[TurboFan] Broken effect chain in IsInstanceType reduction

We didn't correctly maintain the effect chain between the load of
the map and the load of the instance type from the map.

Bug: v8:6929
Change-Id: I970709fe74483c5cdef3d0cea36bb9e1dc98b40e
Reviewed-on: https://chromium-review.googlesource.com/725424Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48690}

src/compiler/js-intrinsic-lowering.cc

@@ -239,12 +239,15 @@ Reduction JSIntrinsicLowering::ReduceIsInstanceType(
   Node* vtrue = jsgraph()->FalseConstant();
 
   Node* if_false = graph()->NewNode(common()->IfFalse(), branch);
-  Node* efalse = graph()->NewNode(
-      simplified()->LoadField(AccessBuilder::ForMapInstanceType()),
+  Node* efalse = effect;
+  Node* map = efalse =
       graph()->NewNode(simplified()->LoadField(AccessBuilder::ForMap()), value,
-                       effect, if_false),
-      effect, if_false);
-  Node* vfalse = graph()->NewNode(simplified()->NumberEqual(), efalse,
+                       efalse, if_false);
+  Node* map_instance_type = efalse = graph()->NewNode(
+      simplified()->LoadField(AccessBuilder::ForMapInstanceType()), map, efalse,
+      if_false);
+  Node* vfalse =
+      graph()->NewNode(simplified()->NumberEqual(), map_instance_type,
                        jsgraph()->Constant(instance_type));
 
   Node* merge = graph()->NewNode(common()->Merge(2), if_true, if_false);

test/unittests/compiler/js-intrinsic-lowering-unittest.cc

@@ -88,7 +88,7 @@ TEST_F(JSIntrinsicLoweringTest, InlineIsArray) {
           IsNumberEqual(IsLoadField(AccessBuilder::ForMapInstanceType(),
                                     IsLoadField(AccessBuilder::ForMap(), input,
                                                 effect, CaptureEq(&if_false)),
-                                    effect, _),
+                                    _, _),
                         IsNumberConstant(JS_ARRAY_TYPE)),
           IsMerge(IsIfTrue(AllOf(CaptureEq(&branch),
                                  IsBranch(IsObjectIsSmi(input), control))),
@@ -119,7 +119,7 @@ TEST_F(JSIntrinsicLoweringTest, InlineIsTypedArray) {
           IsNumberEqual(IsLoadField(AccessBuilder::ForMapInstanceType(),
                                     IsLoadField(AccessBuilder::ForMap(), input,
                                                 effect, CaptureEq(&if_false)),
-                                    effect, _),
+                                    _, _),
                         IsNumberConstant(JS_TYPED_ARRAY_TYPE)),
           IsMerge(IsIfTrue(AllOf(CaptureEq(&branch),
                                  IsBranch(IsObjectIsSmi(input), control))),