The IC exposes a register definition.

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 0bc57390ecedc08840e4f5d9e571ce799aca4435..6ace698393754fe4b106682c67d4a73d2eaf5abc 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -89,26 +89,6 @@ void CreateAllocationSiteStub::InitializeInterfaceDescriptor(
 }
 
 
-void KeyedLoadFastElementStub::InitializeInterfaceDescriptor(
-    CodeStubInterfaceDescriptor* descriptor) {
-  static Register registers[] = { rdx, rax };
-  descriptor->register_param_count_ = 2;
-  descriptor->register_params_ = registers;
-  descriptor->deoptimization_handler_ =
-      FUNCTION_ADDR(KeyedLoadIC_MissFromStubFailure);
-}
-
-
-void KeyedLoadDictionaryElementStub::InitializeInterfaceDescriptor(
-    CodeStubInterfaceDescriptor* descriptor) {
-  static Register registers[] = { rdx, rax };
-  descriptor->register_param_count_ = 2;
-  descriptor->register_params_ = registers;
-  descriptor->deoptimization_handler_ =
-    FUNCTION_ADDR(KeyedLoadIC_MissFromStubFailure);
-}
-
-
 void RegExpConstructResultStub::InitializeInterfaceDescriptor(
     CodeStubInterfaceDescriptor* descriptor) {
   static Register registers[] = { rcx, rbx, rax };
@@ -119,16 +99,6 @@ void RegExpConstructResultStub::InitializeInterfaceDescriptor(
 }
 
 
-void KeyedLoadGenericElementStub::InitializeInterfaceDescriptor(
-    CodeStubInterfaceDescriptor* descriptor) {
-  static Register registers[] = { rdx, rax };
-  descriptor->register_param_count_ = 2;
-  descriptor->register_params_ = registers;
-  descriptor->deoptimization_handler_ =
-      Runtime::FunctionForId(Runtime::kKeyedGetProperty)->entry;
-}
-
-
 void LoadFieldStub::InitializeInterfaceDescriptor(
     CodeStubInterfaceDescriptor* descriptor) {
   static Register registers[] = { rax };