Re: -fomit-frame-pointer interaction with alloca - egcs-1.0.1

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

  In message <01BD3588.B361D700@malvinas.AtlanTech.COM>you write:
  > Jeff writes:
  > Jeff> Thanks for the testcase.
  > 
  > Well, here's another.  (I patched my egcs to fix the sp update on exit).
  > 
  > Looks like conditional expressions can force unneccesary sp updates:
  > 
  > 	int dbdir_sort_date (int first_private, int second_private) {
  > 	        char * name = alloca (( 256 ) + 1) ;
  > 	        fred (name);
  > 	        return first_private < second_private ? -1 : 0 ;
  > 	}
I suspect this happens because we initially generate compare/jump sequences
(which must do the sp adjustments).  Then we optimize the compare/jump
sequences into a conditional move during the first jump optimization pass.

The obvious solution is to move the conditional move support earlier in
the compiler....  If that is indeed the problem.

jeff