With flag optimize-constructed-arrays on, ARM and MIPS suffered a performance degrade

src/arm/code-stubs-arm.cc

 // Copyright 2012 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 4772 matching lines @@
 
   // A monomorphic miss (i.e, here the cache is not uninitialized) goes
   // megamorphic.
   __ CompareRoot(r3, Heap::kTheHoleValueRootIndex);
   __ b(eq, &initialize);
   // MegamorphicSentinel is an immortal immovable object (undefined) so no
   // write-barrier is needed.
   __ bind(&megamorphic);
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ str(ip, FieldMemOperand(r2, JSGlobalPropertyCell::kValueOffset));
+  __ jmp(&done);
 
   // An uninitialized cache is patched with the function or sentinel to
   // indicate the ElementsKind if function is the Array constructor.
   __ bind(&initialize);
   // Make sure the function is the Array() function
   __ LoadArrayFunction(r3);
   __ cmp(r1, r3);
   __ b(ne, &not_array_function);
 
   // The target function is the Array constructor, install a sentinel value in
@@ skipping 2655 matching lines @@
      __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM