Re: [Bug rtl-optimization/23585] [4.0 regression] mem_fun* code fine with -O1, bus error with -O2

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Oct 11, 2005, at 9:51 AM, ebotcazou at gcc dot gnu dot org wrote:

> ------- Comment #8 from ebotcazou at gcc dot gnu dot org  2005-10-11 
> 13:51 -------
> > Yes, I think the problem is in delay slot scheduling too. COND_EXPR 
> > means that
> > either branch must not be evaluated because it could be illegal; if 
> > you hoist a
> > mem from a branch into the delay slot of the condition, you are 
> > effectively
> > partially evaluting the branch.
>
> Yes, that makes sense.  At the moment the predicate used in reorg.c is
> may_trap_p so we would need to detect faulting instructions too.

may_trap_p is the correct thing as it should detect this instruction as
trapping:


      /* Memory ref can trap unless it's a static var or a stack slot.  
*/
    case MEM:
      if (MEM_NOTRAP_P (x))
        return 0;
      return rtx_addr_can_trap_p (XEXP (x, 0));


-- Pinski