From: "Richard Guenther" <richard.guenther@gmail.com>
To: "Bernd Schmidt" <bernds_cb1@t-online.de>
Cc: "Daniel Berlin" <dberlin@dberlin.org>,
"GCC Patches" <gcc-patches@gcc.gnu.org>,
"Diego Novillo" <dnovillo@redhat.com>
Subject: Re: Reload bug & SRA oddness
Date: Sat, 28 Apr 2007 21:26:00 -0000 [thread overview]
Message-ID: <84fc9c000704281348y41c90c73g555a1113d7ff33ee@mail.gmail.com> (raw)
In-Reply-To: <46338870.7060006@t-online.de>
On 4/28/07, Bernd Schmidt <bernds_cb1@t-online.de> wrote:
> Daniel Berlin wrote:
> > It would also be a mistake to try to do significant optimization of
> > copy in/out placement directly in SRA. Again, that is why we have PRE
> > and DSE. If they are not moving/eliminating these things, they need
> > to be fixed.
>
> I've had a look at why these statements are not eliminated. I figure
> that dce is the pass that should get rid of them, but it doesn't. From
> the dumps:
>
> # SFT.70_14 = VDEF <SFT.70_13(D)>
> y.k = y$k_9(D);
> # VUSE <sD_15(D)>
> # SFT.70_19 = VDEF <SFT.70_14>
> # SFT.71_20 = VDEF <SFT.71_16(D)>
> # SFT.72_21 = VDEF <SFT.72_17(D)>
> # SFT.73_22 = VDEF <SFT.73_18(D)>
> y = sD;
>
> Note how all the VDEFs have an input argument, which causes us to
> believe that the second statement depends on the first. AFAICT, these
> VDEFs should have no arguments, but the compiler always generates them
> with exactly one input. I've tried to fix that, but so far the patch I
> have is only useful as an SSA learning tool for myself, as it creates
> lots of failures elsewhere in the compiler...
>
> Any other ideas how to address this?
These are all the default SSA_NAMEs of the SFTs (note the (D)). If
y is a local variable DCE should "ignore" them (those uses are undefined
in that case). So the only relevant VDEF for DCE/DSE is
# SFT.70_19 = VDEF <SFT.70_14>
So it's a DCE problem, not a problem of the SSA form.
Richard.
>
> Bernd
> --
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next prev parent reply other threads:[~2007-04-28 20:48 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-20 0:29 Bernd Schmidt
2007-04-20 3:19 ` Andrew Pinski
2007-04-20 3:53 ` Daniel Berlin
2007-04-20 4:30 ` Bernd Schmidt
2007-04-20 4:48 ` Andrew Pinski
2007-04-20 7:32 ` Alexandre Oliva
2007-04-20 12:57 ` Bernd Schmidt
2007-04-20 18:28 ` Alexandre Oliva
2007-04-20 18:40 ` Alexandre Oliva
2007-04-30 10:09 ` Bernd Schmidt
2007-04-30 19:04 ` Alexandre Oliva
2007-04-30 19:08 ` Alexandre Oliva
2007-05-01 15:38 ` Alexandre Oliva
2007-05-01 15:45 ` Eric Botcazou
2007-05-04 0:19 ` Alexandre Oliva
2007-05-01 15:53 ` Diego Novillo
2007-05-01 16:03 ` Eric Botcazou
2007-05-01 16:51 ` Arnaud Charlet
2007-05-01 16:54 ` Arnaud Charlet
2007-05-01 17:31 ` Andreas Schwab
2007-05-01 16:24 ` Roman Zippel
2007-05-04 4:07 ` Alexandre Oliva
2007-05-04 5:24 ` Alexandre Oliva
2007-05-05 18:19 ` Roman Zippel
2007-05-06 5:13 ` Alexandre Oliva
2007-05-06 12:13 ` Bernd Schmidt
2007-05-06 14:27 ` Alexandre Oliva
2007-05-06 15:01 ` Alexandre Oliva
2007-05-06 23:44 ` Alexandre Oliva
2007-05-06 23:51 ` Diego Novillo
2007-05-07 0:14 ` Alexandre Oliva
2007-05-07 2:21 ` Andrew Pinski
2007-05-09 12:25 ` Bernd Schmidt
2007-05-10 7:47 ` Alexandre Oliva
2007-05-10 11:00 ` Bernd Schmidt
2007-05-22 7:09 ` Alexandre Oliva
2007-05-22 17:34 ` Roman Zippel
2007-05-22 20:49 ` Alexandre Oliva
2007-05-23 13:07 ` Roman Zippel
2007-05-22 21:23 ` Alexandre Oliva
2007-05-09 18:32 ` Roman Zippel
2007-05-10 7:49 ` Alexandre Oliva
2007-05-15 17:39 ` Alexandre Oliva
2007-05-17 21:17 ` Andrew Pinski
2007-05-28 10:49 ` Bernd Schmidt
2007-05-31 20:57 ` Alexandre Oliva
2007-06-02 17:41 ` Bernd Schmidt
2007-06-06 3:18 ` Alexandre Oliva
2007-06-25 18:48 ` Alexandre Oliva
2007-06-26 23:01 ` Bernd Schmidt
2007-06-28 4:50 ` Alexandre Oliva
2007-07-03 0:52 ` Roman Zippel
2007-07-06 9:21 ` Alexandre Oliva
2007-08-24 7:28 ` SRA bit-field optimization (was: Re: Reload bug & SRA oddness) Alexandre Oliva
2007-09-28 9:17 ` SRA bit-field optimization Alexandre Oliva
2007-10-02 17:15 ` Richard Guenther
2007-10-03 8:38 ` Richard Sandiford
2007-10-03 16:50 ` Alexandre Oliva
2007-10-03 18:23 ` Richard Sandiford
2007-10-04 19:56 ` Richard Sandiford
2007-10-05 17:43 ` Alexandre Oliva
2007-10-06 8:02 ` Richard Sandiford
2007-10-06 21:06 ` John David Anglin
2007-10-06 22:12 ` Richard Sandiford
2007-10-07 23:44 ` Alexandre Oliva
2007-10-08 21:14 ` John David Anglin
2007-10-08 23:51 ` Alexandre Oliva
2007-10-09 0:31 ` John David Anglin
2007-10-09 4:41 ` Alexandre Oliva
2007-10-09 4:45 ` Alexandre Oliva
2007-10-06 16:01 ` David Daney
2007-10-03 14:37 ` Daniel Berlin
2007-10-03 14:44 ` Diego Novillo
2007-10-05 15:03 ` Richard Guenther
2007-10-05 16:20 ` Alexandre Oliva
2007-10-05 16:24 ` Richard Guenther
2007-10-05 16:26 ` Diego Novillo
2007-10-05 20:08 ` Alexandre Oliva
2007-10-09 4:55 ` Alexandre Oliva
2007-10-03 7:45 ` Eric Botcazou
2007-10-03 21:36 ` Eric Botcazou
2007-10-08 20:28 ` Alexandre Oliva
2007-10-05 6:24 ` Eric Botcazou
2007-10-05 16:03 ` Alexandre Oliva
2007-10-07 9:01 ` Eric Botcazou
2007-10-07 23:58 ` Alexandre Oliva
2007-10-08 5:13 ` Eric Botcazou
2007-10-08 20:29 ` Alexandre Oliva
2007-10-08 21:00 ` Eric Botcazou
2007-10-08 23:56 ` Alexandre Oliva
2007-09-29 17:52 ` Reload bug & SRA oddness Diego Novillo
2007-04-20 17:07 ` Daniel Berlin
2007-04-28 20:48 ` Bernd Schmidt
2007-04-28 21:26 ` Richard Guenther [this message]
2007-04-28 21:49 ` Daniel Berlin
2007-04-29 10:04 ` Richard Guenther
2007-04-29 10:27 ` Richard Guenther
2007-04-29 10:31 ` Richard Guenther
2007-04-29 11:16 ` Richard Guenther
2007-04-20 14:01 ` Bernd Schmidt
2007-04-20 22:00 ` Eric Botcazou
2007-04-28 16:25 ` Bernd Schmidt
2007-04-28 17:46 ` Eric Botcazou
2007-04-29 6:42 ` Bernd Schmidt
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