deps: update V8 to 5.1.281.69

Pick up the latest branch-head for V8 5.1. This branch brings in
improved language support and performance improvements. For full
details: http://v8project.blogspot.com/2016/04/v8-release-51.html

* Picks up the latest branch head for 5.1 [1]
* Edit v8 gitignore to allow trace_event copy
* Update V8 DEP trace_event as per deps/v8/DEPS [2]

[1] https://chromium.googlesource.com/v8/v8.git/+/dc81244
[2] https://chromium.googlesource.com/chromium/src/base/trace_event/common/+/c8c8665

PR-URL: https://github.com/nodejs/node/pull/7016
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

1 files changed, 13 insertions, 3 deletions

diff --git a/deps/v8/src/compiler/simplified-operator-reducer.cc b/deps/v8/src/compiler/simplified-operator-reducer.cc
index 120d7926d5..012004a8af 100644
--- a/deps/v8/src/compiler/simplified-operator-reducer.cc
+++ b/deps/v8/src/compiler/simplified-operator-reducer.cc
@@ -9,14 +9,14 @@
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/operator-properties.h"
 #include "src/conversions-inl.h"
+#include "src/type-cache.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 SimplifiedOperatorReducer::SimplifiedOperatorReducer(JSGraph* jsgraph)
-    : jsgraph_(jsgraph) {}
-
+    : jsgraph_(jsgraph), type_cache_(TypeCache::Get()) {}
 
 SimplifiedOperatorReducer::~SimplifiedOperatorReducer() {}
 
@@ -89,6 +89,17 @@ Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
       if (m.HasValue()) return ReplaceNumber(FastUI2D(m.Value()));
       break;
     }
+    case IrOpcode::kNumberCeil:
+    case IrOpcode::kNumberFloor:
+    case IrOpcode::kNumberRound:
+    case IrOpcode::kNumberTrunc: {
+      Node* const input = NodeProperties::GetValueInput(node, 0);
+      Type* const input_type = NodeProperties::GetType(input);
+      if (input_type->Is(type_cache_.kIntegerOrMinusZeroOrNaN)) {
+        return Replace(input);
+      }
+      break;
+    }
     case IrOpcode::kReferenceEqual:
       return ReduceReferenceEqual(node);
     default:
@@ -97,7 +108,6 @@ Reduction SimplifiedOperatorReducer::Reduce(Node* node) {
   return NoChange();
 }
 
-
 Reduction SimplifiedOperatorReducer::ReduceReferenceEqual(Node* node) {
   DCHECK_EQ(IrOpcode::kReferenceEqual, node->opcode());
   Node* const left = NodeProperties::GetValueInput(node, 0);