Tree profilng merge 1 - allow inserting onto edge to EXIT_BLOCK

[Paolo Bonzini]

Jeffrey A Law wrote:

> Keep me informed -- how you do this has some implications for
> Andrew's code (which I've taken review responsibility for) to
> optimize stuff like
 >
 > if (cond)
 >   return x;
 > else
 >   return y;

I planned to do this as part of a general rewrite of phiopt (see earlier 
message to the list in which I CCed you).  Is Andrew rewriting this to

  if (cond)
    T = x;
  else
    T = y;
   return T;

?

Paolo