Function replace_with_imm_method

cranelift/codegen/src/ir/builder.rs:362–392

()

    #[test]
    fn replace_with_imm_method() {
        // Replacing an instruction with a generated `*_imm` convenience method
        // (here `icmp_imm`) must materialize its `iconst` immediately before the
        // replaced instruction via `ReplaceBuilder::build_aux_inst`.
        let mut func = Function::new();
        let block0 = func.dfg.make_block();
        let arg0 = func.dfg.append_block_param(block0, I32);
        {
            let mut pos = FuncCursor::new(&mut func);
            pos.insert_block(block0);
            // A placeholder `icmp` (also `i8`-typed) to be replaced.
            pos.ins().icmp(IntCC::Equal, arg0, arg0);
        }

        let inst = func.layout.last_inst(block0).unwrap();
        assert_eq!(func.dfg.insts[inst].opcode(), Opcode::Icmp);

        let result = func.replace(inst).icmp_imm(IntCC::Equal, arg0, 42);

        // The replaced instruction is still an `icmp`, now comparing against a
        // freshly materialized constant.
        assert_eq!(func.dfg.insts[inst].opcode(), Opcode::Icmp);
        assert_eq!(func.dfg.value_type(result), I8);

        // An `iconst.i32 42` was inserted immediately before the replaced inst.
        let iconst = func.layout.prev_inst(inst).unwrap();
        assert_eq!(func.dfg.insts[iconst].opcode(), Opcode::Iconst);
        let iconst_result = func.dfg.first_result(iconst);
        assert_eq!(func.dfg.value_type(iconst_result), I32);
        assert_eq!(func.dfg.inst_args(inst), &[arg0, iconst_result]);
    }

    #[test]
    #[should_panic]