Merge pull request diffblue#4301 from romainbrenguier/refactor/simplify_expr_copy

 Make simplify_expr take copy instead of reference

Author: tautschnig

src/analyses/ai_domain.cpp

@@ -48,7 +48,7 @@ bool ai_domain_baset::ai_simplify_lhs(exprt &condition, const namespacet &ns)
     index_exprt ie = to_index_expr(condition);
     bool no_simplification = ai_simplify(ie.index(), ns);
     if(!no_simplification)
-      condition = simplify_expr(ie, ns);
+      condition = simplify_expr(std::move(ie), ns);
 
     return no_simplification;
   }
@@ -57,7 +57,7 @@ bool ai_domain_baset::ai_simplify_lhs(exprt &condition, const namespacet &ns)
     dereference_exprt de = to_dereference_expr(condition);
     bool no_simplification = ai_simplify(de.pointer(), ns);
     if(!no_simplification)
-      condition = simplify_expr(de, ns); // So *(&x) -> x
+      condition = simplify_expr(std::move(de), ns); // So *(&x) -> x
 
     return no_simplification;
   }
@@ -70,7 +70,7 @@ bool ai_domain_baset::ai_simplify_lhs(exprt &condition, const namespacet &ns)
     // must also be addressable
     bool no_simplification = ai_simplify_lhs(me.compound(), ns);
     if(!no_simplification)
-      condition = simplify_expr(me, ns);
+      condition = simplify_expr(std::move(me), ns);
 
     return no_simplification;
   }

src/analyses/custom_bitvector_analysis.cpp

@@ -529,8 +529,7 @@ void custom_bitvector_domaint::transform(
       if(to!=from->get_target())
         guard = boolean_negate(guard);
 
-      exprt result=eval(guard, cba);
-      exprt result2=simplify_expr(result, ns);
+      const exprt result2 = simplify_expr(eval(guard, cba), ns);
 
       if(result2.is_false())
         make_bottom();
@@ -787,7 +786,7 @@ void custom_bitvector_analysist::check(
 
         exprt tmp = eval(i_it->get_condition(), i_it);
         const namespacet ns(goto_model.symbol_table);
-        result=simplify_expr(tmp, ns);
+        result = simplify_expr(std::move(tmp), ns);
 
         description=i_it->source_location.get_comment();
       }

src/goto-analyzer/taint_analysis.cpp

@@ -343,9 +343,7 @@ bool taint_analysist::operator()(
 
         exprt result =
           custom_bitvector_analysis.eval(i_it->get_condition(), i_it);
-        exprt result2=simplify_expr(result, ns);
-
-        if(result2.is_true())
+        if(simplify_expr(std::move(result), ns).is_true())
           continue;
 
         if(first)

src/goto-instrument/accelerate/acceleration_utils.cpp

@@ -1120,13 +1120,13 @@ bool acceleration_utilst::assign_array(
   {
     replace_expr(
       loop_counter, from_integer(0, loop_counter.type()), lower_bound);
-    simplify_expr(lower_bound, ns);
+    lower_bound = simplify_expr(std::move(lower_bound), ns);
   }
   else
   {
     replace_expr(
       loop_counter, from_integer(0, loop_counter.type()), upper_bound);
-    simplify_expr(upper_bound, ns);
+    upper_bound = simplify_expr(std::move(upper_bound), ns);
   }
 
   if(stride==0)

src/solvers/lowering/byte_operators.cpp

@@ -1012,7 +1012,7 @@ exprt lower_byte_extract(const byte_extract_exprt &src, const namespacet &ns)
     }
 
     if(!failed)
-      return simplify_expr(s, ns);
+      return simplify_expr(std::move(s), ns);
   }
   else if(src.type().id() == ID_union || src.type().id() == ID_union_tag)
   {
@@ -1183,7 +1183,7 @@ static exprt lower_byte_update_byte_array_vector(
       result.add_to_operands(where, update_value);
   }
 
-  return simplify_expr(result, ns);
+  return simplify_expr(std::move(result), ns);
 }
 
 /// Apply a byte update \p src to an array/vector typed operand, using the byte
@@ -1328,7 +1328,7 @@ static exprt lower_byte_update_array_vector_non_const(
     result.add_to_operands(std::move(where), std::move(element));
   }
 
-  return simplify_expr(result, ns);
+  return simplify_expr(std::move(result), ns);
 }
 
 /// Apply a byte update \p src to an array/vector typed operand using the byte

src/util/simplify_expr.cpp

@@ -2574,9 +2574,8 @@ bool simplify(exprt &expr, const namespacet &ns)
   return simplify_exprt(ns).simplify(expr);
 }
 
-exprt simplify_expr(const exprt &src, const namespacet &ns)
+exprt simplify_expr(exprt src, const namespacet &ns)
 {
-  exprt tmp=src;
-  simplify_exprt(ns).simplify(tmp);
-  return tmp;
+  simplify_exprt(ns).simplify(src);
+  return src;
 }

src/util/simplify_expr.h

@@ -25,6 +25,6 @@ bool simplify(
   const namespacet &ns);
 
 // this is the preferred interface
-exprt simplify_expr(const exprt &src, const namespacet &ns);
+exprt simplify_expr(exprt src, const namespacet &ns);
 
 #endif // CPROVER_UTIL_SIMPLIFY_EXPR_H

unit/solvers/strings/string_constraint_generator_valueof/is_digit_with_radix.cpp

@@ -29,7 +29,9 @@ static exprt actual(
   const namespacet ns(symtab);
 
   return simplify_expr(
-    is_digit_with_radix(chr, strict_formatting, radix_as_char, radix_ul), ns);
+    is_digit_with_radix(
+      std::move(chr), strict_formatting, radix_as_char, radix_ul),
+    ns);
 }
 
 /// Get the simplified return value of is_digit_with_radix called with a radix