[runtime] Avoid @@isConcatSpreadable lookup for fast path Array.prototype.concat

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

 // Copyright 2012 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/arm/lithium-codegen-arm.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/arm/lithium-gap-resolver-arm.h"
@@ skipping 2957 matching lines @@
       DeoptimizeIf(eq, instr, Deoptimizer::kHole);
     }
   } else if (instr->hydrogen()->hole_mode() == CONVERT_HOLE_TO_UNDEFINED) {
     DCHECK(instr->hydrogen()->elements_kind() == FAST_HOLEY_ELEMENTS);
     Label done;
     __ LoadRoot(scratch, Heap::kTheHoleValueRootIndex);
     __ cmp(result, scratch);
     __ b(ne, &done);
     if (info()->IsStub()) {
       // A stub can safely convert the hole to undefined only if the array
-      // protector cell contains (Smi) Isolate::kArrayProtectorValid. Otherwise
-      // it needs to bail out.
+      // protector cell contains (Smi) Isolate::kArrayProtectorValid.
+      // Otherwise it needs to bail out.

[Toon Verwaest, 2016/03/31 08:09:46]

Spurious change ... :)

       __ LoadRoot(result, Heap::kArrayProtectorRootIndex);
       __ ldr(result, FieldMemOperand(result, Cell::kValueOffset));
       __ cmp(result, Operand(Smi::FromInt(Isolate::kArrayProtectorValid)));
       DeoptimizeIf(ne, instr, Deoptimizer::kHole);
     }
     __ LoadRoot(result, Heap::kUndefinedValueRootIndex);
     __ bind(&done);
   }
 }
 
@@ skipping 2555 matching lines @@
 void LCodeGen::DoStoreFrameContext(LStoreFrameContext* instr) {
   Register context = ToRegister(instr->context());
   __ str(context, MemOperand(fp, StandardFrameConstants::kContextOffset));
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8