[crankshaft] Remove the useless HAllocateBlockContext instruction.

src/crankshaft/hydrogen.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.
 
 #include "src/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 4717 matching lines @@
         if (declaration_scope->is_script_scope() ||
             declaration_scope->is_eval_scope()) {
           function = new (zone())
               HLoadContextSlot(outer_context, Context::CLOSURE_INDEX,
                                HLoadContextSlot::kNoCheck);
         } else {
           function = New<HThisFunction>();
         }
         AddInstruction(function);
         // Allocate a block context and store it to the stack frame.
-        HInstruction* inner_context = Add<HAllocateBlockContext>(
-            outer_context, function, scope->GetScopeInfo(isolate()));
+        HValue* scope_info = Add<HConstant>(scope->GetScopeInfo(isolate()));
+        Add<HPushArguments>(scope_info, function);
+        HInstruction* inner_context = Add<HCallRuntime>(
+            Runtime::FunctionForId(Runtime::kPushBlockContext), 2);
+        inner_context->SetFlag(HValue::kHasNoObservableSideEffects);
         HInstruction* instr = Add<HStoreFrameContext>(inner_context);
         set_scope(scope);
         environment()->BindContext(inner_context);
         if (instr->HasObservableSideEffects()) {
           AddSimulate(stmt->EntryId(), REMOVABLE_SIMULATE);
         }
       }
       VisitDeclarations(scope->declarations());
       AddSimulate(stmt->DeclsId(), REMOVABLE_SIMULATE);
     }
@@ skipping 8806 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8