On Fri, 2015-04-17 at 16:49 +0200, Jakub Jelinek wrote:
> 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.
Yes, sorry, I had just noticed that. I forgot to download the revised
patch to the system I send my mail from. This is what I get for
multitasking during a meeting...
>
> 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;
Hm, yes, there is definitely a problem here. Let me look at reworking
this. Thanks!
Bill
>
> Jakub
>
