Fixed power-of-2 predicates, excluding 0.

src/hydrogen-instructions.h

 // 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 3743 matching lines @@
   void SetOperandPositions(Zone* zone,
                            HSourcePosition left_pos,
                            HSourcePosition right_pos) {
     set_operand_position(zone, 1, left_pos);
     set_operand_position(zone, 2, right_pos);
   }
 
   bool RightIsPowerOf2() {
     if (!right()->IsInteger32Constant()) return false;
     int32_t value = right()->GetInteger32Constant();
-    return value != 0 && (IsPowerOf2(value) || IsPowerOf2(-value));
+    return IsPowerOf2(value) || IsPowerOf2(-value);
   }
 
   DECLARE_ABSTRACT_INSTRUCTION(BinaryOperation)
 
  private:
   bool IgnoreObservedOutputRepresentation(Representation current_rep);
 
   Representation observed_input_representation_[2];
   Representation observed_output_representation_;
 };
@@ skipping 3752 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_