remove_complex: modify expressions only when necessary

Author: tautschnig

src/goto-programs/remove_complex.cpp

@@ -47,6 +47,90 @@ static exprt complex_member(const exprt &expr, irep_idt id)
 
 /*******************************************************************\
 
+Function: have_to_remove_complex
+
+  Inputs:
+
+ Outputs:
+
+ Purpose:
+
+\*******************************************************************/
+
+static bool have_to_remove_complex(const typet &type);
+
+static bool have_to_remove_complex(const exprt &expr)
+{
+  if(expr.id()==ID_typecast &&
+     to_typecast_expr(expr).op().type().id()==ID_complex &&
+     expr.type().id()!=ID_complex)
+    return true;
+
+  if(expr.type().id()==ID_complex)
+  {
+    if(expr.id()==ID_plus || expr.id()==ID_minus ||
+       expr.id()==ID_mult || expr.id()==ID_div)
+      return true;
+    else if(expr.id()==ID_unary_minus)
+      return true;
+    else if(expr.id()==ID_complex)
+      return true;
+    else if(expr.id()==ID_typecast)
+      return true;
+  }
+
+  if(expr.id()==ID_complex_real)
+    return true;
+  else if(expr.id()==ID_complex_imag)
+    return true;
+
+  if(have_to_remove_complex(expr.type()))
+     return true;
+
+  forall_operands(it, expr)
+    if(have_to_remove_complex(*it))
+      return true;
+
+  return false;
+}
+
+/*******************************************************************\
+
+Function: have_to_remove_complex
+
+  Inputs:
+
+ Outputs:
+
+ Purpose:
+
+\*******************************************************************/
+
+static bool have_to_remove_complex(const typet &type)
+{
+  if(type.id()==ID_struct || type.id()==ID_union)
+  {
+    const struct_union_typet &struct_union_type=
+      to_struct_union_type(type);
+    for(struct_union_typet::componentst::const_iterator
+        it=struct_union_type.components().begin();
+        it!=struct_union_type.components().end();
+        it++)
+      if(have_to_remove_complex(it->type()))
+        return true;
+  }
+  else if(type.id()==ID_pointer ||
+          type.id()==ID_vector ||
+          type.id()==ID_array)
+    return have_to_remove_complex(type.subtype());
+  else if(type.id()==ID_complex)
+    return true;
+
+  return false;
+}
+
+/*******************************************************************\
+
 Function: remove_complex
 
 Inputs:
@@ -61,6 +145,9 @@ static void remove_complex(typet &);
 
 static void remove_complex(exprt &expr)
 {
+  if(!have_to_remove_complex(expr))
+    return;
+
   if(expr.id()==ID_typecast)
   {
     assert(expr.operands().size()==1);
@@ -201,6 +288,9 @@ Purpose: removes complex data type
 
 static void remove_complex(typet &type)
 {
+  if(!have_to_remove_complex(type))
+    return;
+
   if(type.id()==ID_struct || type.id()==ID_union)
   {
     struct_union_typet &struct_union_type=