Use NeedsContext() instead of comparing num_heap_slots().

src/crankshaft/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/crankshaft/x64/lithium-codegen-x64.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 149 matching lines @@
     }
   }
   return !is_aborted();
 }
 
 
 void LCodeGen::DoPrologue(LPrologue* instr) {
   Comment(";;; Prologue begin");
 
   // Possibly allocate a local context.
-  if (info_->scope()->num_heap_slots() > 0) {
+  if (info_->scope()->NeedsContext()) {
     Comment(";;; Allocate local context");
     bool need_write_barrier = true;
     // Argument to NewContext is the function, which is still in rdi.
     int slots = info_->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     Safepoint::DeoptMode deopt_mode = Safepoint::kNoLazyDeopt;
     if (info()->scope()->is_script_scope()) {
       __ Push(rdi);
       __ Push(info()->scope()->GetScopeInfo(info()->isolate()));
       __ CallRuntime(Runtime::kNewScriptContext);
       deopt_mode = Safepoint::kLazyDeopt;
@@ skipping 5383 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64