Disable JIT by default, make it opt-in via --force-jit

alies-dev · danog · commit b64036069ec8 · 2026-03-17T11:43:19.000+01:00
Benchmarks across multiple platforms (Windows, Linux, macOS) and codebases consistently show JIT hurting Psalm performance by 5-35%. Additionally, JIT causes segfaults during taint analysis on certain platforms due to PHP core JIT bugs. Split opcache settings into base (always applied) and JIT-specific (only applied when --force-jit or forceJit="true" is set). This keeps opcache optimizations while avoiding JIT overhead and instability by default. Refs #11589, #11613
diff --git a/src/Psalm/Internal/Cli/Psalm.php b/src/Psalm/Internal/Cli/Psalm.php
@@ -1013,7 +1013,7 @@ private static function restart(
                     . 'You can enable JIT acceleration (experimental) with --force-jit.'
                     . PHP_EOL . PHP_EOL);
             }
-        } else {
+        } elseif ($force_jit) {
             $progress->write(PHP_EOL
                 . 'JIT acceleration: OFF (opcache not installed or not enabled)' . PHP_EOL
                 . 'Install and enable the opcache extension to use JIT with --force-jit.'

Original file line number	Diff line number	Diff line change
`@@ -1013,7 +1013,7 @@ private static function restart(`
`1013`	`1013`	`. 'You can enable JIT acceleration (experimental) with --force-jit.'`
`1014`	`1014`	`. PHP_EOL . PHP_EOL);`
`1015`	`1015`	`}`
`1016`		`- } else {`
	`1016`	`+ } elseif ($force_jit) {`
`1017`	`1017`	`$progress->write(PHP_EOL`
`1018`	`1018`	`. 'JIT acceleration: OFF (opcache not installed or not enabled)' . PHP_EOL`
`1019`	`1019`	`. 'Install and enable the opcache extension to use JIT with --force-jit.'`