Re: transforming expressions

replacing expressions "in place" is not a good idea. Instead, try to organize
your program so it can work in the following way:

-write a function: Expression * replace(Expression *) that will take e1 as argument and return a _newly_  
created SgFunctionCallExp. 

-use the SgExpression::setLhs(), SgExpression::setRhs(), or SgStatement::setExpression(int i,  
SgExpression &e) methods to replace e1 by the expression returned by the replace function.