Disable stack2reg optimization

bjorn3 · bjorn3 · commit 92c1b858ef78 · 2021-02-20T16:55:30.000+01:00
It causes a miscompilation of lewton Fixes #1142
diff --git a/src/optimize/mod.rs b/src/optimize/mod.rs
@@ -19,7 +19,12 @@ pub(crate) fn optimize_function<'tcx>(
     if tcx.sess.opts.optimize == rustc_session::config::OptLevel::No {
         return; // FIXME classify optimizations over opt levels
     }
-    self::stack2reg::optimize_function(ctx, clif_comments);
+
+    // FIXME(#1142) stack2reg miscompiles lewton
+    if false {
+        self::stack2reg::optimize_function(ctx, clif_comments);
+    }
+
     crate::pretty_clif::write_clif_file(tcx, "stack2reg", None, instance, &ctx, &*clif_comments);
     crate::base::verify_func(tcx, &*clif_comments, &ctx.func);
 }

Original file line number	Diff line number	Diff line change
`@@ -19,7 +19,12 @@ pub(crate) fn optimize_function<'tcx>(`
`19`	`19`	`if tcx.sess.opts.optimize == rustc_session::config::OptLevel::No {`
`20`	`20`	`return; // FIXME classify optimizations over opt levels`
`21`	`21`	`}`
`22`		`- self::stack2reg::optimize_function(ctx, clif_comments);`
	`22`	`+`
	`23`	`+ // FIXME(#1142) stack2reg miscompiles lewton`
	`24`	`+ if false {`
	`25`	`+ self::stack2reg::optimize_function(ctx, clif_comments);`
	`26`	`+ }`
	`27`	`+`
`23`	`28`	`crate::pretty_clif::write_clif_file(tcx, "stack2reg", None, instance, &ctx, &*clif_comments);`
`24`	`29`	`crate::base::verify_func(tcx, &*clif_comments, &ctx.func);`
`25`	`30`	`}`