Function backwards_layout

cranelift/codegen/src/dominator_tree.rs:710–776

()

    #[test]
    fn backwards_layout() {
        let mut func = Function::new();
        let block0 = func.dfg.make_block();
        let block1 = func.dfg.make_block();
        let block2 = func.dfg.make_block();

        let mut cur = FuncCursor::new(&mut func);

        cur.insert_block(block0);
        let jmp02 = cur.ins().jump(block2, &[]);

        cur.insert_block(block1);
        let trap = cur.ins().trap(TrapCode::unwrap_user(5));

        cur.insert_block(block2);
        let jmp21 = cur.ins().jump(block1, &[]);

        let cfg = ControlFlowGraph::with_function(cur.func);
        let dt = DominatorTree::with_function(cur.func, &cfg);

        assert_eq!(cur.func.layout.entry_block(), Some(block0));
        assert_eq!(dt.idom(block0), None);
        assert_eq!(dt.idom(block1), Some(block2));
        assert_eq!(dt.idom(block2), Some(block0));

        assert!(dt.dominates(block0, block0, &cur.func.layout));
        assert!(dt.dominates(block0, jmp02, &cur.func.layout));
        assert!(dt.dominates(block0, block1, &cur.func.layout));
        assert!(dt.dominates(block0, trap, &cur.func.layout));
        assert!(dt.dominates(block0, block2, &cur.func.layout));
        assert!(dt.dominates(block0, jmp21, &cur.func.layout));

        assert!(!dt.dominates(jmp02, block0, &cur.func.layout));
        assert!(dt.dominates(jmp02, jmp02, &cur.func.layout));
        assert!(dt.dominates(jmp02, block1, &cur.func.layout));
        assert!(dt.dominates(jmp02, trap, &cur.func.layout));
        assert!(dt.dominates(jmp02, block2, &cur.func.layout));
        assert!(dt.dominates(jmp02, jmp21, &cur.func.layout));

        assert!(!dt.dominates(block1, block0, &cur.func.layout));
        assert!(!dt.dominates(block1, jmp02, &cur.func.layout));
        assert!(dt.dominates(block1, block1, &cur.func.layout));
        assert!(dt.dominates(block1, trap, &cur.func.layout));
        assert!(!dt.dominates(block1, block2, &cur.func.layout));
        assert!(!dt.dominates(block1, jmp21, &cur.func.layout));

        assert!(!dt.dominates(trap, block0, &cur.func.layout));
        assert!(!dt.dominates(trap, jmp02, &cur.func.layout));
        assert!(!dt.dominates(trap, block1, &cur.func.layout));
        assert!(dt.dominates(trap, trap, &cur.func.layout));
        assert!(!dt.dominates(trap, block2, &cur.func.layout));
        assert!(!dt.dominates(trap, jmp21, &cur.func.layout));

        assert!(!dt.dominates(block2, block0, &cur.func.layout));
        assert!(!dt.dominates(block2, jmp02, &cur.func.layout));
        assert!(dt.dominates(block2, block1, &cur.func.layout));
        assert!(dt.dominates(block2, trap, &cur.func.layout));
        assert!(dt.dominates(block2, block2, &cur.func.layout));