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Fix GH-22763: Clear ZREG_TYPE_ONLY flag for in-register vars in zend_jit_snapshot_handler() #22764

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Fix GH-22763: Clear ZREG_TYPE_ONLY flag for in-register vars in zend_jit_snapshot_handler() #22764

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4 changes: 3 additions & 1 deletion ext/opcache/jit/zend_jit_ir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -859,12 +859,14 @@ void *zend_jit_snapshot_handler(ir_ctx *ctx, ir_ref snapshot_ref, ir_insn *snaps
t->stack_map[t->exit_info[exit_point].stack_offset + var].flags = ZREG_TYPE_ONLY;
} else {
if ((exit_flags & ZEND_JIT_EXIT_FIXED)
&& t->stack_map[t->exit_info[exit_point].stack_offset + var].reg != IR_REG_NUM(reg)) {
&& (t->stack_map[t->exit_info[exit_point].stack_offset + var].reg != IR_REG_NUM(reg)
|| (t->stack_map[t->exit_info[exit_point].stack_offset + var].flags & ~(ZREG_LOAD|ZREG_STORE|ZREG_LAST_USE)))) {
exit_point = zend_jit_duplicate_exit_point(ctx, t, exit_point, snapshot_ref);
addr = (void*)zend_jit_trace_get_exit_addr(exit_point);
exit_flags &= ~ZEND_JIT_EXIT_FIXED;
}
t->stack_map[t->exit_info[exit_point].stack_offset + var].reg = IR_REG_NUM(reg);
t->stack_map[t->exit_info[exit_point].stack_offset + var].flags &= (ZREG_LOAD|ZREG_STORE|ZREG_LAST_USE);
}
} else {
if ((exit_flags & ZEND_JIT_EXIT_FIXED)
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2 changes: 2 additions & 0 deletions ext/opcache/jit/zend_jit_trace.c
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Expand Up @@ -3558,6 +3558,8 @@ static int zend_jit_trace_deoptimization(
}
}
} else if (STACK_FLAGS(parent_stack, i) == ZREG_TYPE_ONLY) {
ZEND_ASSERT(reg == ZREG_NONE);

uint8_t type = STACK_TYPE(parent_stack, i);

if (!zend_jit_store_type(jit, i, type)) {
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58 changes: 58 additions & 0 deletions ext/opcache/tests/jit/gh22763.phpt
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@@ -0,0 +1,58 @@
--TEST--
GH-22763: JIT fails to clear ZREG_TYPE_ONLY after setting reg
--FILE--

@iliaal iliaal Jul 21, 2026

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nit: with no --INI-- this runs at the default opcache.jit_hot_loop=61, so no trace compiles for findMiddleSnake (3-iteration loop, called once) and the assert never fires. It passes unpatched here. --EXTENSIONS-- opcache + --INI-- with jit_hot_loop=1 (like the other jit/ tests) makes it actually reproduce.

@arnaud-lb arnaud-lb Jul 21, 2026

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run-tests.php sets a number of JIT settings including opcache.jit_hot_loop=1: https://github.com/arnaud-lb/php-src/blob/d341eb74fbc3fbc48fafae47b6d9b0f1158b551c/run-tests.php#L295

It reproduces with make test TESTS="ext/opcache/tests/jit/gh22763.phpt -d opcache.jit=tracing".

CI runs tests with an without -d opcache.jit=tracing

@iliaal iliaal Jul 21, 2026

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Hmm interesting, locally I had to make tweaks to trigger initial error.

@iliaal iliaal Jul 21, 2026

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Actually that's a user error, I ran test manually via php -d all good then.

<?php

function findMiddleSnake(array $a, int $aLo, int $aHi, array $b, int $bLo, int $bHi): array
{
$n = $aHi - $aLo;
$m = $bHi - $bLo;
$delta = $n - $m;
$deltaIsOdd = ($delta & 1) !== 0;
$offset = 4;
$size = 2 * 3 + 2;
$vf = array_fill(0, $size, 0);
$vb = array_fill(0, $size, 0);

$d = 2;
$x = 0;

for ($k = -$d; $k <= $d; $k += 2) {
if ($k === -$d || ($k !== $d && $vb[$offset + $k - 1] < $vb[$offset + $k + 1])) {
$x = $vb[$offset + $k + 1];
var_dump($x);
} else {
$x = $vb[$offset + $k - 1] + 1;
}

$y = $x - $k;
$xs = $x;
$ys = $y;

while ($x < $n && $y < $m && $a[$aLo + $n - 1 - $x] === $b[$bLo + $m - 1 - $y]) {
$x++;
$y++;
}

$vb[$offset + $k] = $x;

if (!$deltaIsOdd) {
$kf = $delta - $k;

if ($kf >= -$d && $kf <= $d && $vf[$offset + $kf] + $vb[$offset + $k] >= $n) {
return [$n - $x, $m - $y, $n - $xs, $m - $ys];
}
}
}

return [];
}

$from = [3,2,1];
$to = [1,99,3];
findMiddleSnake($from, 0, count($from), $to, 0, count($to));
?>
--EXPECTF--
int(0)

Warning: Undefined array key 3 in %s on line %d
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