump($a, $b);
}

function b() {
$a = [];
$b = [];
$a[] = $b[] = &$a;
var_dump($a, $b);
}

function c() {
$a[] = $b = &$a;
var_dump($a, $b);
}

function d() {
$a = $b[] = &$a;
var_dump($a, $b);
}

a();
b();
c();
d();

?>
--EXPECT--
array(1) {
[0]=>
NULL
}
array(1) {
[0]=>
&array(1) {
[0]=>
NULL
}
}
array(1) {
[0]=>
array(0) {
}
}
array(1) {
[0]=>
&array(1) {
[0]=>
array(0) {
}
}
}
array(1) {
[0]=>
NULL
}
array(1) {
[0]=>
NULL
}
NULL
array(1) {
[0]=>
&NULL
}
3 changes: 3 additions & 0 deletions Zend/tests/gh20628_004.inc
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@@ -0,0 +1,3 @@
<?php

$this->bar();
22 changes: 22 additions & 0 deletions Zend/tests/gh20628_004.phpt
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@@ -0,0 +1,22 @@
--TEST--
Invalid opcode for method call with FETCH_THIS
--FILE--
<?php

class Foo {
public function bar() {
var_dump($this, __METHOD__);
}

public function test() {
require __DIR__ . '/gh20628_004.inc';
}
}

(new Foo)->test();

?>
--EXPECTF--
object(Foo)#%d (0) {
}
string(8) "Foo::bar"
8 changes: 4 additions & 4 deletions Zend/tests/operator_unsupported_types.phpt
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Expand Up@@ -287,7 +287,7 @@ Unsupported operand types: stdClass * stdClass
Unsupported operand types: stdClass * resource
Unsupported operand types: stdClass * string
Unsupported operand types: resource * array
Unsupported operand types: stdClass * resource
Unsupported operand types: resource * stdClass
Unsupported operand types: resource * resource
Unsupported operand types: resource * string
Unsupported operand types: string * array
Expand DownExpand Up@@ -753,7 +753,7 @@ Unsupported operand types: stdClass & stdClass
Unsupported operand types: stdClass & resource
Unsupported operand types: stdClass & string
Unsupported operand types: resource & array
Unsupported operand types: stdClass & resource
Unsupported operand types: resource & stdClass
Unsupported operand types: resource & resource
Unsupported operand types: resource & string
Unsupported operand types: string & array
Expand DownExpand Up@@ -828,7 +828,7 @@ Unsupported operand types: stdClass | stdClass
Unsupported operand types: stdClass | resource
Unsupported operand types: stdClass | string
Unsupported operand types: resource | array
Unsupported operand types: stdClass | resource
Unsupported operand types: resource | stdClass
Unsupported operand types: resource | resource
Unsupported operand types: resource | string
Unsupported operand types: string | array
Expand DownExpand Up@@ -903,7 +903,7 @@ Unsupported operand types: stdClass ^ stdClass
Unsupported operand types: stdClass ^ resource
Unsupported operand types: stdClass ^ string
Unsupported operand types: resource ^ array
Unsupported operand types: stdClass ^ resource
Unsupported operand types: resource ^ stdClass
Unsupported operand types: resource ^ resource
Unsupported operand types: resource ^ string
Unsupported operand types: string ^ array
Expand Down
2 changes: 1 addition & 1 deletion Zend/tests/stack_limit/stack_limit_015.phpt
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Expand Up@@ -9,7 +9,7 @@ if (!function_exists('zend_test_zend_call_stack_get')) die("skip zend_test_zend_
--EXTENSIONS--
zend_test
--INI--
zend.max_allowed_stack_size=128K
zend.max_allowed_stack_size=64K
--FILE--
<?php

Expand Down
2 changes: 1 addition & 1 deletion Zend/zend_closures.c
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Expand Up@@ -339,7 +339,7 @@ static ZEND_NAMED_FUNCTION(zend_closure_call_magic) /* {{{ */ {
fcc.called_scope = zend_get_called_scope(EG(current_execute_data));

zend_call_function(&fci, &fcc);

zend_return_unwrap_ref(EG(current_execute_data), return_value);
zval_ptr_dtor(&fci.params[1]);
}
/* }}} */
Expand Down
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