Simplify stack check instruction in Crankshaft.

src/x64/lithium-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2185 matching lines @@
         set_deoptimization_environment(result->environment());
     ClearInstructionPendingDeoptimizationEnvironment();
     return result;
   }
 
   return NULL;
 }
 
 
 LInstruction* LChunkBuilder::DoStackCheck(HStackCheck* instr) {
-  if (instr->is_function_entry()) {
-    return MarkAsCall(new LStackCheck, instr);
-  } else {
-    ASSERT(instr->is_backwards_branch());
-    return AssignEnvironment(AssignPointerMap(new LStackCheck));
-  }
+  return AssignEnvironment(AssignPointerMap(new LStackCheck));
 }
 
 
 LInstruction* LChunkBuilder::DoEnterInlined(HEnterInlined* instr) {
   HEnvironment* outer = current_block_->last_environment();
   HConstant* undefined = graph()->GetConstantUndefined();
   HEnvironment* inner = outer->CopyForInlining(instr->closure(),
                                                instr->function(),
                                                undefined,
                                                instr->call_kind());
@@ skipping 14 matching lines @@
   LOperand* key = UseOrConstantAtStart(instr->key());
   LOperand* object = UseOrConstantAtStart(instr->object());
   LIn* result = new LIn(key, object);
   return MarkAsCall(DefineFixed(result, rax), instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64