Collect type feedback on result of Math.[round|ceil|floor]

src/type-info.cc

Index: src/type-info.cc
diff --git a/src/type-info.cc b/src/type-info.cc
index 4ad66f85573e78786bb0716be81550146bdd627a..587d4ade0a3eaa36105321efcae26b8228bbfcf3 100644
--- a/src/type-info.cc
+++ b/src/type-info.cc
@@ -142,6 +142,23 @@ bool TypeFeedbackOracle::CallIsMonomorphic(FeedbackVectorICSlot slot) {
 }
 
 
+bool TypeFeedbackOracle::CallIsBuiltinWithMinusZeroResult(
+    FeedbackVectorICSlot slot) {
+  Handle<Object> value = GetInfo(slot);
+  if (!value->IsJSFunction()) return false;
+  Handle<JSFunction> maybe_round(Handle<JSFunction>::cast(value));
+  SmartArrayPointer<char> n = maybe_round->shared()->DebugName()->ToCString();

[mvstanton, 2015/05/04 09:41:22]

You don't need n here.

[danno, 2015/05/04 14:31:56]

Done.

+  if (!maybe_round->shared()->HasBuiltinFunctionId()) return false;
+  if (maybe_round->shared()->builtin_function_id() != kMathRound &&
+      maybe_round->shared()->builtin_function_id() != kMathFloor &&
+      maybe_round->shared()->builtin_function_id() != kMathCeil) {
+    return false;
+  }
+  return feedback_vector_->get(feedback_vector_->GetIndex(slot) + 1) ==
+         Smi::FromInt(CallICStub::kHasReturnedMinusZeroSentinel);
+}
+
+
 bool TypeFeedbackOracle::CallNewIsMonomorphic(FeedbackVectorSlot slot) {
   Handle<Object> info = GetInfo(slot);
   return FLAG_pretenuring_call_new