From: Eric Botcazou <ebotcazou@libertysurf.fr>
To: Jan Hubicka <jh@suse.cz>
Cc: gcc@gcc.gnu.org
Subject: Re: Reload bug
Date: Sun, 13 Apr 2003 19:57:00 -0000 [thread overview]
Message-ID: <200304130947.53856.ebotcazou@libertysurf.fr> (raw)
In-Reply-To: <20030412142751.GD31150@kam.mff.cuni.cz>
> > The function appears to assume that reg XREGNO supports mode YMODE. Is
> > that by design? If so, I think you should mention it in the header
> > comment.
>
> Hmm, I am not certain what should happen there. We can either verify it
> here or the place we are doing so already...
I think we should verify that the subreg is really representable. For low
parts, it's HARD_REGNO_MODE_OK (xregno, ymode) == 1. Are you sure that we
should not verify that HARD_REGNO_MODE_OK (xregno + offset, ymode) == 1
at the very end of the function either, like in the original code?
> > I think you should mention that the second "if" catches paradoxical
> > subregs too.
>
> Hmm, you are right. Then we can remove the first if too :)
Even for big-endian platforms? I think the first "if" in the original code
catches paradoxical subregs on big-endian platforms and the second "if"
catches them on little-endian platforms.
> No, I am actually trying to compute the size of the one ymode register
> in order to be able to compensate the lowpart operation.
> Imagine (subreg:QI (reg:DI) 3) is valid on little endian with
> nregs_ymode == 2
I presume you mean big-endian? And nregs_xmode == 2?
Then wouldn't the following formula be better?
offset -= subreg_lowpart_offset (mode_for_size (GET_MODE_SIZE (ymode)
/ nregs_ymode, MODE_INT, 0),
mode_for_size (GET_MODE_SIZE (xmode)
/ nregs_xmode, MODE_INT, 0));
It looks certainly more homogeneous than the former.
--
Eric Botcazou
next prev parent reply other threads:[~2003-04-13 7:54 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-08 18:52 Eric Botcazou
2003-04-08 23:16 ` Jan Hubicka
2003-04-09 0:44 ` Jan Hubicka
2003-04-09 7:00 ` Eric Botcazou
2003-04-09 3:00 ` Eric Botcazou
2003-04-09 9:49 ` Jan Hubicka
2003-04-09 8:57 ` Eric Botcazou
2003-04-09 9:45 ` Jan Hubicka
2003-04-09 9:50 ` Eric Botcazou
2003-04-09 14:52 ` Jan Hubicka
2003-04-09 18:10 ` Eric Botcazou
2003-04-09 19:15 ` Jan Hubicka
2003-04-10 14:25 ` Eric Botcazou
2003-04-10 16:31 ` Jan Hubicka
2003-04-10 16:35 ` Jan Hubicka
2003-04-10 20:21 ` Eric Botcazou
2003-04-10 20:43 ` Jan Hubicka
2003-04-11 14:44 ` Eric Botcazou
2003-04-11 17:49 ` Jan Hubicka
2003-04-11 18:09 ` Jan Hubicka
2003-04-11 19:01 ` Jan Hubicka
2003-04-11 19:07 ` Jan Hubicka
2003-04-12 14:55 ` Eric Botcazou
2003-04-12 17:45 ` Jan Hubicka
2003-04-13 19:57 ` Eric Botcazou [this message]
2003-04-13 20:04 ` Jan Hubicka
2003-04-12 17:55 ` Make reload to avoid invalid subregs Jan Hubicka
2003-04-17 22:32 ` Richard Henderson
2003-04-10 20:51 ` Reload bug Dale Johannesen
2003-04-09 9:13 ` Eric Botcazou
2003-04-09 11:25 ` Jan Hubicka
2003-04-09 12:04 ` Eric Botcazou
2003-04-09 18:05 ` Jan Hubicka
2003-04-09 18:26 ` Eric Botcazou
2003-04-09 21:23 ` Richard Henderson
-- strict thread matches above, loose matches on Subject: below --
1999-09-01 8:40 Andreas Schwab
1999-09-02 0:32 ` Jeffrey A Law
1999-09-02 2:15 ` Andreas Schwab
1999-09-30 18:02 ` Andreas Schwab
1999-09-30 18:02 ` Jeffrey A Law
1999-09-30 18:02 ` Andreas Schwab
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