Add ToBoolean-conversion of constants in Crankshaft and use it when generating a branch based on ...

src/hydrogen-instructions.h

 // Copyright 2011 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 1943 matching lines @@
     ASSERT(HasInteger32Value());
     return int32_value_;
   }
   bool HasDoubleValue() const { return has_double_value_; }
   double DoubleValue() const {
     ASSERT(HasDoubleValue());
     return double_value_;
   }
   bool HasStringValue() const { return handle_->IsString(); }
 
+  bool ToBoolean() const;
+
   virtual intptr_t Hashcode() {
     ASSERT(!HEAP->allow_allocation(false));
     return reinterpret_cast<intptr_t>(*handle());
   }
 
 #ifdef DEBUG
   virtual void Verify() { }
 #endif
 
   DECLARE_CONCRETE_INSTRUCTION(Constant, "constant")
@@ skipping 1674 matching lines @@
   HValue* object() { return left(); }
   HValue* key() { return right(); }
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_