Re-enable SimplifyToExp in match_branches

Author: dianqk

compiler/rustc_mir_transform/src/match_branches.rs

@@ -41,10 +41,7 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
                 should_cleanup = true;
                 continue;
             }
-            // unsound: https://github.com/rust-lang/rust/issues/124150
-            if tcx.sess.opts.unstable_opts.unsound_mir_opts
-                && SimplifyToExp::default().simplify(tcx, body, bb_idx, param_env).is_some()
-            {
+            if SimplifyToExp::default().simplify(tcx, body, bb_idx, param_env).is_some() {
                 should_cleanup = true;
                 continue;
             }