[turbofan] fixed escape analysis bug: missing copy of virtual state

R=jarin@chromium.org

BUG=chromium:673243

Review-Url: https://codereview.chromium.org/2578133002
Cr-Commit-Position: refs/heads/master@{#41848}

src/compiler/escape-analysis.cc

@@ -1083,6 +1083,9 @@ bool EscapeAnalysis::Process(Node* node) {
       ProcessAllocationUsers(node);
       break;
   }
+  if (OperatorProperties::HasFrameStateInput(node->op())) {
+    virtual_states_[node->id()]->SetCopyRequired();
+  }
   return true;
 }
 
@@ -1176,8 +1179,7 @@ void EscapeAnalysis::ForwardVirtualState(Node* node) {
           static_cast<void*>(virtual_states_[effect->id()]),
           effect->op()->mnemonic(), effect->id(), node->op()->mnemonic(),
           node->id());
-    if (status_analysis_->IsEffectBranchPoint(effect) ||
-        OperatorProperties::HasFrameStateInput(node->op())) {
+    if (status_analysis_->IsEffectBranchPoint(effect)) {
       virtual_states_[node->id()]->SetCopyRequired();
       TRACE(", effect input %s#%d is branch point", effect->op()->mnemonic(),
             effect->id());

test/mjsunit/compiler/escape-analysis-framestate-use-at-branchpoint.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax --turbo --turbo-escape
+
+function foo() {
+  var o = {x:0};
+  for (var i = 0; o.x < 1;) {
+    o.x++;
+    i+= 1;
+  }
+ function bar() {i};
+ return o.x;
+}
+foo();
+foo();
+%OptimizeFunctionOnNextCall(foo);
+foo();