This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH, 5.1, rs6000] Fix PR65787


On Fri, Apr 17, 2015 at 08:28:02AM -0500, Bill Schmidt wrote:
> On Fri, 2015-04-17 at 07:27 -0500, Bill Schmidt wrote:
> > Note that Jakub requested a small change in the bugzilla commentary,
> > which I've implemented.  I'm doing a regstrap now.
> > 
> > Bill
> > 
> 
> Here's the revised and tested patch.  OK for trunk and gcc-5-branch?

You have actually mailed the original patch again, not the revised one.

That said, PARALLEL seems to be already handled by rtx_is_swappable_p,
so if it isn't handled correctly, perhaps there is a bug in that function.

  for (i = 0; i < GET_RTX_LENGTH (code); ++i)
    if (fmt[i] == 'e' || fmt[i] == 'u')
      {
        unsigned int special_op = SH_NONE;
        ok &= rtx_is_swappable_p (XEXP (op, i), &special_op);
        /* Ensure we never have two kinds of special handling
           for the same insn.  */
        if (*special != SH_NONE && special_op != SH_NONE
            && *special != special_op)
          return 0;
        *special = special_op;
      }
    else if (fmt[i] == 'E')
      for (j = 0; j < XVECLEN (op, i); ++j)
        {
          unsigned int special_op = SH_NONE;
          ok &= rtx_is_swappable_p (XVECEXP (op, i, j), &special_op);
          /* Ensure we never have two kinds of special handling
             for the same insn.  */
          if (*special != SH_NONE && special_op != SH_NONE
              && *special != special_op)
            return 0;
          *special = special_op;
        }

If the comments are correct, then supposedly if say on the PARALLEL with
a SET that is SH_EXTRACT and a CLOBBER that is SH_NONE, both returning 1,
the outcome should by return 1 (that is the case), but *special should be
SH_EXTRACT, rather than the last case wins right now (SH_NONE).
If so, then perhaps after each of the ok &= rtx_is_swappable_p ...
line should be
  if (special_op == SH_NONE)
    continue;
so that we never store SH_NONE (leave that just to the initial store), and
then just
  if (*special != SH_NONE && *special != special_op)
    return 0;

	Jakub


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]