runtime/vm/compiler/backend/redundancy_elimination_test.cc

// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "vm/compiler/backend/redundancy_elimination.h"

#include <functional>

#include "vm/compiler/backend/block_builder.h"
#include "vm/compiler/backend/il_printer.h"
#include "vm/compiler/backend/il_test_helper.h"
#include "vm/compiler/backend/inliner.h"
#include "vm/compiler/backend/loops.h"
#include "vm/compiler/backend/type_propagator.h"
#include "vm/compiler/compiler_pass.h"
#include "vm/compiler/frontend/kernel_to_il.h"
#include "vm/compiler/jit/jit_call_specializer.h"
#include "vm/flags.h"
#include "vm/kernel_isolate.h"
#include "vm/log.h"
#include "vm/object.h"
#include "vm/parser.h"
#include "vm/symbols.h"
#include "vm/unit_test.h"

namespace dart {

static void NoopNative(Dart_NativeArguments args) {}

static Dart_NativeFunction NoopNativeLookup(Dart_Handle name,
                                            int argument_count,
                                            bool* auto_setup_scope) {
  ASSERT(auto_setup_scope != nullptr);
  *auto_setup_scope = false;
  return NoopNative;
}

// Flatten all non-captured LocalVariables from the given scope and its children
// and siblings into the given array based on their environment index.
static void FlattenScopeIntoEnvironment(FlowGraph* graph,
                                        LocalScope* scope,
                                        GrowableArray<LocalVariable*>* env) {
  for (intptr_t i = 0; i < scope->num_variables(); i++) {
    auto var = scope->VariableAt(i);
    if (var->is_captured()) {
      continue;
    }

    auto index = graph->EnvIndex(var);
    env->EnsureLength(index + 1, nullptr);
    (*env)[index] = var;
  }

  if (scope->sibling() != nullptr) {
    FlattenScopeIntoEnvironment(graph, scope->sibling(), env);
  }
  if (scope->child() != nullptr) {
    FlattenScopeIntoEnvironment(graph, scope->child(), env);
  }
}

// Run TryCatchAnalyzer optimization on the function foo from the given script
// and check that the only variables from the given list are synchronized
// on catch entry.
static void TryCatchOptimizerTest(
    Thread* thread,
    const char* script_chars,
    std::initializer_list<const char*> synchronized) {
  // Load the script and exercise the code once.
  const auto& root_library =
      Library::Handle(LoadTestScript(script_chars, &NoopNativeLookup));
  Invoke(root_library, "main");

  // Build the flow graph.
  std::initializer_list<CompilerPass::Id> passes = {
      CompilerPass::kComputeSSA,      CompilerPass::kTypePropagation,
      CompilerPass::kApplyICData,     CompilerPass::kSelectRepresentations,
      CompilerPass::kTypePropagation, CompilerPass::kCanonicalize,
  };
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* graph = pipeline.RunPasses(passes);

  // Finally run TryCatchAnalyzer on the graph (in AOT mode).
  OptimizeCatchEntryStates(graph, /*is_aot=*/true);

  EXPECT_EQ(1, graph->graph_entry()->catch_entries().length());
  auto scope = graph->parsed_function().scope();

  GrowableArray<LocalVariable*> env;
  FlattenScopeIntoEnvironment(graph, scope, &env);

  for (intptr_t i = 0; i < env.length(); i++) {
    bool found = false;
    for (auto name : synchronized) {
      if (env[i]->name().Equals(name)) {
        found = true;
        break;
      }
    }
    if (!found) {
      env[i] = nullptr;
    }
  }

  CatchBlockEntryInstr* catch_entry = graph->graph_entry()->catch_entries()[0];

  // We should only synchronize state for variables from the synchronized list.
  for (auto defn : *catch_entry->initial_definitions()) {
    if (ParameterInstr* param = defn->AsParameter()) {
      EXPECT(0 <= param->index() && param->index() < env.length());
      EXPECT(env[param->index()] != nullptr);
    }
  }
}

//
// Tests for TryCatchOptimizer.
//

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Simple1) {
  const char* script_chars = R"(
      @pragma("vm:external-name", "BlackholeNative")
      external dynamic blackhole([dynamic val]);
      foo(int p) {
        var a = blackhole(), b = blackhole();
        try {
          blackhole([a, b]);
        } catch (e) {
          // nothing is used
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Simple2) {
  const char* script_chars = R"(
      @pragma("vm:external-name", "BlackholeNative")
      external dynamic blackhole([dynamic val]);
      foo(int p) {
        var a = blackhole(), b = blackhole();
        try {
          blackhole([a, b]);
        } catch (e) {
          // a should be synchronized
          blackhole(a);
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a"});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Cyclic1) {
  const char* script_chars = R"(
      @pragma("vm:external-name", "BlackholeNative")
      external dynamic blackhole([dynamic val]);
      foo(int p) {
        var a = blackhole(), b;
        for (var i = 0; i < 42; i++) {
          b = blackhole();
          try {
            blackhole([a, b]);
          } catch (e) {
            // a and i should be synchronized
          }
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a", "i"});
}

ISOLATE_UNIT_TEST_CASE(TryCatchOptimizer_DeadParameterElimination_Cyclic2) {
  const char* script_chars = R"(
      @pragma("vm:external-name", "BlackholeNative")
      external dynamic blackhole([dynamic val]);
      foo(int p) {
        var a = blackhole(), b = blackhole();
        for (var i = 0; i < 42; i++) {
          try {
            blackhole([a, b]);
          } catch (e) {
            // a, b and i should be synchronized
          }
        }
      }
      main() {
        foo(42);
      }
  )";

  TryCatchOptimizerTest(thread, script_chars, /*synchronized=*/{"a", "b", "i"});
}

// LoadOptimizer tests

// This family of tests verifies behavior of load forwarding when alias for an
// allocation A is created by creating a redefinition for it and then
// letting redefinition escape.
static void TestAliasingViaRedefinition(
    Thread* thread,
    bool make_it_escape,
    std::function<Definition*(CompilerState* S, FlowGraph*, Definition*)>
        make_redefinition) {
  const char* script_chars = R"(
    @pragma("vm:external-name", "BlackholeNative")
    external dynamic blackhole([a, b, c, d, e, f]);
    class K {
      var field;
    }
  )";
  const Library& lib =
      Library::Handle(LoadTestScript(script_chars, NoopNativeLookup));

  const Class& cls = Class::ZoneHandle(
      lib.LookupLocalClass(String::Handle(Symbols::New(thread, "K"))));
  const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
  EXPECT(err.IsNull());

  const Field& original_field = Field::Handle(
      cls.LookupField(String::Handle(Symbols::New(thread, "field"))));
  EXPECT(!original_field.IsNull());
  const Field& field = Field::Handle(original_field.CloneFromOriginal());

  const Function& blackhole =
      Function::ZoneHandle(GetFunction(lib, "blackhole"));

  using compiler::BlockBuilder;
  CompilerState S(thread, /*is_aot=*/false, /*is_optimizing=*/true);
  FlowGraphBuilderHelper H;

  // We are going to build the following graph:
  //
  // B0[graph_entry]
  // B1[function_entry]:
  //   v0 <- AllocateObject(class K)
  //   v1 <- LoadField(v0, K.field)
  //   v2 <- make_redefinition(v0)
  //   PushArgument(v1)
  // #if make_it_escape
  //   PushArgument(v2)
  // #endif
  //   v3 <- StaticCall(blackhole, v1, v2)
  //   v4 <- LoadField(v2, K.field)
  //   Return v4

  auto b1 = H.flow_graph()->graph_entry()->normal_entry();
  AllocateObjectInstr* v0;
  LoadFieldInstr* v1;
  StaticCallInstr* call;
  LoadFieldInstr* v4;
  ReturnInstr* ret;

  {
    BlockBuilder builder(H.flow_graph(), b1);
    auto& slot = Slot::Get(field, &H.flow_graph()->parsed_function());
    v0 = builder.AddDefinition(
        new AllocateObjectInstr(InstructionSource(), cls, S.GetNextDeoptId()));
    v1 = builder.AddDefinition(
        new LoadFieldInstr(new Value(v0), slot, InstructionSource()));
    auto v2 = builder.AddDefinition(make_redefinition(&S, H.flow_graph(), v0));
    auto args = new InputsArray(2);
    args->Add(new Value(v1));
    if (make_it_escape) {
      args->Add(new Value(v2));
    }
    call = builder.AddInstruction(new StaticCallInstr(
        InstructionSource(), blackhole, 0, Array::empty_array(), args,
        S.GetNextDeoptId(), 0, ICData::RebindRule::kStatic));
    v4 = builder.AddDefinition(
        new LoadFieldInstr(new Value(v2), slot, InstructionSource()));
    ret = builder.AddInstruction(new ReturnInstr(
        InstructionSource(), new Value(v4), S.GetNextDeoptId()));
  }
  H.FinishGraph();
  DominatorBasedCSE::Optimize(H.flow_graph());

  if (make_it_escape) {
    // Allocation must be considered aliased.
    EXPECT_PROPERTY(v0, !it.Identity().IsNotAliased());
  } else {
    // Allocation must be considered not-aliased.
    EXPECT_PROPERTY(v0, it.Identity().IsNotAliased());
  }

  // v1 should have been removed from the graph and replaced with constant_null.
  EXPECT_PROPERTY(v1, it.next() == nullptr && it.previous() == nullptr);
  EXPECT_PROPERTY(call, it.ArgumentAt(0) == H.flow_graph()->constant_null());

  if (make_it_escape) {
    // v4 however should not be removed from the graph, because v0 escapes into
    // blackhole.
    EXPECT_PROPERTY(v4, it.next() != nullptr && it.previous() != nullptr);
    EXPECT_PROPERTY(ret, it.value()->definition() == v4);
  } else {
    // If v0 it not aliased then v4 should also be removed from the graph.
    EXPECT_PROPERTY(v4, it.next() == nullptr && it.previous() == nullptr);
    EXPECT_PROPERTY(
        ret, it.value()->definition() == H.flow_graph()->constant_null());
  }
}

static Definition* MakeCheckNull(CompilerState* S,
                                 FlowGraph* flow_graph,
                                 Definition* defn) {
  return new CheckNullInstr(new Value(defn), String::ZoneHandle(),
                            S->GetNextDeoptId(), InstructionSource());
}

static Definition* MakeRedefinition(CompilerState* S,
                                    FlowGraph* flow_graph,
                                    Definition* defn) {
  return new RedefinitionInstr(new Value(defn));
}

static Definition* MakeAssertAssignable(CompilerState* S,
                                        FlowGraph* flow_graph,
                                        Definition* defn) {
  const auto& dst_type = AbstractType::ZoneHandle(Type::ObjectType());
  return new AssertAssignableInstr(InstructionSource(), new Value(defn),
                                   new Value(flow_graph->GetConstant(dst_type)),
                                   new Value(flow_graph->constant_null()),
                                   new Value(flow_graph->constant_null()),
                                   Symbols::Empty(), S->GetNextDeoptId());
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedefinitionAliasing_CheckNull_NoEscape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/false, MakeCheckNull);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedefinitionAliasing_CheckNull_Escape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/true, MakeCheckNull);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_RedefinitionAliasing_Redefinition_NoEscape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/false,
                              MakeRedefinition);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedefinitionAliasing_Redefinition_Escape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/true,
                              MakeRedefinition);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_RedefinitionAliasing_AssertAssignable_NoEscape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/false,
                              MakeAssertAssignable);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_RedefinitionAliasing_AssertAssignable_Escape) {
  TestAliasingViaRedefinition(thread, /*make_it_escape=*/true,
                              MakeAssertAssignable);
}

// This family of tests verifies behavior of load forwarding when alias for an
// allocation A is created by storing it into another object B and then
// either loaded from it ([make_it_escape] is true) or object B itself
// escapes ([make_host_escape] is true).
// We insert redefinition for object B to check that use list traversal
// correctly discovers all loads and stores from B.
static void TestAliasingViaStore(
    Thread* thread,
    bool make_it_escape,
    bool make_host_escape,
    std::function<Definition*(CompilerState* S, FlowGraph*, Definition*)>
        make_redefinition) {
  const char* script_chars = R"(
    @pragma("vm:external-name", "BlackholeNative")
    external dynamic blackhole([a, b, c, d, e, f]);
    class K {
      var field;
    }
  )";
  const Library& lib =
      Library::Handle(LoadTestScript(script_chars, NoopNativeLookup));

  const Class& cls = Class::ZoneHandle(
      lib.LookupLocalClass(String::Handle(Symbols::New(thread, "K"))));
  const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
  EXPECT(err.IsNull());

  const Field& original_field = Field::Handle(
      cls.LookupField(String::Handle(Symbols::New(thread, "field"))));
  EXPECT(!original_field.IsNull());
  const Field& field = Field::Handle(original_field.CloneFromOriginal());

  const Function& blackhole =
      Function::ZoneHandle(GetFunction(lib, "blackhole"));

  using compiler::BlockBuilder;
  CompilerState S(thread, /*is_aot=*/false, /*is_optimizing=*/true);
  FlowGraphBuilderHelper H;

  // We are going to build the following graph:
  //
  // B0[graph_entry]
  // B1[function_entry]:
  //   v0 <- AllocateObject(class K)
  //   v5 <- AllocateObject(class K)
  // #if !make_host_escape
  //   StoreField(v5 . K.field = v0)
  // #endif
  //   v1 <- LoadField(v0, K.field)
  //   v2 <- REDEFINITION(v5)
  //   PushArgument(v1)
  // #if make_it_escape
  //   v6 <- LoadField(v2, K.field)
  //   PushArgument(v6)
  // #elif make_host_escape
  //   StoreField(v2 . K.field = v0)
  //   PushArgument(v5)
  // #endif
  //   v3 <- StaticCall(blackhole, v1, v6)
  //   v4 <- LoadField(v0, K.field)
  //   Return v4

  auto b1 = H.flow_graph()->graph_entry()->normal_entry();
  AllocateObjectInstr* v0;
  AllocateObjectInstr* v5;
  LoadFieldInstr* v1;
  StaticCallInstr* call;
  LoadFieldInstr* v4;
  ReturnInstr* ret;

  {
    BlockBuilder builder(H.flow_graph(), b1);
    auto& slot = Slot::Get(field, &H.flow_graph()->parsed_function());
    v0 = builder.AddDefinition(
        new AllocateObjectInstr(InstructionSource(), cls, S.GetNextDeoptId()));
    v5 = builder.AddDefinition(
        new AllocateObjectInstr(InstructionSource(), cls, S.GetNextDeoptId()));
    if (!make_host_escape) {
      builder.AddInstruction(
          new StoreInstanceFieldInstr(slot, new Value(v5), new Value(v0),
                                      kEmitStoreBarrier, InstructionSource()));
    }
    v1 = builder.AddDefinition(
        new LoadFieldInstr(new Value(v0), slot, InstructionSource()));
    auto v2 = builder.AddDefinition(make_redefinition(&S, H.flow_graph(), v5));
    auto args = new InputsArray(2);
    args->Add(new Value(v1));
    if (make_it_escape) {
      auto v6 = builder.AddDefinition(
          new LoadFieldInstr(new Value(v2), slot, InstructionSource()));
      args->Add(new Value(v6));
    } else if (make_host_escape) {
      builder.AddInstruction(
          new StoreInstanceFieldInstr(slot, new Value(v2), new Value(v0),
                                      kEmitStoreBarrier, InstructionSource()));
      args->Add(new Value(v5));
    }
    call = builder.AddInstruction(new StaticCallInstr(
        InstructionSource(), blackhole, 0, Array::empty_array(), args,
        S.GetNextDeoptId(), 0, ICData::RebindRule::kStatic));
    v4 = builder.AddDefinition(
        new LoadFieldInstr(new Value(v0), slot, InstructionSource()));
    ret = builder.AddInstruction(new ReturnInstr(
        InstructionSource(), new Value(v4), S.GetNextDeoptId()));
  }
  H.FinishGraph();
  DominatorBasedCSE::Optimize(H.flow_graph());

  if (make_it_escape || make_host_escape) {
    // Allocation must be considered aliased.
    EXPECT_PROPERTY(v0, !it.Identity().IsNotAliased());
  } else {
    // Allocation must not be considered aliased.
    EXPECT_PROPERTY(v0, it.Identity().IsNotAliased());
  }

  if (make_host_escape) {
    EXPECT_PROPERTY(v5, !it.Identity().IsNotAliased());
  } else {
    EXPECT_PROPERTY(v5, it.Identity().IsNotAliased());
  }

  // v1 should have been removed from the graph and replaced with constant_null.
  EXPECT_PROPERTY(v1, it.next() == nullptr && it.previous() == nullptr);
  EXPECT_PROPERTY(call, it.ArgumentAt(0) == H.flow_graph()->constant_null());

  if (make_it_escape || make_host_escape) {
    // v4 however should not be removed from the graph, because v0 escapes into
    // blackhole.
    EXPECT_PROPERTY(v4, it.next() != nullptr && it.previous() != nullptr);
    EXPECT_PROPERTY(ret, it.value()->definition() == v4);
  } else {
    // If v0 it not aliased then v4 should also be removed from the graph.
    EXPECT_PROPERTY(v4, it.next() == nullptr && it.previous() == nullptr);
    EXPECT_PROPERTY(
        ret, it.value()->definition() == H.flow_graph()->constant_null());
  }
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_CheckNull_NoEscape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ false, MakeCheckNull);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_CheckNull_Escape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/true,
                       /* make_host_escape= */ false, MakeCheckNull);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_CheckNull_EscapeViaHost) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ true, MakeCheckNull);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_Redefinition_NoEscape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ false, MakeRedefinition);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_Redefinition_Escape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/true,
                       /* make_host_escape= */ false, MakeRedefinition);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_AliasingViaStore_Redefinition_EscapeViaHost) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ true, MakeRedefinition);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_AliasingViaStore_AssertAssignable_NoEscape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ false, MakeAssertAssignable);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaStore_AssertAssignable_Escape) {
  TestAliasingViaStore(thread, /*make_it_escape=*/true,
                       /* make_host_escape= */ false, MakeAssertAssignable);
}

ISOLATE_UNIT_TEST_CASE(
    LoadOptimizer_AliasingViaStore_AssertAssignable_EscapeViaHost) {
  TestAliasingViaStore(thread, /*make_it_escape=*/false,
                       /* make_host_escape= */ true, MakeAssertAssignable);
}

// This is a regression test for
// https://github.com/flutter/flutter/issues/48114.
ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaTypedDataAndUntaggedTypedData) {
  using compiler::BlockBuilder;
  CompilerState S(thread, /*is_aot=*/false, /*is_optimizing=*/true);
  FlowGraphBuilderHelper H;

  const auto& lib = Library::Handle(Library::TypedDataLibrary());
  const Class& cls = Class::Handle(lib.LookupLocalClass(Symbols::Uint32List()));
  const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
  EXPECT(err.IsNull());

  const Function& function = Function::ZoneHandle(
      cls.LookupFactory(String::Handle(String::New("Uint32List."))));
  EXPECT(!function.IsNull());

  auto zone = H.flow_graph()->zone();

  // We are going to build the following graph:
  //
  //   B0[graph_entry] {
  //     vc0 <- Constant(0)
  //     vc42 <- Constant(42)
  //   }
  //
  //   B1[function_entry] {
  //   }
  //   array <- StaticCall(...) {_Uint32List}
  //   v1 <- LoadIndexed(array)
  //   v2 <- LoadUntagged(array)
  //   StoreIndexed(v2, index=vc0, value=vc42)
  //   v3 <- LoadIndexed(array)
  //   return v3
  // }

  auto vc0 = H.flow_graph()->GetConstant(Integer::Handle(Integer::New(0)));
  auto vc42 = H.flow_graph()->GetConstant(Integer::Handle(Integer::New(42)));
  auto b1 = H.flow_graph()->graph_entry()->normal_entry();

  StaticCallInstr* array;
  LoadIndexedInstr* v1;
  LoadUntaggedInstr* v2;
  StoreIndexedInstr* store;
  LoadIndexedInstr* v3;
  ReturnInstr* ret;

  {
    BlockBuilder builder(H.flow_graph(), b1);

    //   array <- StaticCall(...) {_Uint32List}
    array = builder.AddDefinition(new StaticCallInstr(
        InstructionSource(), function, 0, Array::empty_array(),
        new InputsArray(), DeoptId::kNone, 0, ICData::kNoRebind));
    array->UpdateType(CompileType::FromCid(kTypedDataUint32ArrayCid));
    array->SetResultType(zone, CompileType::FromCid(kTypedDataUint32ArrayCid));
    array->set_is_known_list_constructor(true);

    //   v1 <- LoadIndexed(array)
    v1 = builder.AddDefinition(new LoadIndexedInstr(
        new Value(array), new Value(vc0), /*index_unboxed=*/false, 1,
        kTypedDataUint32ArrayCid, kAlignedAccess, DeoptId::kNone,
        InstructionSource()));

    //   v2 <- LoadUntagged(array)
    //   StoreIndexed(v2, index=0, value=42)
    v2 = builder.AddDefinition(new LoadUntaggedInstr(new Value(array), 0));
    store = builder.AddInstruction(new StoreIndexedInstr(
        new Value(v2), new Value(vc0), new Value(vc42), kNoStoreBarrier,
        /*index_unboxed=*/false, 1, kTypedDataUint32ArrayCid, kAlignedAccess,
        DeoptId::kNone, InstructionSource()));

    //   v3 <- LoadIndexed(array)
    v3 = builder.AddDefinition(new LoadIndexedInstr(
        new Value(array), new Value(vc0), /*index_unboxed=*/false, 1,
        kTypedDataUint32ArrayCid, kAlignedAccess, DeoptId::kNone,
        InstructionSource()));

    //   return v3
    ret = builder.AddInstruction(new ReturnInstr(
        InstructionSource(), new Value(v3), S.GetNextDeoptId()));
  }
  H.FinishGraph();

  DominatorBasedCSE::Optimize(H.flow_graph());
  {
    Instruction* sc = nullptr;
    Instruction* li = nullptr;
    Instruction* lu = nullptr;
    Instruction* s = nullptr;
    Instruction* li2 = nullptr;
    Instruction* r = nullptr;
    ILMatcher cursor(H.flow_graph(), b1, true);
    RELEASE_ASSERT(cursor.TryMatch({
        kMatchAndMoveFunctionEntry,
        {kMatchAndMoveStaticCall, &sc},
        {kMatchAndMoveLoadIndexed, &li},
        {kMatchAndMoveLoadUntagged, &lu},
        {kMatchAndMoveStoreIndexed, &s},
        {kMatchAndMoveLoadIndexed, &li2},
        {kMatchReturn, &r},
    }));
    EXPECT(array == sc);
    EXPECT(v1 == li);
    EXPECT(v2 == lu);
    EXPECT(store == s);
    EXPECT(v3 == li2);
    EXPECT(ret == r);
  }
}

// This test verifies behavior of load forwarding when an alias for an
// allocation A is created after forwarded due to an eliminated load. That is,
// allocation A is stored and later retrieved via load B, B is used in store C
// (with a different constant index/index_scale than in B but that overlaps),
// and then A is retrieved again (with the same index as in B) in load D.
//
// When B gets eliminated and replaced with in C and D with A, the store in C
// should stop the load D from being eliminated. This is a scenario that came
// up when forwarding typed data view factory arguments.
//
// Here, the entire scenario happens within a single basic block.
ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaLoadElimination_SingleBlock) {
  const char* kScript = R"(
    import 'dart:typed_data';

    testViewAliasing1() {
      final f64 = new Float64List(1);
      final f32 = new Float32List.view(f64.buffer);
      f64[0] = 1.0; // Should not be forwarded.
      f32[1] = 2.0; // upper 32bits for 2.0f and 2.0 are the same
      return f64[0];
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  const auto& function =
      Function::Handle(GetFunction(root_library, "testViewAliasing1"));

  Invoke(root_library, "testViewAliasing1");

  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({});

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  AllocateTypedDataInstr* alloc_typed_data = nullptr;
  StoreIndexedInstr* first_store = nullptr;
  StoreIndexedInstr* second_store = nullptr;
  LoadIndexedInstr* final_load = nullptr;
  BoxInstr* boxed_result = nullptr;

  ILMatcher cursor(flow_graph, entry);
  RELEASE_ASSERT(cursor.TryMatch(
      {
          {kMatchAndMoveAllocateTypedData, &alloc_typed_data},
          {kMatchAndMoveStoreIndexed, &first_store},
          {kMatchAndMoveStoreIndexed, &second_store},
          {kMatchAndMoveLoadIndexed, &final_load},
          {kMatchAndMoveBox, &boxed_result},
          kMatchReturn,
      },
      /*insert_before=*/kMoveGlob));

  EXPECT(first_store->array()->definition() == alloc_typed_data);
  EXPECT(second_store->array()->definition() == alloc_typed_data);
  EXPECT(boxed_result->value()->definition() == final_load);
}

// This test verifies behavior of load forwarding when an alias for an
// allocation A is created after forwarded due to an eliminated load. That is,
// allocation A is stored and later retrieved via load B, B is used in store C
// (with a different constant index/index_scale than in B but that overlaps),
// and then A is retrieved again (with the same index as in B) in load D.
//
// When B gets eliminated and replaced with in C and D with A, the store in C
// should stop the load D from being eliminated. This is a scenario that came
// up when forwarding typed data view factory arguments.
//
// Here, the scenario is split across basic blocks. This is a cut-down version
// of language_2/vm/load_to_load_forwarding_vm_test.dart with just enough extra
// to keep testViewAliasing1 from being optimized into a single basic block.
// Thus, this test may be brittler than the other, if future work causes it to
// end up compiled into a single basic block (or a simpler set of basic blocks).
ISOLATE_UNIT_TEST_CASE(LoadOptimizer_AliasingViaLoadElimination_AcrossBlocks) {
  const char* kScript = R"(
    import 'dart:typed_data';

    class Expect {
      static void equals(var a, var b) {}
      static void listEquals(var a, var b) {}
    }

    testViewAliasing1() {
      final f64 = new Float64List(1);
      final f32 = new Float32List.view(f64.buffer);
      f64[0] = 1.0; // Should not be forwarded.
      f32[1] = 2.0; // upper 32bits for 2.0f and 2.0 are the same
      return f64[0];
    }

    testViewAliasing2() {
      final f64 = new Float64List(2);
      final f64v = new Float64List.view(f64.buffer,
                                        Float64List.bytesPerElement);
      f64[1] = 1.0; // Should not be forwarded.
      f64v[0] = 2.0;
      return f64[1];
    }

    testViewAliasing3() {
      final u8 = new Uint8List(Float64List.bytesPerElement * 2);
      final f64 = new Float64List.view(u8.buffer, Float64List.bytesPerElement);
      f64[0] = 1.0; // Should not be forwarded.
      u8[15] = 0x40;
      u8[14] = 0x00;
      return f64[0];
    }

    main() {
      for (var i = 0; i < 20; i++) {
        Expect.equals(2.0, testViewAliasing1());
        Expect.equals(2.0, testViewAliasing2());
        Expect.equals(2.0, testViewAliasing3());
      }
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  const auto& function =
      Function::Handle(GetFunction(root_library, "testViewAliasing1"));

  Invoke(root_library, "main");

  TestPipeline pipeline(function, CompilerPass::kJIT);
  // Recent changes actually compile the function into a single basic
  // block, so we need to test right after the load optimizer has been run.
  // Have checked that this test still fails appropriately using the load
  // optimizer prior to the fix (commit 2a237327).
  FlowGraph* flow_graph = pipeline.RunPasses({
      CompilerPass::kComputeSSA,
      CompilerPass::kApplyICData,
      CompilerPass::kTryOptimizePatterns,
      CompilerPass::kSetOuterInliningId,
      CompilerPass::kTypePropagation,
      CompilerPass::kApplyClassIds,
      CompilerPass::kInlining,
      CompilerPass::kTypePropagation,
      CompilerPass::kApplyClassIds,
      CompilerPass::kTypePropagation,
      CompilerPass::kApplyICData,
      CompilerPass::kCanonicalize,
      CompilerPass::kBranchSimplify,
      CompilerPass::kIfConvert,
      CompilerPass::kCanonicalize,
      CompilerPass::kConstantPropagation,
      CompilerPass::kOptimisticallySpecializeSmiPhis,
      CompilerPass::kTypePropagation,
      CompilerPass::kWidenSmiToInt32,
      CompilerPass::kSelectRepresentations,
      CompilerPass::kCSE,
  });

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  AllocateTypedDataInstr* alloc_typed_data = nullptr;
  StoreIndexedInstr* first_store = nullptr;
  StoreIndexedInstr* second_store = nullptr;
  LoadIndexedInstr* final_load = nullptr;
  BoxInstr* boxed_result = nullptr;

  ILMatcher cursor(flow_graph, entry);
  RELEASE_ASSERT(cursor.TryMatch(
      {
          {kMatchAndMoveAllocateTypedData, &alloc_typed_data},
          kMatchAndMoveBranchTrue,
          kMatchAndMoveBranchTrue,
          kMatchAndMoveBranchFalse,
          kMatchAndMoveBranchFalse,
          {kMatchAndMoveStoreIndexed, &first_store},
          kMatchAndMoveBranchFalse,
          {kMatchAndMoveStoreIndexed, &second_store},
          {kMatchAndMoveLoadIndexed, &final_load},
          {kMatchAndMoveBox, &boxed_result},
          kMatchReturn,
      },
      /*insert_before=*/kMoveGlob));

  EXPECT(first_store->array()->definition() == alloc_typed_data);
  EXPECT(second_store->array()->definition() == alloc_typed_data);
  EXPECT(boxed_result->value()->definition() == final_load);
}

static void CountLoadsStores(FlowGraph* flow_graph,
                             intptr_t* loads,
                             intptr_t* stores) {
  for (BlockIterator block_it = flow_graph->reverse_postorder_iterator();
       !block_it.Done(); block_it.Advance()) {
    for (ForwardInstructionIterator it(block_it.Current()); !it.Done();
         it.Advance()) {
      if (it.Current()->IsLoadField()) {
        (*loads)++;
      } else if (it.Current()->IsStoreInstanceField()) {
        (*stores)++;
      }
    }
  }
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedundantStoresAndLoads) {
  const char* kScript = R"(
    class Bar {
      Bar() { a = null; }
      dynamic a;
    }

    Bar foo() {
      Bar bar = new Bar();
      bar.a = null;
      bar.a = bar;
      bar.a = bar.a;
      return bar.a;
    }

    main() {
      foo();
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  Invoke(root_library, "main");
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({
      CompilerPass::kComputeSSA,
      CompilerPass::kTypePropagation,
      CompilerPass::kApplyICData,
      CompilerPass::kInlining,
      CompilerPass::kTypePropagation,
      CompilerPass::kSelectRepresentations,
      CompilerPass::kCanonicalize,
      CompilerPass::kConstantPropagation,
  });

  ASSERT(flow_graph != nullptr);

  // Before CSE, we have 2 loads and 4 stores.
  intptr_t bef_loads = 0;
  intptr_t bef_stores = 0;
  CountLoadsStores(flow_graph, &bef_loads, &bef_stores);
  EXPECT_EQ(2, bef_loads);
  EXPECT_EQ(4, bef_stores);

  DominatorBasedCSE::Optimize(flow_graph);

  // After CSE, no load and only one store remains.
  intptr_t aft_loads = 0;
  intptr_t aft_stores = 0;
  CountLoadsStores(flow_graph, &aft_loads, &aft_stores);
  EXPECT_EQ(0, aft_loads);
  EXPECT_EQ(1, aft_stores);
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedundantStaticFieldInitialization) {
  const char* kScript = R"(
    int getX() => 2;
    int x = getX();

    foo() => x + x;

    main() {
      foo();
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  Invoke(root_library, "main");
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  ASSERT(flow_graph != nullptr);

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  ILMatcher cursor(flow_graph, entry);
  RELEASE_ASSERT(cursor.TryMatch({
      kMatchAndMoveFunctionEntry,
      kMatchAndMoveCheckStackOverflow,
      kMatchAndMoveLoadStaticField,
      kMoveParallelMoves,
      kMatchAndMoveCheckSmi,
      kMoveParallelMoves,
      kMatchAndMoveBinarySmiOp,
      kMoveParallelMoves,
      kMatchReturn,
  }));
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedundantInitializerCallAfterIf) {
  const char* kScript = R"(
    int x = int.parse('1');

    @pragma('vm:never-inline')
    use(int arg) {}

    foo(bool condition) {
      if (condition) {
        x = 3;
      } else {
        use(x);
      }
      use(x);
    }

    main() {
      foo(true);
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  Invoke(root_library, "main");
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  ASSERT(flow_graph != nullptr);

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  LoadStaticFieldInstr* load_static_after_if = nullptr;

  ILMatcher cursor(flow_graph, entry);
  RELEASE_ASSERT(cursor.TryMatch({
      kMoveGlob,
      kMatchAndMoveBranchTrue,
      kMoveGlob,
      kMatchAndMoveGoto,
      kMatchAndMoveJoinEntry,
      kMoveParallelMoves,
      {kMatchAndMoveLoadStaticField, &load_static_after_if},
      kMoveGlob,
      kMatchReturn,
  }));
  EXPECT(!load_static_after_if->calls_initializer());
}

ISOLATE_UNIT_TEST_CASE(LoadOptimizer_RedundantInitializerCallInLoop) {
  if (!TestCase::IsNNBD()) {
    return;
  }

  const char* kScript = R"(
    class A {
      late int x = int.parse('1');
      A? next;
    }

    @pragma('vm:never-inline')
    use(int arg) {}

    foo(A obj) {
      use(obj.x);
      for (;;) {
        use(obj.x);
        final next = obj.next;
        if (next == null) {
          break;
        }
        obj = next;
        use(obj.x);
      }
    }

    main() {
      foo(A()..next = A());
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  Invoke(root_library, "main");
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  ASSERT(flow_graph != nullptr);

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  LoadFieldInstr* load_field_before_loop = nullptr;
  LoadFieldInstr* load_field_in_loop1 = nullptr;
  LoadFieldInstr* load_field_in_loop2 = nullptr;

  ILMatcher cursor(flow_graph, entry);
  RELEASE_ASSERT(cursor.TryMatch({
      kMoveGlob,
      {kMatchAndMoveLoadField, &load_field_before_loop},
      kMoveGlob,
      kMatchAndMoveGoto,
      kMatchAndMoveJoinEntry,
      kMoveGlob,
      {kMatchAndMoveLoadField, &load_field_in_loop1},
      kMoveGlob,
      kMatchAndMoveBranchFalse,
      kMoveGlob,
      {kMatchAndMoveLoadField, &load_field_in_loop2},
  }));

  EXPECT(load_field_before_loop->calls_initializer());
  EXPECT(!load_field_in_loop1->calls_initializer());
  EXPECT(load_field_in_loop2->calls_initializer());
}

ISOLATE_UNIT_TEST_CASE(AllocationSinking_Arrays) {
  const char* kScript = R"(
import 'dart:typed_data';

class Vector2 {
  final Float64List _v2storage;

  @pragma('vm:prefer-inline')
  Vector2.zero() : _v2storage = Float64List(2);

  @pragma('vm:prefer-inline')
  factory Vector2(double x, double y) => Vector2.zero()..setValues(x, y);

  @pragma('vm:prefer-inline')
  factory Vector2.copy(Vector2 other) => Vector2.zero()..setFrom(other);

  @pragma('vm:prefer-inline')
  Vector2 clone() => Vector2.copy(this);

  @pragma('vm:prefer-inline')
  void setValues(double x_, double y_) {
    _v2storage[0] = x_;
    _v2storage[1] = y_;
  }

  @pragma('vm:prefer-inline')
  void setFrom(Vector2 other) {
    final otherStorage = other._v2storage;
    _v2storage[1] = otherStorage[1];
    _v2storage[0] = otherStorage[0];
  }

  @pragma('vm:prefer-inline')
  Vector2 operator +(Vector2 other) => clone()..add(other);

  @pragma('vm:prefer-inline')
  void add(Vector2 arg) {
    final argStorage = arg._v2storage;
    _v2storage[0] = _v2storage[0] + argStorage[0];
    _v2storage[1] = _v2storage[1] + argStorage[1];
  }

  @pragma('vm:prefer-inline')
  double get x => _v2storage[0];

  @pragma('vm:prefer-inline')
  double get y => _v2storage[1];
}

@pragma('vm:never-inline')
String foo(double x) {
  // All allocations in this function are eliminated by the compiler,
  // except array allocation for string interpolation at the end.
  List v1 = List.filled(2, null);
  v1[0] = 1;
  v1[1] = 'hi';
  Vector2 v2 = new Vector2(1.0, 2.0);
  Vector2 v3 = v2 + Vector2(x, x);
  double sum = v3.x + v3.y;
  return "v1: [${v1[0]},${v1[1]}], v2: [${v2.x},${v2.y}], v3: [${v3.x},${v3.y}], sum: $sum";
}

main() {
  foo(42.0);
}
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  Invoke(root_library, "main");
  const auto& function = Function::Handle(GetFunction(root_library, "foo"));
  TestPipeline pipeline(function, CompilerPass::kJIT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  ASSERT(flow_graph != nullptr);

  auto entry = flow_graph->graph_entry()->normal_entry();
  EXPECT(entry != nullptr);

  /* Flow graph to match:

  4:     CheckStackOverflow:8(stack=0, loop=0)
  5:     ParallelMove rax <- S+2
  6:     CheckClass:14(v2 Cids[1: _Double@0150898 etc.  cid 52])
  8:     v526 <- Unbox:14(v2 T{_Double}) T{_Double}
 10:     ParallelMove xmm1 <- C
 10:     v352 <- BinaryDoubleOp:22(+, v590, v526) T{_Double}
 11:     ParallelMove DS-6 <- xmm1
 12:     ParallelMove xmm2 <- C
 12:     v363 <- BinaryDoubleOp:34(+, v591, v526) T{_Double}
 13:     ParallelMove DS-5 <- xmm2
 14:     ParallelMove xmm0 <- xmm1
 14:     v21 <- BinaryDoubleOp:28(+, v352, v363) T{_Double}
 15:     ParallelMove rbx <- C, r10 <- C, DS-4 <- xmm0
 16:     v24 <- CreateArray:30(v0, v23) T{_List}
 17:     ParallelMove rcx <- rax
 18:     ParallelMove S-3 <- rcx
 18:     StoreIndexed(v24, v6, v26, NoStoreBarrier)
 20:     StoreIndexed(v24, v7, v7, NoStoreBarrier)
 22:     StoreIndexed(v24, v3, v29, NoStoreBarrier)
 24:     StoreIndexed(v24, v30, v8, NoStoreBarrier)
 26:     StoreIndexed(v24, v33, v34, NoStoreBarrier)
 28:     StoreIndexed(v24, v35, v9, NoStoreBarrier)
 30:     StoreIndexed(v24, v38, v29, NoStoreBarrier)
 32:     StoreIndexed(v24, v39, v10, NoStoreBarrier)
 34:     StoreIndexed(v24, v42, v43, NoStoreBarrier)
 35:     ParallelMove xmm0 <- DS-6
 36:     v586 <- Box(v352) T{_Double}
 37:     ParallelMove rdx <- rcx, rax <- rax
 38:     StoreIndexed(v24, v44, v586)
 40:     StoreIndexed(v24, v47, v29, NoStoreBarrier)
 41:     ParallelMove xmm0 <- DS-5
 42:     v588 <- Box(v363) T{_Double}
 43:     ParallelMove rdx <- rcx, rax <- rax
 44:     StoreIndexed(v24, v48, v588)
 46:     StoreIndexed(v24, v51, v52, NoStoreBarrier)
 47:     ParallelMove xmm0 <- DS-4
 48:     v580 <- Box(v21) T{_Double}
 49:     ParallelMove rdx <- rcx, rax <- rax
 50:     StoreIndexed(v24, v53, v580)
 51:     ParallelMove rax <- rcx
         PushArgument(v24)
 52:     v54 <- StaticCall:44(_StringBase._interpolate, v24) T{String}
 53:     ParallelMove rax <- rax
 54:     Return:48(v54)
*/

  CreateArrayInstr* create_array = nullptr;
  StaticCallInstr* string_interpolate = nullptr;

  ILMatcher cursor(flow_graph, entry, /*trace=*/true,
                   ParallelMovesHandling::kSkip);
  RELEASE_ASSERT(cursor.TryMatch({
      kMatchAndMoveFunctionEntry,
      kMatchAndMoveCheckStackOverflow,
      kMatchAndMoveCheckClass,
      kMatchAndMoveUnbox,
      kMatchAndMoveBinaryDoubleOp,
      kMatchAndMoveBinaryDoubleOp,
      kMatchAndMoveBinaryDoubleOp,
      {kMatchAndMoveCreateArray, &create_array},
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveBox,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveBox,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveStoreIndexed,
      kMatchAndMoveBox,
      kMatchAndMoveStoreIndexed,
      kMatchAndMovePushArgument,
      {kMatchAndMoveStaticCall, &string_interpolate},
      kMatchReturn,
  }));

  EXPECT(string_interpolate->ArgumentAt(0) == create_array);
}

#if !defined(TARGET_ARCH_IA32)

ISOLATE_UNIT_TEST_CASE(DelayAllocations_DelayAcrossCalls) {
  const char* kScript = R"(
    class A {
      dynamic x, y;
      A(this.x, this.y);
    }

    int count = 0;

    @pragma("vm:never-inline")
    dynamic foo(int i) => count++ < 2 ? i : '$i';

    @pragma("vm:never-inline")
    dynamic use(v) {}

    void test() {
      A a = new A(foo(1), foo(2));
      use(a);
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  const auto& function = Function::Handle(GetFunction(root_library, "test"));

  // Get fields to kDynamicCid guard
  Invoke(root_library, "test");
  Invoke(root_library, "test");

  TestPipeline pipeline(function, CompilerPass::kAOT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  auto entry = flow_graph->graph_entry()->normal_entry();

  StaticCallInstr* call1;
  StaticCallInstr* call2;
  AllocateObjectInstr* allocate;
  StoreInstanceFieldInstr* store1;
  StoreInstanceFieldInstr* store2;

  ILMatcher cursor(flow_graph, entry, true, ParallelMovesHandling::kSkip);
  RELEASE_ASSERT(cursor.TryMatch({
      kMoveGlob,
      {kMatchAndMoveStaticCall, &call1},
      kMoveGlob,
      {kMatchAndMoveStaticCall, &call2},
      kMoveGlob,
      {kMatchAndMoveAllocateObject, &allocate},
      {kMatchAndMoveStoreInstanceField, &store1},
      {kMatchAndMoveStoreInstanceField, &store2},
  }));

  EXPECT(strcmp(call1->function().UserVisibleNameCString(), "foo") == 0);
  EXPECT(strcmp(call2->function().UserVisibleNameCString(), "foo") == 0);
  EXPECT(store1->instance()->definition() == allocate);
  EXPECT(!store1->ShouldEmitStoreBarrier());
  EXPECT(store2->instance()->definition() == allocate);
  EXPECT(!store2->ShouldEmitStoreBarrier());
}

ISOLATE_UNIT_TEST_CASE(DelayAllocations_DontDelayIntoLoop) {
  const char* kScript = R"(
    void test() {
      Object o = new Object();
      for (int i = 0; i < 10; i++) {
        use(o);
      }
    }

    @pragma('vm:never-inline')
    void use(Object o) {
      print(o.hashCode);
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  const auto& function = Function::Handle(GetFunction(root_library, "test"));

  TestPipeline pipeline(function, CompilerPass::kAOT);
  FlowGraph* flow_graph = pipeline.RunPasses({});
  auto entry = flow_graph->graph_entry()->normal_entry();

  AllocateObjectInstr* allocate;
  StaticCallInstr* call;

  ILMatcher cursor(flow_graph, entry, true, ParallelMovesHandling::kSkip);
  RELEASE_ASSERT(cursor.TryMatch({
      kMoveGlob,
      {kMatchAndMoveAllocateObject, &allocate},
      kMoveGlob,
      kMatchAndMoveBranchTrue,
      kMoveGlob,
      {kMatchAndMoveStaticCall, &call},
  }));

  EXPECT(strcmp(call->function().UserVisibleNameCString(), "use") == 0);
  EXPECT(call->Receiver()->definition() == allocate);
}

ISOLATE_UNIT_TEST_CASE(CheckStackOverflowElimination_NoInterruptsPragma) {
  const char* kScript = R"(
    @pragma('vm:unsafe:no-interrupts')
    void test() {
      for (int i = 0; i < 10; i++) {
      }
    }
  )";

  const auto& root_library = Library::Handle(LoadTestScript(kScript));
  const auto& function = Function::Handle(GetFunction(root_library, "test"));

  TestPipeline pipeline(function, CompilerPass::kAOT);
  auto flow_graph = pipeline.RunPasses({});
  for (auto block : flow_graph->postorder()) {
    for (auto instr : block->instructions()) {
      EXPECT_PROPERTY(instr, !it.IsCheckStackOverflow());
    }
  }
}

// This test checks that CSE unwraps redefinitions when comparing all
// instructions except loads, which are handled specially.
ISOLATE_UNIT_TEST_CASE(CSE_Redefinitions) {
  const char* script_chars = R"(
    @pragma("vm:external-name", "BlackholeNative")
    external dynamic blackhole([a, b, c, d, e, f]);
    class K<T> {
      final T field;
      K(this.field);
    }
  )";
  const Library& lib =
      Library::Handle(LoadTestScript(script_chars, NoopNativeLookup));

  const Class& cls = Class::ZoneHandle(
      lib.LookupLocalClass(String::Handle(Symbols::New(thread, "K"))));
  const Error& err = Error::Handle(cls.EnsureIsFinalized(thread));
  EXPECT(err.IsNull());

  const Field& original_field = Field::Handle(
      cls.LookupField(String::Handle(Symbols::New(thread, "field"))));
  EXPECT(!original_field.IsNull());
  const Field& field = Field::Handle(original_field.CloneFromOriginal());

  const Function& blackhole =
      Function::ZoneHandle(GetFunction(lib, "blackhole"));

  using compiler::BlockBuilder;
  CompilerState S(thread, /*is_aot=*/false, /*is_optimizing=*/true);
  FlowGraphBuilderHelper H;

  auto b1 = H.flow_graph()->graph_entry()->normal_entry();

  BoxInstr* box0;
  BoxInstr* box1;
  LoadFieldInstr* load0;
  LoadFieldInstr* load1;
  LoadFieldInstr* load2;
  StaticCallInstr* call;
  ReturnInstr* ret;

  {
    BlockBuilder builder(H.flow_graph(), b1);
    auto& slot = Slot::Get(field, &H.flow_graph()->parsed_function());
    auto param0 =
        builder.AddParameter(0, 0, /*with_frame=*/true, kUnboxedDouble);
    auto param1 = builder.AddParameter(1, 2, /*with_frame=*/true, kTagged);
    auto redef0 =
        builder.AddDefinition(new RedefinitionInstr(new Value(param0)));
    auto redef1 =
        builder.AddDefinition(new RedefinitionInstr(new Value(param0)));
    box0 = builder.AddDefinition(
        BoxInstr::Create(kUnboxedDouble, new Value(redef0)));
    box1 = builder.AddDefinition(
        BoxInstr::Create(kUnboxedDouble, new Value(redef1)));

    auto redef2 =
        builder.AddDefinition(new RedefinitionInstr(new Value(param1)));
    auto redef3 =
        builder.AddDefinition(new RedefinitionInstr(new Value(param1)));
    load0 = builder.AddDefinition(
        new LoadFieldInstr(new Value(redef2), slot, InstructionSource()));
    load1 = builder.AddDefinition(
        new LoadFieldInstr(new Value(redef3), slot, InstructionSource()));
    load2 = builder.AddDefinition(
        new LoadFieldInstr(new Value(redef3), slot, InstructionSource()));

    auto args = new InputsArray(3);
    args->Add(new Value(load0));
    args->Add(new Value(load1));
    args->Add(new Value(load2));
    call = builder.AddInstruction(new StaticCallInstr(
        InstructionSource(), blackhole, 0, Array::empty_array(), args,
        S.GetNextDeoptId(), 0, ICData::RebindRule::kStatic));

    ret = builder.AddReturn(new Value(box1));
  }
  H.FinishGraph();

  // Running CSE without load optimization should eliminate redundant boxing
  // but keep loads intact if they don't  have exactly matching inputs.
  DominatorBasedCSE::Optimize(H.flow_graph(), /*run_load_optimization=*/false);

  EXPECT_PROPERTY(box1, it.WasEliminated());
  EXPECT_PROPERTY(ret, it.value()->definition() == box0);

  EXPECT_PROPERTY(load0, !it.WasEliminated());
  EXPECT_PROPERTY(load1, !it.WasEliminated());
  EXPECT_PROPERTY(load2, it.WasEliminated());

  EXPECT_PROPERTY(call, it.ArgumentAt(0) == load0);
  EXPECT_PROPERTY(call, it.ArgumentAt(1) == load1);
  EXPECT_PROPERTY(call, it.ArgumentAt(2) == load1);

  // Running load optimization pass should remove the second load but
  // insert a redefinition to prevent code motion because the field
  // has a generic type.
  DominatorBasedCSE::Optimize(H.flow_graph(), /*run_load_optimization=*/true);

  EXPECT_PROPERTY(load0, !it.WasEliminated());
  EXPECT_PROPERTY(load1, it.WasEliminated());
  EXPECT_PROPERTY(load2, it.WasEliminated());

  EXPECT_PROPERTY(call, it.ArgumentAt(0) == load0);
  EXPECT_PROPERTY(call, it.ArgumentAt(1)->IsRedefinition() &&
                            it.ArgumentAt(1)->OriginalDefinition() == load0);
  EXPECT_PROPERTY(call, it.ArgumentAt(2)->IsRedefinition() &&
                            it.ArgumentAt(2)->OriginalDefinition() == load0);
}

#endif  // !defined(TARGET_ARCH_IA32)

}  // namespace dart