Merge pull request #3104 from diffblue/bitwise_neg

remove bitwise_neg(mp_integer)

Author: Daniel Kroening

src/goto-programs/interpreter_evaluate.cpp

@@ -528,7 +528,9 @@ void interpretert::evaluate(
     evaluate(expr.op0(), tmp);
     if(tmp.size()==1)
     {
-      dest.push_back(bitwise_neg(tmp.front()));
+      const auto width = to_bitvector_type(expr.op0().type()).get_width();
+      const mp_integer mask = power(2, width) - 1;
+      dest.push_back(bitwise_xor(tmp.front(), mask));
       return;
     }
   }

src/util/mp_arith.cpp

@@ -249,16 +249,6 @@ mp_integer bitwise_xor(const mp_integer &a, const mp_integer &b)
   return result;
 }
 
-/// bitwise negation bitwise operations only make sense on native objects, hence
-/// the largest object size should be the largest available c++ integer size
-/// (currently long long)
-mp_integer bitwise_neg(const mp_integer &a)
-{
-  PRECONDITION(a.is_ulong());
-  ullong_t result=~a.to_ulong();
-  return result;
-}
-
 /// arithmetic left shift bitwise operations only make sense on native objects,
 /// hence the largest object size should be the largest available c++ integer
 /// size (currently long long)

src/util/mp_arith.h

@@ -27,7 +27,6 @@ mp_integer operator<<(const mp_integer &, const mp_integer &);
 mp_integer bitwise_or(const mp_integer &, const mp_integer &);
 mp_integer bitwise_and(const mp_integer &, const mp_integer &);
 mp_integer bitwise_xor(const mp_integer &, const mp_integer &);
-mp_integer bitwise_neg(const mp_integer &);
 
 mp_integer arith_left_shift(
   const mp_integer &, const mp_integer &, std::size_t true_size);