[turbofan] Extend LoadElimination to introduce TypeGuards.

test/unittests/compiler/load-elimination-unittest.cc

Index: test/unittests/compiler/load-elimination-unittest.cc
diff --git a/test/unittests/compiler/load-elimination-unittest.cc b/test/unittests/compiler/load-elimination-unittest.cc
index 1c5a8375015baae5d51f65067dfbd18a6c636e42..2306f72b4c32f1482a43f1373e11c678f43f943e 100644
--- a/test/unittests/compiler/load-elimination-unittest.cc
+++ b/test/unittests/compiler/load-elimination-unittest.cc
@@ -359,6 +359,64 @@ TEST_F(LoadEliminationTest, LoadFieldOnTrueBranchOfDiamond) {
   EXPECT_EQ(load, r.replacement());
 }
 
+TEST_F(LoadEliminationTest, LoadFieldWithTypeMismatch) {
+  Node* object = Parameter(Type::Any(), 0);
+  Node* value = Parameter(Type::Signed32(), 1);
+  Node* effect = graph()->start();
+  Node* control = graph()->start();
+  FieldAccess const access = {kTaggedBase,
+                              kPointerSize,
+                              MaybeHandle<Name>(),
+                              Type::Unsigned31(),
+                              MachineType::AnyTagged(),
+                              kNoWriteBarrier};
+
+  StrictMock<MockAdvancedReducerEditor> editor;
+  LoadElimination load_elimination(&editor, jsgraph(), zone());
+
+  load_elimination.Reduce(graph()->start());
+
+  Node* store = effect = graph()->NewNode(simplified()->StoreField(access),
+                                          object, value, effect, control);
+  load_elimination.Reduce(effect);
+
+  Node* load = graph()->NewNode(simplified()->LoadField(access), object, effect,
+                                control);
+  EXPECT_CALL(editor,
+              ReplaceWithValue(load, IsTypeGuard(value, control), store, _));
+  Reduction r = load_elimination.Reduce(load);
+  ASSERT_TRUE(r.Changed());
+  EXPECT_THAT(r.replacement(), IsTypeGuard(value, control));
+}
+
+TEST_F(LoadEliminationTest, LoadElementWithTypeMismatch) {
+  Node* object = Parameter(Type::Any(), 0);
+  Node* index = Parameter(Type::UnsignedSmall(), 1);
+  Node* value = Parameter(Type::Signed32(), 2);
+  Node* effect = graph()->start();
+  Node* control = graph()->start();
+  ElementAccess const access = {kTaggedBase, kPointerSize, Type::Unsigned31(),
+                                MachineType::AnyTagged(), kNoWriteBarrier};
+
+  StrictMock<MockAdvancedReducerEditor> editor;
+  LoadElimination load_elimination(&editor, jsgraph(), zone());
+
+  load_elimination.Reduce(graph()->start());
+
+  Node* store = effect =
+      graph()->NewNode(simplified()->StoreElement(access), object, index, value,
+                       effect, control);
+  load_elimination.Reduce(effect);
+
+  Node* load = graph()->NewNode(simplified()->LoadElement(access), object,
+                                index, effect, control);
+  EXPECT_CALL(editor,
+              ReplaceWithValue(load, IsTypeGuard(value, control), store, _));
+  Reduction r = load_elimination.Reduce(load);
+  ASSERT_TRUE(r.Changed());
+  EXPECT_THAT(r.replacement(), IsTypeGuard(value, control));
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8