Simplify invocation sequence at monomorphic function invocation sites.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index c4f12f0a7c387a7fe858bb58e90a70391aefe9e2..2caae0dd8b9c07f67e631e2ad0f5014f4a2fe907 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -2693,7 +2693,8 @@ void LCodeGen::DoGlobalReceiver(LGlobalReceiver* instr) {
 void LCodeGen::CallKnownFunction(Handle<JSFunction> function,
                                  int arity,
                                  LInstruction* instr,
-                                 CallKind call_kind) {
+                                 CallKind call_kind,
+                                 RDIState rdi_state) {
   bool can_invoke_directly = !function->NeedsArgumentsAdaption() ||
       function->shared()->formal_parameter_count() == arity;
 
@@ -2701,7 +2702,9 @@ void LCodeGen::CallKnownFunction(Handle<JSFunction> function,
   RecordPosition(pointers->position());
 
   if (can_invoke_directly) {
-    __ LoadHeapObject(rdi, function);
+    if (rdi_state == RDI_UNINITIALIZED) {
+      __ LoadHeapObject(rdi, function);
+    }
 
     // Change context if needed.
     bool change_context =
@@ -2746,7 +2749,8 @@ void LCodeGen::DoCallConstantFunction(LCallConstantFunction* instr) {
   CallKnownFunction(instr->function(),
                     instr->arity(),
                     instr,
-                    CALL_AS_METHOD);
+                    CALL_AS_METHOD,
+                    RDI_UNINITIALIZED);
 }
 
 
@@ -3184,12 +3188,21 @@ void LCodeGen::DoInvokeFunction(LInvokeFunction* instr) {
   ASSERT(ToRegister(instr->function()).is(rdi));
   ASSERT(instr->HasPointerMap());
   ASSERT(instr->HasDeoptimizationEnvironment());
-  LPointerMap* pointers = instr->pointer_map();
-  RecordPosition(pointers->position());
-  SafepointGenerator generator(this, pointers, Safepoint::kLazyDeopt);
-  ParameterCount count(instr->arity());
-  __ InvokeFunction(rdi, count, CALL_FUNCTION, generator, CALL_AS_METHOD);
-  __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
+
+  if (instr->known_function().is_null()) {
+    LPointerMap* pointers = instr->pointer_map();
+    RecordPosition(pointers->position());
+    SafepointGenerator generator(this, pointers, Safepoint::kLazyDeopt);
+    ParameterCount count(instr->arity());
+    __ InvokeFunction(rdi, count, CALL_FUNCTION, generator, CALL_AS_METHOD);
+    __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
+  } else {
+    CallKnownFunction(instr->known_function(),
+                      instr->arity(),
+                      instr,
+                      CALL_AS_METHOD,
+                      RDI_CONTAINS_TARGET);
+  }
 }
 
 
@@ -3243,7 +3256,11 @@ void LCodeGen::DoCallGlobal(LCallGlobal* instr) {
 
 void LCodeGen::DoCallKnownGlobal(LCallKnownGlobal* instr) {
   ASSERT(ToRegister(instr->result()).is(rax));
-  CallKnownFunction(instr->target(), instr->arity(), instr, CALL_AS_FUNCTION);
+  CallKnownFunction(instr->target(),
+                    instr->arity(),
+                    instr,
+                    CALL_AS_FUNCTION,
+                    RDI_UNINITIALIZED);
 }