Function complex_loop_detection

cranelift/codegen/src/loop_analysis.rs:370–431

()

    #[test]
    fn complex_loop_detection() {
        let mut func = Function::new();
        let block0 = func.dfg.make_block();
        let block1 = func.dfg.make_block();
        let block2 = func.dfg.make_block();
        let block3 = func.dfg.make_block();
        let block4 = func.dfg.make_block();
        let block5 = func.dfg.make_block();
        let block6 = func.dfg.make_block();
        let cond = func.dfg.append_block_param(block0, types::I32);

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

            cur.insert_block(block0);
            cur.ins().brif(cond, block1, &[], block3, &[]);

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

            cur.insert_block(block2);
            cur.ins().brif(cond, block1, &[], block5, &[]);

            cur.insert_block(block3);
            cur.ins().jump(block4, &[]);

            cur.insert_block(block4);
            cur.ins().brif(cond, block3, &[], block5, &[]);

            cur.insert_block(block5);
            cur.ins().brif(cond, block0, &[], block6, &[]);

            cur.insert_block(block6);
            cur.ins().return_(&[]);
        }

        let mut loop_analysis = LoopAnalysis::new();
        let cfg = ControlFlowGraph::with_function(&func);
        let domtree = DominatorTree::with_function(&func, &cfg);
        loop_analysis.compute(&func, &cfg, &domtree);

        let loops = loop_analysis.loops().collect::<Vec<Loop>>();
        assert_eq!(loops.len(), 3);
        assert_eq!(loop_analysis.loop_header(loops[0]), block0);
        assert_eq!(loop_analysis.loop_header(loops[1]), block3);
        assert_eq!(loop_analysis.loop_header(loops[2]), block1);
        assert_eq!(loop_analysis.loop_parent(loops[1]), Some(loops[0]));
        assert_eq!(loop_analysis.loop_parent(loops[2]), Some(loops[0]));
        assert_eq!(loop_analysis.loop_parent(loops[0]), None);
        assert_eq!(loop_analysis.is_in_loop(block0, loops[0]), true);
        assert_eq!(loop_analysis.is_in_loop(block1, loops[2]), true);
        assert_eq!(loop_analysis.is_in_loop(block2, loops[2]), true);
        assert_eq!(loop_analysis.is_in_loop(block3, loops[1]), true);
        assert_eq!(loop_analysis.is_in_loop(block4, loops[1]), true);
        assert_eq!(loop_analysis.is_in_loop(block5, loops[0]), true);
        assert_eq!(loop_analysis.loop_level(block0).level(), 1);
        assert_eq!(loop_analysis.loop_level(block1).level(), 2);
        assert_eq!(loop_analysis.loop_level(block2).level(), 2);