Re: [PATCH] Use reversed_comparison_code in sched-deps.c

[Richard Earnshaw <rearnsha at buzzard dot freeserve dot co dot uk>]

graham.stott@btinternet.com said:
> This patch breaks bootstraps with RTL checking enabled on i686-pc-linux-gn
> u

> Your changes to get_condition trigget

> crtstuff.c: In function `frame_dummy': crtstuff.c:323: internal compiler
> error: RTL check: access of elt 2 of `eq' with last elt 1 in
> get_condition, at sched-deps.c:156

> This is the offending code

>    cond = XEXP (SET_SRC (pc_set (insn)), 0);
>    if (XEXP (cond, 2) == pc_rtx)
>      return cond; 

Argh!  Somehow I managed to run the tests with checking disabled.

> All,
> 
> Just a follow on while I still awake
> 
> Graham Stott wrote:
> > Richard,
> 
> > 
> >   cond = XEXP (SET_SRC (pc_set (insn)), 0);
> >   if (XEXP (cond, 2) == pc_rtx)
>                      ^ I suspect this should be 0
> >     return cond;
> > 
> 
> I'm trying an overnight bootstrap with that change.

No, it's looking inside the if_then_else too soon (I over optimized the 
code :-( )

Here's the patch I'm testing now (with checking back on this time)...

Sorry about that.

R.

Index: sched-deps.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/sched-deps.c,v
retrieving revision 1.77
diff -p -p -r1.77 sched-deps.c
*** sched-deps.c	29 Aug 2004 21:07:37 -0000	1.77
--- sched-deps.c	30 Aug 2004 00:57:14 -0000
*************** get_condition (rtx insn)
*** 152,163 ****
    if (!any_condjump_p (insn) || !onlyjump_p (insn))
      return 0;
  
!   cond = XEXP (SET_SRC (pc_set (insn)), 0);
    if (XEXP (cond, 2) == pc_rtx)
!     return cond;
    else if (XEXP (cond, 1) == pc_rtx)
      {
!       enum rtx_code revcode = reversed_comparison_code (cond, insn);
  
        if (revcode == UNKNOWN)
  	return 0;
--- 152,166 ----
    if (!any_condjump_p (insn) || !onlyjump_p (insn))
      return 0;
  
!   cond = SET_SRC (pc_set (insn));
    if (XEXP (cond, 2) == pc_rtx)
!     return XEXP (cond, 0);
    else if (XEXP (cond, 1) == pc_rtx)
      {
!       enum rtx_code revcode;
! 
!       cond = XEXP (cond, 0);
!       revcode = reversed_comparison_code (cond, insn);
  
        if (revcode == UNKNOWN)
  	return 0;