Re: CFG

[Jeffrey A Law <law at cygnus dot com>]

  In message <Pine.GSO.4.10.10006281746080.16817-100000@xingu.dcc.unicamp.br>yo
u write:
  > 
  > 
  > 	Good Morning (afternoon) to all...
  >         Could you please help me? I want to know if the CFG constructed
  >  in the dataflow analysis is updated at each step subsequent steps of
  >  the compilation, and, in turn, remains until the Final phase of the
  >  compilation process. I want to transform the CFG into another structure
  >  but only after all the optimizations have been made over it. I know
  >  that the almost all optimizations are made over the RTL expressions,
  >  but I don't know if some optimization touchs the CFG. 
  >         In other words, I would like to know if the CFG is destructed      
  >   
  >  after the dataflow analysis, i.e., after the informations provided
  >  by the CFG are recorded for futures uses, or if the CFG remains        
  >  untouchable.
Most of the time we [re]build the cfg when we need it (ie, we don't assume
it's valid, except in a few special cases).  Most of the optimizers are
not using the cfg right now and do not keep it accurate.
jeff