Collect type feedback for power-of-2 right operands in BinaryOps.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index e9f7e4689be0455ddc5e8b5c85a36ba9ae62bd05..8239e0e40365562e0a29b205d6a2262b270bad52 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -1317,7 +1317,15 @@ void BinaryOpStub::GenerateAddStrings(MacroAssembler* masm) {
 
 
 void BinaryOpStub::GenerateSmiStub(MacroAssembler* masm) {
-  Label call_runtime;
+  Label right_arg_changed, call_runtime;
+
+  if (op_ == Token::MOD && has_fixed_right_arg_) {
+    // It is guaranteed that the value will fit into a Smi, because if it
+    // didn't, we wouldn't be here, see BinaryOp_Patch.
+    __ Cmp(rax, Smi::FromInt(fixed_right_arg_value()));
+    __ j(not_equal, &right_arg_changed);
+  }
+
   if (result_type_ == BinaryOpIC::UNINITIALIZED ||
       result_type_ == BinaryOpIC::SMI) {
     // Only allow smi results.
@@ -1331,6 +1339,7 @@ void BinaryOpStub::GenerateSmiStub(MacroAssembler* masm) {
 
   // Code falls through if the result is not returned as either a smi or heap
   // number.
+  __ bind(&right_arg_changed);
   GenerateTypeTransition(masm);
 
   if (call_runtime.is_linked()) {