[avr-gcc-list] Re: bugfix for cselib_invalidate_regno

[Richard Earnshaw]

> Denis Chertykov <address@hidden> writes:
> 
> > I have founded a bug in cselib.c:cselib_invalidate_regno.
> > The avr port triggers this bug.
> > Current version of cselib_invalidate_regno didn't invalidate lower
> > register numbers if they contain values that overlap REGNO in case
> > that (regno < FIRST_PSEUDO_REGISTER && mode == VOIDmode). This happens
> > if cselib_invalidate_regno called from cselib_process_insn which
> > handle CALL_INSN.
> > IE
> > 
> >   /* If this is a call instruction, forget anything stored in a
> >      call clobbered register, or, if this is not a const call, in
> >      memory.  */
> >   if (GET_CODE (insn) == CALL_INSN)
> >     {
> >       for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
> >     if (call_used_regs[i])
> >       cselib_invalidate_regno (i, VOIDmode);
> > 
> > 
> > Can I apply the following patch to mainline and 3.3 branches ?
> > 
> > Denis.
> > 
> > 
> > Index: cselib.c
> > ===================================================================
> > RCS file: /cvsroot/gcc/egcs/gcc/cselib.c,v
> > retrieving revision 1.27
> > diff -c -3 -p -r1.27 cselib.c
> > *** cselib.c        17 Apr 2003 01:07:12 -0000      1.27
> > --- cselib.c        19 May 2003 11:09:38 -0000
> > *************** cselib_invalidate_regno (regno, mode)
> > *** 1019,1032 ****
> >        pseudos, only REGNO is affected.  For hard regs, we must take MODE
> >        into account, and we must also invalidate lower register numbers
> >        if they contain values that overlap REGNO.  */
> > !   if (regno < FIRST_PSEUDO_REGISTER && mode != VOIDmode) 
> >       {
> >         if (regno < max_value_regs)
> >     i = 0;
> >         else
> >     i = regno - max_value_regs;
> >   
> > !       endregno = regno + HARD_REGNO_NREGS (regno, mode);
> >       }
> >     else
> >       {
> > --- 1019,1033 ----
> >        pseudos, only REGNO is affected.  For hard regs, we must take MODE
> >        into account, and we must also invalidate lower register numbers
> >        if they contain values that overlap REGNO.  */
> > !   if (regno < FIRST_PSEUDO_REGISTER)
> >       {
> >         if (regno < max_value_regs)
> >     i = 0;
> >         else
> >     i = regno - max_value_regs;
> >   
> > !       endregno = regno
> > !   + (mode != VOIDmode ? HARD_REGNO_NREGS (regno, mode) : 1);
> >       }
> >     else
> >       {
> 
> Anybody, please, review my tiny patch.
> 
> Denis.
> 

Why not change the caller to pass reg_raw_mode[regno].  That seems much 
cleaner to me than pretending a hard register can have no mode.

R.