#define SOMETHING1 STMT_START { assert( something ); if(some_complex_condition) wrapped_function1( aTHX_, ... ); assert(something_else ) } STMT_END
#define SOMETHING2 STMT_START { assert( something ); if(some_complex_condition) wrapped_function2( aTHX_, ... ); assert(something_else ) } STMT_END
#define SOMETHING3 STMT_START { assert( something ); if(some_complex_condition) wrapped_function3( aTHX_, ... ); assert(something_else ) } STMT_END

int someFunction( aTHX_  ... ) {
    dATHX;
    
    ...;
    SOMETHING1( ... );
    ...;
    SOMETHING2( ... );
    ...;
    SOMETHING3( ... );
    RETURN;
}