Don't generate a shift left by one if can deoptimize on ia32 and arm and mips.

src/mips/lithium-codegen-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
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@@ skipping 1565 matching lines @@
             __ And(at, left, Operand(0x80000000));
             DeoptimizeIf(ne, instr->environment(), at, Operand(zero_reg));
           }
           __ Move(result, left);
         }
         break;
       case Token::SHL:
         if (shift_count != 0) {
           if (instr->hydrogen_value()->representation().IsSmi() &&
               instr->can_deopt()) {
-            __ sll(result, left, shift_count - 1);
+            if (shift_count != 1) {
+              __ sll(result, left, shift_count - 1);
+            }
             __ SmiTagCheckOverflow(result, result, scratch);
             DeoptimizeIf(lt, instr->environment(), scratch, Operand(zero_reg));
           } else {
             __ sll(result, left, shift_count);
           }
         } else {
           __ Move(result, left);
         }
         break;
       default:
@@ skipping 4257 matching lines @@
   __ Subu(scratch, result, scratch);
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal