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

src/ia32/lithium-codegen-ia32.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 1753 matching lines @@
           __ test(ToRegister(left), Immediate(0x80000000));
           DeoptimizeIf(not_zero, instr->environment());
         } else {
           __ shr(ToRegister(left), shift_count);
         }
         break;
       case Token::SHL:
         if (shift_count != 0) {
           if (instr->hydrogen_value()->representation().IsSmi() &&
               instr->can_deopt()) {
-            __ shl(ToRegister(left), shift_count - 1);
+            if (shift_count != 1) {
+              __ shl(ToRegister(left), shift_count - 1);
+            }
             __ SmiTag(ToRegister(left));
             DeoptimizeIf(overflow, instr->environment());
           } else {
             __ shl(ToRegister(left), shift_count);
           }
         }
         break;
       default:
         UNREACHABLE();
         break;
@@ skipping 4738 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32