Partial constant folding in Accumulator

[ryukzak]

In test:

            , unitTestCase "target system: autosynthesis, constant folding 2" def $
                do
                    setNetwork march
                    setBusType pInt
                    assignLua
                        [__i|
                        function sum(a)
                            local d = a + 1 + 2
                            sum(d)
                        end
                        sum(0)
                        |]
                    optAccum <-
                        mkOptimizeAccum
                            [ add "_0#d" "!2#0" ["d^0#0"]
                            , add "a^0#0" "!1#0" ["_0#d"]
                            ]
                            [ acc
                                [ Push Plus $ I "a^0#0"
                                , Push Plus $ I "!1#0"
                                , Push Plus $ I "!2#0"
                                , Pull $ O $ S.fromList ["d^0#0"]
                                ]
                            ]
                    refactorAvail optAccum
                    refactor optAccum
                    assertRefactor optAccum
                -- FIXME: should be presented (with small changes)
                refactorAvail
                    =<< mkConstantFolding
                        [ acc
                            [ Push Plus $ I "a^0#0"
                            , Push Plus $ I "!1#0"
                            , Push Plus $ I "!2#0"
                            , Pull $ O $ S.fromList ["d^0#0"]
                            ]
                        , constant 1 ["!1#0"]
                        , constant 2 ["!2#0"]
                        ]
                        [ acc
                            [ Push Plus $ I "a^0#0"
                            , Push Plus $ I "_0#d"
                            , Pull $ O $ S.fromList ["d^0#0"]
                            ]
                        , constant 2 ["_0#d"]
                        ]

As you can see in the test, system doesn't see option for optimization inside Accum function (d = a + 1 + 2 -> d = a + 3). It should be implemented. How to do that:

• Implement ConstantFolding for Accum process unit (options).
• Implement decision propagation across bus network and target system.
• To see what happens in the test more clear -- use trace* functions.