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

src/mips/code-stubs-mips.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
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@@ skipping 5140 matching lines @@
 
   // A monomorphic miss (i.e, here the cache is not uninitialized) goes
   // megamorphic.
   __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
   __ Branch(&initialize, eq, a3, Operand(at));
   // MegamorphicSentinel is an immortal immovable object (undefined) so no
   // write-barrier is needed.
   __ bind(&megamorphic);
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
   __ sw(at, FieldMemOperand(a2, 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(a3);
   __ Branch(&not_array_function, ne, a1, Operand(a3));
 
   // The target function is the Array constructor, install a sentinel value in
   // the constructor's type info cell that will track the initial ElementsKind
@@ skipping 2677 matching lines @@
      __ Jump(generic_construct_stub, RelocInfo::CODE_TARGET);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS