Function unreachable_node

cranelift/codegen/src/dominator_tree.rs:596–647

()

    #[test]
    fn unreachable_node() {
        let mut func = Function::new();
        let block0 = func.dfg.make_block();
        let v0 = func.dfg.append_block_param(block0, I32);
        let block1 = func.dfg.make_block();
        let block2 = func.dfg.make_block();
        let trap_block = func.dfg.make_block();

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

        cur.insert_block(block0);
        cur.ins().brif(v0, block2, &[], trap_block, &[]);

        cur.insert_block(trap_block);
        cur.ins().trap(TrapCode::unwrap_user(1));

        cur.insert_block(block1);
        let v1 = cur.ins().iconst(I32, 1);
        let v2 = cur.ins().iadd(v0, v1);
        cur.ins().jump(block0, &[v2.into()]);

        cur.insert_block(block2);
        cur.ins().return_(&[v0]);

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

        // Fall-through-first, prune-at-source DFT:
        //
        // block0 {
        //   brif block2 {
        //     trap
        //     block2 {
        //       return
        //     } block2
        // } block0
        assert_eq!(dt.cfg_postorder(), &[block2, trap_block, block0]);

        let v2_def = cur.func.dfg.value_def(v2).unwrap_inst();
        assert!(!dt.dominates(v2_def, block0, &cur.func.layout));
        assert!(!dt.dominates(block0, v2_def, &cur.func.layout));

        assert!(dt.block_dominates(block0, block0));
        assert!(!dt.block_dominates(block0, block1));
        assert!(dt.block_dominates(block0, block2));
        assert!(!dt.block_dominates(block1, block0));
        assert!(dt.block_dominates(block1, block1));
        assert!(!dt.block_dominates(block1, block2));
        assert!(!dt.block_dominates(block2, block0));
        assert!(!dt.block_dominates(block2, block1));
        assert!(dt.block_dominates(block2, block2));
    }

    #[test]
    fn non_zero_entry_block() {