The IC exposes a register definition.

src/x87/ic-x87.cc

Index: src/x87/ic-x87.cc
diff --git a/src/x87/ic-x87.cc b/src/x87/ic-x87.cc
index 6cd9ac4e68312fa8002f2a548361d0c04b11232d..4bda4d747b75624add854900d1de26f4a101a4bd 100644
--- a/src/x87/ic-x87.cc
+++ b/src/x87/ic-x87.cc
@@ -1025,6 +1025,27 @@ void KeyedLoadIC::GenerateMiss(MacroAssembler* masm) {
 }
 
 
+// IC register specifications
+const Register LoadIC::ReceiverRegister() { return edx; }
+const Register LoadIC::NameRegister() { return ecx; }
+
+
+const Register KeyedLoadIC::ReceiverRegister() {
+  return LoadIC::ReceiverRegister();
+}
+
+
+const Register KeyedLoadIC::NameRegister() { return LoadIC::NameRegister(); }
+
+
+const Register* KeyedLoadIC::AllocateRegisterArray() {
+  Register* registers = new Register[kRegisterArgumentCount];
+  registers[0] = ReceiverRegister();
+  registers[1] = NameRegister();
+  return registers;
+}
+
+
 void KeyedLoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- ecx    : key