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

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 201ecb26ff5ee483e56ed53bafd6094a89ba1abe..35e6a53066b2ea4e0dacddf90381861e115f8017 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2130,7 +2130,14 @@ void BinaryOpStub_GenerateSmiCode(
 
 
 void BinaryOpStub::GenerateSmiStub(MacroAssembler* masm) {
-  Label not_smis, 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(r0, Operand(Smi::FromInt(fixed_right_arg_value())));
+    __ b(ne, &right_arg_changed);
+  }
 
   if (result_type_ == BinaryOpIC::UNINITIALIZED ||
       result_type_ == BinaryOpIC::SMI) {
@@ -2147,6 +2154,7 @@ 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);
 
   __ bind(&call_runtime);
@@ -2318,6 +2326,9 @@ void BinaryOpStub::GenerateInt32Stub(MacroAssembler* masm) {
         // to type transition.
 
       } else {
+        // TODO(svenpanne) We should check the right argument here, see the
+        // beginning of GenerateSmiStub, but I can't figure out how... :-/
+
         // We preserved r0 and r1 to be able to call runtime.
         // Save the left value on the stack.
         __ Push(r5, r4);