// Copyright 2018 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package ssa import ( "fmt" "testing" ) const ( SetOrder = "SetOrder" SetOrder_Fail = "SetOrder_Fail" SetOrderOrEqual = "SetOrderOrEqual" SetOrderOrEqual_Fail = "SetOrderOrEqual_Fail" Ordered = "Ordered" Ordered_Fail = "Ordered_Fail" OrderedOrEqual = "OrderedOrEqual" OrderedOrEqual_Fail = "OrderedOrEqual_Fail" SetEqual = "SetEqual" SetEqual_Fail = "SetEqual_Fail" Equal = "Equal" Equal_Fail = "Equal_Fail" SetNonEqual = "SetNonEqual" SetNonEqual_Fail = "SetNonEqual_Fail" NonEqual = "NonEqual" NonEqual_Fail = "NonEqual_Fail" Checkpoint = "Checkpoint" Undo = "Undo" ) type posetTestOp struct { typ string a, b int } func vconst(i int) int { if i < -128 || i >= 128 { panic("invalid const") } return 1000 + 128 + i } func vconst2(i int) int { if i < -128 || i >= 128 { panic("invalid const") } return 1000 + 256 + i } func testPosetOps(t *testing.T, unsigned bool, ops []posetTestOp) { var v [1512]*Value for i := range v { v[i] = new(Value) v[i].ID = ID(i) if i >= 1000 && i < 1256 { v[i].Op = OpConst64 v[i].AuxInt = int64(i - 1000 - 128) } if i >= 1256 && i < 1512 { v[i].Op = OpConst64 v[i].AuxInt = int64(i - 1000 - 256) } } po := newPoset() po.SetUnsigned(unsigned) for idx, op := range ops { t.Logf("op%d%v", idx, op) switch op.typ { case SetOrder: if !po.SetOrder(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case SetOrder_Fail: if po.SetOrder(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case SetOrderOrEqual: if !po.SetOrderOrEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case SetOrderOrEqual_Fail: if po.SetOrderOrEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case Ordered: if !po.Ordered(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case Ordered_Fail: if po.Ordered(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case OrderedOrEqual: if !po.OrderedOrEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case OrderedOrEqual_Fail: if po.OrderedOrEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case SetEqual: if !po.SetEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case SetEqual_Fail: if po.SetEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case Equal: if !po.Equal(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case Equal_Fail: if po.Equal(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case SetNonEqual: if !po.SetNonEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case SetNonEqual_Fail: if po.SetNonEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case NonEqual: if !po.NonEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v failed", idx, op) } case NonEqual_Fail: if po.NonEqual(v[op.a], v[op.b]) { t.Errorf("FAILED: op%d%v passed", idx, op) } case Checkpoint: po.Checkpoint() case Undo: t.Log("Undo stack", po.undo) po.Undo() default: panic("unimplemented") } if false { po.DotDump(fmt.Sprintf("op%d.dot", idx), fmt.Sprintf("Last op: %v", op)) } po.CheckIntegrity() } // Check that the poset is completely empty if err := po.CheckEmpty(); err != nil { t.Error(err) } } func TestPoset(t *testing.T) { testPosetOps(t, false, []posetTestOp{ {Ordered_Fail, 123, 124}, // Dag #0: 100<101 {Checkpoint, 0, 0}, {SetOrder, 100, 101}, {Ordered, 100, 101}, {Ordered_Fail, 101, 100}, {SetOrder_Fail, 101, 100}, {SetOrder, 100, 101}, // repeat {NonEqual, 100, 101}, {NonEqual, 101, 100}, {SetEqual_Fail, 100, 101}, // Dag #1: 4<=7<12 {Checkpoint, 0, 0}, {SetOrderOrEqual, 4, 7}, {OrderedOrEqual, 4, 7}, {SetOrder, 7, 12}, {Ordered, 7, 12}, {Ordered, 4, 12}, {Ordered_Fail, 12, 4}, {NonEqual, 4, 12}, {NonEqual, 12, 4}, {NonEqual_Fail, 4, 100}, {OrderedOrEqual, 4, 12}, {OrderedOrEqual_Fail, 12, 4}, {OrderedOrEqual, 4, 7}, {OrderedOrEqual_Fail, 7, 4}, // Dag #1: 1<4<=7<12 {Checkpoint, 0, 0}, {SetOrder, 1, 4}, {Ordered, 1, 4}, {Ordered, 1, 12}, {Ordered_Fail, 12, 1}, // Dag #1: 1<4<=7<12, 6<7 {Checkpoint, 0, 0}, {SetOrder, 6, 7}, {Ordered, 6, 7}, {Ordered, 6, 12}, {SetOrder_Fail, 7, 4}, {SetOrder_Fail, 7, 6}, {SetOrder_Fail, 7, 1}, // Dag #1: 1<4<=7<12, 1<6<7 {Checkpoint, 0, 0}, {Ordered_Fail, 1, 6}, {SetOrder, 1, 6}, {Ordered, 1, 6}, {SetOrder_Fail, 6, 1}, // Dag #1: 1<4<=7<12, 1<4<6<7 {Checkpoint, 0, 0}, {Ordered_Fail, 4, 6}, {Ordered_Fail, 4, 7}, {SetOrder, 4, 6}, {Ordered, 4, 6}, {OrderedOrEqual, 4, 6}, {Ordered, 4, 7}, {OrderedOrEqual, 4, 7}, {SetOrder_Fail, 6, 4}, {Ordered_Fail, 7, 6}, {Ordered_Fail, 7, 4}, {OrderedOrEqual_Fail, 7, 6}, {OrderedOrEqual_Fail, 7, 4}, // Merge: 1<4<6, 4<=7<12, 6<101 {Checkpoint, 0, 0}, {Ordered_Fail, 6, 101}, {SetOrder, 6, 101}, {Ordered, 6, 101}, {Ordered, 1, 101}, // Merge: 1<4<6, 4<=7<12, 6<100<101 {Checkpoint, 0, 0}, {Ordered_Fail, 6, 100}, {SetOrder, 6, 100}, {Ordered, 1, 100}, // Undo: 1<4<6<7<12, 6<101 {Ordered, 100, 101}, {Undo, 0, 0}, {Ordered, 100, 101}, {Ordered_Fail, 6, 100}, {Ordered, 6, 101}, {Ordered, 1, 101}, // Undo: 1<4<6<7<12, 100<101 {Undo, 0, 0}, {Ordered_Fail, 1, 100}, {Ordered_Fail, 1, 101}, {Ordered_Fail, 6, 100}, {Ordered_Fail, 6, 101}, // Merge: 1<4<6<7<12, 6<100<101 {Checkpoint, 0, 0}, {Ordered, 100, 101}, {SetOrder, 6, 100}, {Ordered, 6, 100}, {Ordered, 6, 101}, {Ordered, 1, 101}, // Undo 2 times: 1<4<7<12, 1<6<7 {Undo, 0, 0}, {Undo, 0, 0}, {Ordered, 1, 6}, {Ordered, 4, 12}, {Ordered_Fail, 4, 6}, {SetOrder_Fail, 6, 1}, // Undo 2 times: 1<4<7<12 {Undo, 0, 0}, {Undo, 0, 0}, {Ordered, 1, 12}, {Ordered, 7, 12}, {Ordered_Fail, 1, 6}, {Ordered_Fail, 6, 7}, {Ordered, 100, 101}, {Ordered_Fail, 1, 101}, // Undo: 4<7<12 {Undo, 0, 0}, {Ordered_Fail, 1, 12}, {Ordered_Fail, 1, 4}, {Ordered, 4, 12}, {Ordered, 100, 101}, // Undo: 100<101 {Undo, 0, 0}, {Ordered_Fail, 4, 7}, {Ordered_Fail, 7, 12}, {Ordered, 100, 101}, // Recreated DAG #1 from scratch, reusing same nodes. // This also stresses that Undo has done its job correctly. // DAG: 1<2<(5|6), 101<102<(105|106<107) {Checkpoint, 0, 0}, {SetOrder, 101, 102}, {SetOrder, 102, 105}, {SetOrder, 102, 106}, {SetOrder, 106, 107}, {SetOrder, 1, 2}, {SetOrder, 2, 5}, {SetOrder, 2, 6}, {SetEqual_Fail, 1, 6}, {SetEqual_Fail, 107, 102}, // Now Set 2 == 102 // New DAG: (1|101)<2==102<(5|6|105|106<107) {Checkpoint, 0, 0}, {SetEqual, 2, 102}, {Equal, 2, 102}, {SetEqual, 2, 102}, // trivially pass {SetNonEqual_Fail, 2, 102}, // trivially fail {Ordered, 1, 107}, {Ordered, 101, 6}, {Ordered, 101, 105}, {Ordered, 2, 106}, {Ordered, 102, 6}, // Undo SetEqual {Undo, 0, 0}, {Equal_Fail, 2, 102}, {Ordered_Fail, 2, 102}, {Ordered_Fail, 1, 107}, {Ordered_Fail, 101, 6}, {Checkpoint, 0, 0}, {SetEqual, 2, 100}, {Ordered, 1, 107}, {Ordered, 100, 6}, // SetEqual with new node {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetEqual, 2, 400}, {SetEqual, 401, 2}, {Equal, 400, 401}, {Ordered, 1, 400}, {Ordered, 400, 6}, {Ordered, 1, 401}, {Ordered, 401, 6}, {Ordered_Fail, 2, 401}, // SetEqual unseen nodes and then connect {Checkpoint, 0, 0}, {SetEqual, 500, 501}, {SetEqual, 102, 501}, {Equal, 500, 102}, {Ordered, 501, 106}, {Ordered, 100, 500}, {SetEqual, 500, 501}, {Ordered_Fail, 500, 501}, {Ordered_Fail, 102, 501}, // SetNonEqual relations {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetNonEqual, 600, 601}, {NonEqual, 600, 601}, {SetNonEqual, 601, 602}, {NonEqual, 601, 602}, {NonEqual_Fail, 600, 602}, // non-transitive {SetEqual_Fail, 601, 602}, // Undo back to beginning, leave the poset empty {Undo, 0, 0}, {Undo, 0, 0}, {Undo, 0, 0}, {Undo, 0, 0}, }) } func TestPosetStrict(t *testing.T) { testPosetOps(t, false, []posetTestOp{ {Checkpoint, 0, 0}, // Build: 20!=30, 10<20<=30<40. The 20<=30 will become 20<30. {SetNonEqual, 20, 30}, {SetOrder, 10, 20}, {SetOrderOrEqual, 20, 30}, // this is affected by 20!=30 {SetOrder, 30, 40}, {Ordered, 10, 30}, {Ordered, 20, 30}, {Ordered, 10, 40}, {OrderedOrEqual, 10, 30}, {OrderedOrEqual, 20, 30}, {OrderedOrEqual, 10, 40}, {Undo, 0, 0}, // Now do the opposite: first build the DAG and then learn non-equality {Checkpoint, 0, 0}, {SetOrder, 10, 20}, {SetOrderOrEqual, 20, 30}, // this is affected by 20!=30 {SetOrder, 30, 40}, {Ordered, 10, 30}, {Ordered_Fail, 20, 30}, {Ordered, 10, 40}, {OrderedOrEqual, 10, 30}, {OrderedOrEqual, 20, 30}, {OrderedOrEqual, 10, 40}, {Checkpoint, 0, 0}, {SetNonEqual, 20, 30}, {Ordered, 10, 30}, {Ordered, 20, 30}, {Ordered, 10, 40}, {OrderedOrEqual, 10, 30}, {OrderedOrEqual, 20, 30}, {OrderedOrEqual, 10, 40}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetOrderOrEqual, 30, 35}, {OrderedOrEqual, 20, 35}, {Ordered_Fail, 20, 35}, {SetNonEqual, 20, 35}, {Ordered, 20, 35}, {Undo, 0, 0}, // Learn <= and >= {Checkpoint, 0, 0}, {SetOrderOrEqual, 50, 60}, {SetOrderOrEqual, 60, 50}, {OrderedOrEqual, 50, 60}, {OrderedOrEqual, 60, 50}, {Ordered_Fail, 50, 60}, {Ordered_Fail, 60, 50}, {Equal, 50, 60}, {Equal, 60, 50}, {NonEqual_Fail, 50, 60}, {NonEqual_Fail, 60, 50}, {Undo, 0, 0}, {Undo, 0, 0}, }) } func TestPosetCollapse(t *testing.T) { testPosetOps(t, false, []posetTestOp{ {Checkpoint, 0, 0}, // Create a complex graph of <= relations among nodes between 10 and 25. {SetOrderOrEqual, 10, 15}, {SetOrderOrEqual, 15, 20}, {SetOrderOrEqual, 20, vconst(20)}, {SetOrderOrEqual, vconst(20), 25}, {SetOrderOrEqual, 10, 12}, {SetOrderOrEqual, 12, 16}, {SetOrderOrEqual, 16, vconst(20)}, {SetOrderOrEqual, 10, 17}, {SetOrderOrEqual, 17, 25}, {SetOrderOrEqual, 15, 18}, {SetOrderOrEqual, 18, vconst(20)}, {SetOrderOrEqual, 15, 19}, {SetOrderOrEqual, 19, 25}, // These are other paths not part of the main collapsing path {SetOrderOrEqual, 10, 11}, {SetOrderOrEqual, 11, 26}, {SetOrderOrEqual, 13, 25}, {SetOrderOrEqual, 100, 25}, {SetOrderOrEqual, 101, 15}, {SetOrderOrEqual, 102, 10}, {SetOrderOrEqual, 25, 103}, {SetOrderOrEqual, 20, 104}, {Checkpoint, 0, 0}, // Collapse everything by setting 10 >= 25: this should make everything equal {SetOrderOrEqual, 25, 10}, // Check that all nodes are pairwise equal now {Equal, 10, 12}, {Equal, 10, 15}, {Equal, 10, 16}, {Equal, 10, 17}, {Equal, 10, 18}, {Equal, 10, 19}, {Equal, 10, vconst(20)}, {Equal, 10, vconst2(20)}, {Equal, 10, 25}, {Equal, 12, 15}, {Equal, 12, 16}, {Equal, 12, 17}, {Equal, 12, 18}, {Equal, 12, 19}, {Equal, 12, vconst(20)}, {Equal, 12, vconst2(20)}, {Equal, 12, 25}, {Equal, 15, 16}, {Equal, 15, 17}, {Equal, 15, 18}, {Equal, 15, 19}, {Equal, 15, vconst(20)}, {Equal, 15, vconst2(20)}, {Equal, 15, 25}, {Equal, 16, 17}, {Equal, 16, 18}, {Equal, 16, 19}, {Equal, 16, vconst(20)}, {Equal, 16, vconst2(20)}, {Equal, 16, 25}, {Equal, 17, 18}, {Equal, 17, 19}, {Equal, 17, vconst(20)}, {Equal, 17, vconst2(20)}, {Equal, 17, 25}, {Equal, 18, 19}, {Equal, 18, vconst(20)}, {Equal, 18, vconst2(20)}, {Equal, 18, 25}, {Equal, 19, vconst(20)}, {Equal, 19, vconst2(20)}, {Equal, 19, 25}, {Equal, vconst(20), vconst2(20)}, {Equal, vconst(20), 25}, {Equal, vconst2(20), 25}, // ... but not 11/26/100/101/102, which were on a different path {Equal_Fail, 10, 11}, {Equal_Fail, 10, 26}, {Equal_Fail, 10, 100}, {Equal_Fail, 10, 101}, {Equal_Fail, 10, 102}, {OrderedOrEqual, 10, 26}, {OrderedOrEqual, 25, 26}, {OrderedOrEqual, 13, 25}, {OrderedOrEqual, 13, 10}, {Undo, 0, 0}, {OrderedOrEqual, 10, 25}, {Equal_Fail, 10, 12}, {Equal_Fail, 10, 15}, {Equal_Fail, 10, 25}, {Undo, 0, 0}, }) testPosetOps(t, false, []posetTestOp{ {Checkpoint, 0, 0}, {SetOrderOrEqual, 10, 15}, {SetOrderOrEqual, 15, 20}, {SetOrderOrEqual, 20, 25}, {SetOrder, 10, 16}, {SetOrderOrEqual, 16, 20}, // Check that we cannot collapse here because of the strict relation 10<16 {SetOrderOrEqual_Fail, 20, 10}, {Undo, 0, 0}, }) } func TestPosetSetEqual(t *testing.T) { testPosetOps(t, false, []posetTestOp{ // 10<=20<=30<40, 20<=100<110 {Checkpoint, 0, 0}, {SetOrderOrEqual, 10, 20}, {SetOrderOrEqual, 20, 30}, {SetOrder, 30, 40}, {SetOrderOrEqual, 20, 100}, {SetOrder, 100, 110}, {OrderedOrEqual, 10, 30}, {OrderedOrEqual_Fail, 30, 10}, {Ordered_Fail, 10, 30}, {Ordered_Fail, 30, 10}, {Ordered, 10, 40}, {Ordered_Fail, 40, 10}, // Try learning 10==20. {Checkpoint, 0, 0}, {SetEqual, 10, 20}, {OrderedOrEqual, 10, 20}, {Ordered_Fail, 10, 20}, {Equal, 10, 20}, {SetOrderOrEqual, 10, 20}, {SetOrderOrEqual, 20, 10}, {SetOrder_Fail, 10, 20}, {SetOrder_Fail, 20, 10}, {Undo, 0, 0}, // Try learning 20==10. {Checkpoint, 0, 0}, {SetEqual, 20, 10}, {OrderedOrEqual, 10, 20}, {Ordered_Fail, 10, 20}, {Equal, 10, 20}, {Undo, 0, 0}, // Try learning 10==40 or 30==40 or 10==110. {Checkpoint, 0, 0}, {SetEqual_Fail, 10, 40}, {SetEqual_Fail, 40, 10}, {SetEqual_Fail, 30, 40}, {SetEqual_Fail, 40, 30}, {SetEqual_Fail, 10, 110}, {SetEqual_Fail, 110, 10}, {Undo, 0, 0}, // Try learning 40==110, and then 10==40 or 10=110 {Checkpoint, 0, 0}, {SetEqual, 40, 110}, {SetEqual_Fail, 10, 40}, {SetEqual_Fail, 40, 10}, {SetEqual_Fail, 10, 110}, {SetEqual_Fail, 110, 10}, {Undo, 0, 0}, // Try learning 40<20 or 30<20 or 110<10 {Checkpoint, 0, 0}, {SetOrder_Fail, 40, 20}, {SetOrder_Fail, 30, 20}, {SetOrder_Fail, 110, 10}, {Undo, 0, 0}, // Try learning 30<=20 {Checkpoint, 0, 0}, {SetOrderOrEqual, 30, 20}, {Equal, 30, 20}, {OrderedOrEqual, 30, 100}, {Ordered, 30, 110}, {Undo, 0, 0}, {Undo, 0, 0}, }) } func TestPosetConst(t *testing.T) { testPosetOps(t, false, []posetTestOp{ {Checkpoint, 0, 0}, {SetOrder, 1, vconst(15)}, {SetOrderOrEqual, 100, vconst(120)}, {Ordered, 1, vconst(15)}, {Ordered, 1, vconst(120)}, {OrderedOrEqual, 1, vconst(120)}, {OrderedOrEqual, 100, vconst(120)}, {Ordered_Fail, 100, vconst(15)}, {Ordered_Fail, vconst(15), 100}, {Checkpoint, 0, 0}, {SetOrderOrEqual, 1, 5}, {SetOrderOrEqual, 5, 25}, {SetEqual, 20, vconst(20)}, {SetEqual, 25, vconst(25)}, {Ordered, 1, 20}, {Ordered, 1, vconst(30)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetOrderOrEqual, 1, 5}, {SetOrderOrEqual, 5, 25}, {SetEqual, vconst(-20), 5}, {SetEqual, vconst(-25), 1}, {Ordered, 1, 5}, {Ordered, vconst(-30), 1}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetNonEqual, 1, vconst(4)}, {SetNonEqual, 1, vconst(6)}, {NonEqual, 1, vconst(4)}, {NonEqual_Fail, 1, vconst(5)}, {NonEqual, 1, vconst(6)}, {Equal_Fail, 1, vconst(4)}, {Equal_Fail, 1, vconst(5)}, {Equal_Fail, 1, vconst(6)}, {Equal_Fail, 1, vconst(7)}, {Undo, 0, 0}, {Undo, 0, 0}, }) testPosetOps(t, true, []posetTestOp{ {Checkpoint, 0, 0}, {SetOrder, 1, vconst(15)}, {SetOrderOrEqual, 100, vconst(-5)}, // -5 is a very big number in unsigned {Ordered, 1, vconst(15)}, {Ordered, 1, vconst(-5)}, {OrderedOrEqual, 1, vconst(-5)}, {OrderedOrEqual, 100, vconst(-5)}, {Ordered_Fail, 100, vconst(15)}, {Ordered_Fail, vconst(15), 100}, {Undo, 0, 0}, }) testPosetOps(t, false, []posetTestOp{ {Checkpoint, 0, 0}, {SetOrderOrEqual, 1, vconst(3)}, {SetNonEqual, 1, vconst(0)}, {Ordered_Fail, 1, vconst(0)}, {Undo, 0, 0}, }) testPosetOps(t, false, []posetTestOp{ // Check relations of a constant with itself {Checkpoint, 0, 0}, {SetOrderOrEqual, vconst(3), vconst2(3)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetEqual, vconst(3), vconst2(3)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetNonEqual_Fail, vconst(3), vconst2(3)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetOrder_Fail, vconst(3), vconst2(3)}, {Undo, 0, 0}, // Check relations of two constants among them, using // different instances of the same constant {Checkpoint, 0, 0}, {SetOrderOrEqual, vconst(3), vconst(4)}, {OrderedOrEqual, vconst(3), vconst2(4)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetOrder, vconst(3), vconst(4)}, {Ordered, vconst(3), vconst2(4)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetEqual_Fail, vconst(3), vconst(4)}, {SetEqual_Fail, vconst(3), vconst2(4)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {NonEqual, vconst(3), vconst(4)}, {NonEqual, vconst(3), vconst2(4)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {Equal_Fail, vconst(3), vconst(4)}, {Equal_Fail, vconst(3), vconst2(4)}, {Undo, 0, 0}, {Checkpoint, 0, 0}, {SetNonEqual, vconst(3), vconst(4)}, {SetNonEqual, vconst(3), vconst2(4)}, {Undo, 0, 0}, }) } func TestPosetNonEqual(t *testing.T) { testPosetOps(t, false, []posetTestOp{ {Equal_Fail, 10, 20}, {NonEqual_Fail, 10, 20}, // Learn 10!=20 {Checkpoint, 0, 0}, {SetNonEqual, 10, 20}, {Equal_Fail, 10, 20}, {NonEqual, 10, 20}, {SetEqual_Fail, 10, 20}, // Learn again 10!=20 {Checkpoint, 0, 0}, {SetNonEqual, 10, 20}, {Equal_Fail, 10, 20}, {NonEqual, 10, 20}, // Undo. We still know 10!=20 {Undo, 0, 0}, {Equal_Fail, 10, 20}, {NonEqual, 10, 20}, {SetEqual_Fail, 10, 20}, // Undo again. Now we know nothing {Undo, 0, 0}, {Equal_Fail, 10, 20}, {NonEqual_Fail, 10, 20}, // Learn 10==20 {Checkpoint, 0, 0}, {SetEqual, 10, 20}, {Equal, 10, 20}, {NonEqual_Fail, 10, 20}, {SetNonEqual_Fail, 10, 20}, // Learn again 10==20 {Checkpoint, 0, 0}, {SetEqual, 10, 20}, {Equal, 10, 20}, {NonEqual_Fail, 10, 20}, {SetNonEqual_Fail, 10, 20}, // Undo. We still know 10==20 {Undo, 0, 0}, {Equal, 10, 20}, {NonEqual_Fail, 10, 20}, {SetNonEqual_Fail, 10, 20}, // Undo. We know nothing {Undo, 0, 0}, {Equal_Fail, 10, 20}, {NonEqual_Fail, 10, 20}, }) }