[Interpreter] Collect type feedback for subtract operation and pass it to turbofan.

src/compiler/bytecode-graph-builder.cc

Index: src/compiler/bytecode-graph-builder.cc
diff --git a/src/compiler/bytecode-graph-builder.cc b/src/compiler/bytecode-graph-builder.cc
index 621ca104d880ab2ecdb43bddb3f194e5815c2d5e..a02a41e29832618a874facb2239aabd6f0f5fb53 100644
--- a/src/compiler/bytecode-graph-builder.cc
+++ b/src/compiler/bytecode-graph-builder.cc
@@ -1141,7 +1141,17 @@ void BytecodeGraphBuilder::VisitAdd() {
 }
 
 void BytecodeGraphBuilder::VisitSub() {
-  BinaryOperationHints hints = BinaryOperationHints::Any();
+  // TODO(mythria): Move this to a helper function, once more binary operations
+  // record type feedback.

[rmcilroy, 2016/08/08 08:27:31]

Could you just do this now so that it's reused when we add more?

[mythria, 2016/08/09 00:51:59]

Done.

+  FeedbackVectorSlot slot =
+      feedback_vector()->ToSlot(bytecode_iterator().GetIndexOperand(1));
+  DCHECK_EQ(FeedbackVectorSlotKind::GENERAL, feedback_vector()->GetKind(slot));
+  Object* feedback = feedback_vector()->Get(slot);
+  BinaryOperationHints::Hint hint = BinaryOperationHints::Hint::kAny;
+  if (feedback->IsSmi()) {
+    hint = BinaryOperationHintFromFeedback((Smi::cast(feedback))->value());
+  }
+  BinaryOperationHints hints(hint, hint, hint);
   BuildBinaryOp(javascript()->Subtract(hints));
 }