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 20d4da5e7f64d08c1e7812839d51b36e00c87bbc..08f5c86c28b143fde0e219683572a8210df3ebff 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -2029,7 +2029,14 @@ 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) {
@@ -2046,6 +2053,7 @@ 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);
@@ -2217,6 +2225,12 @@ void BinaryOpStub::GenerateInt32Stub(MacroAssembler* masm) {
         // to type transition.
 
       } else {
+        if (has_fixed_right_arg_) {
+          __ Vmov(d8, fixed_right_arg_value(), scratch1);
+          __ VFPCompareAndSetFlags(d1, d8);

[Rodolph Perfetta, 2013/06/03 16:33:17]

Wouldn't it be possible to compare to the already converted int32:

  __ cmp(right, Operand(fixed_right_arg_value());

[Sven Panne, 2013/06/04 07:48:09]

Hmmm, unless I misunderstood things, 'right' doesn't contain the int32 value at
that point, it still contains the right operand, which could be a Smi or a
HeapNumber. On Intel things are different, the conversion macro instructions set
both floating register *and* a normal one. Because this doesn't appear to be the
case here, I did it the other way round (int=>double, then compare the double).

Nevertheless, if you see some way to improve this, I'll be happy to review the
change.

+          __ b(ne, &transition);
+        }
+
         // We preserved r0 and r1 to be able to call runtime.
         // Save the left value on the stack.
         __ Push(r5, r4);