Bug #79860 [NEW]: Misoptimization under preloading

From: nikic Operating system: PHP version: 7.4.8 Package: opcache Bug Type: Bug Bug description:Misoptimization under preloading Description: ------------ Test case gets misoptimized under preloading, because the optimization pipeline runs twice. This happens during the second run of pass 9 (tmpvars): $_main: ; (lines=27, args=0, vars=6, tmps=5) ; (after pass 5) ; /home/nikic/php/php-src/t049.php:1-10 ; return [] RANGE[0..0] 0000 ASSIGN CV0($multi) array(...) 0001 V6 = FE_RESET_R CV0($multi) 0025 0002 T7 = FE_FETCH_R V6 V8 0025 0003 V9 = FETCH_LIST_R V8 int(0) 0004 V10 = FETCH_LIST_R V9 int(0) 0005 ASSIGN CV1($a) V10 0006 V10 = FETCH_LIST_R V9 int(1) 0007 ASSIGN CV2($b) V10 0008 FREE V9 0009 V9 = FETCH_LIST_R V8 int(1) 0010 V10 = FETCH_LIST_R V9 int(0) 0011 ASSIGN CV3($c) V10 0012 V10 = FETCH_LIST_R V9 int(1) 0013 ASSIGN CV4($d) V10 0014 FREE V9 0015 FREE V8 0016 ASSIGN CV5($key) T7 0017 INIT_FCALL 1 96 string("var_dump") 0018 T8 = CONCAT CV5($key) CV1($a) 0019 T7 = CONCAT T8 CV2($b) 0020 T8 = CONCAT T7 CV3($c) 0021 T7 = CONCAT T8 CV4($d) 0022 SEND_VAL T7 1 0023 DO_ICALL 0024 JMP 0002 0025 FE_FREE V6 0026 RETURN int(1) $_main: ; (lines=27, args=0, vars=6, tmps=4) ; (after pass 9) ; /home/nikic/php/php-src/t049.php:1-10 ; return [] RANGE[0..0] 0000 ASSIGN CV0($multi) array(...) 0001 V6 = FE_RESET_R CV0($multi) 0025 0002 T7 = FE_FETCH_R V6 V8 0025 0003 V8 = FETCH_LIST_R V8 int(0) 0004 V9 = FETCH_LIST_R V8 int(0) 0005 ASSIGN CV1($a) V9 0006 V9 = FETCH_LIST_R V8 int(1) 0007 ASSIGN CV2($b) V9 0008 FREE V8 0009 V8 = FETCH_LIST_R V8 int(1) 0010 V9 = FETCH_LIST_R V8 int(0) 0011 ASSIGN CV3($c) V9 0012 V9 = FETCH_LIST_R V8 int(1) 0013 ASSIGN CV4($d) V9 0014 FREE V8 0015 FREE V8 0016 ASSIGN CV5($key) T7 0017 INIT_FCALL 1 96 string("var_dump") 0018 T8 = CONCAT CV5($key) CV1($a) 0019 T7 = CONCAT T8 CV2($b) 0020 T8 = CONCAT T7 CV3($c) 0021 T7 = CONCAT T8 CV4($d) 0022 SEND_VAL T7 1 0023 DO_ICALL 0024 JMP 0002 0025 FE_FREE V6 0026 RETURN int(1) Test script: --------------- <?php $multi = array( array(array(1,2), array(3,4)), ); foreach ($multi as list(list($a, $b), list($c, $d))) { var_dump($a . $b . $c . $d); } Expected result: ---------------- string(4) "1234" Actual result: -------------- string(2) "12" -- Edit bug report at https://bugs.php.net/bug.php?id=79860&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=79860&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=79860&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=79860&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=79860&r=needscript Try newer version: https://bugs.php.net/fix.php?id=79860&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=79860&r=support Expected behavior: https://bugs.php.net/fix.php?id=79860&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=79860&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=79860&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=79860&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=79860&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=79860&r=dst IIS Stability: https://bugs.php.net/fix.php?id=79860&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=79860&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=79860&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=79860&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=79860&r=mysqlcfg