
void main()
main: scope:[main]  from
  [0] main::screen = (char *) 1024
  [1] call sub
  to:main::@1
main::@1: scope:[main]  from main
  [2] phi()
  [3] call sub
  to:main::@return
main::@return: scope:[main]  from main::@1
  [4] return 
  to:@return

void sub(char ch , char **dst)
sub: scope:[sub]  from main main::@1
  [5] sub::ch#2 = phi( main/'a', main::@1/'b' )
  [6] *(*main::pscreen) = sub::ch#2
  [7] *main::pscreen = ++ *main::pscreen
  to:sub::@return
sub::@return: scope:[sub]  from sub
  [8] return 
  to:@return
