From: Nathan Sidwell <nathan@codesourcery.com>
To: Daniel Towner <daniel.towner@picochip.com>
Cc: gcc@gcc.gnu.org
Subject: Re: Incorrect DFA scheduling of output dependency.
Date: Mon, 06 Dec 2004 12:30:00 -0000 [thread overview]
Message-ID: <41B450BF.2090707@codesourcery.com> (raw)
In-Reply-To: <41B442B7.9020408@picochip.com>
Daniel,
> I am using the DFA scheduler to implement VLIW scheduling for a 16-bit
> DSP. Recently I have come across an apparent bug in the scheduler.
> Consider the following sequence of instructions, with DFA scheduling
> turned off:
>
> Now the DFA scheduler has grouped the four instructions into two VLIW
> packets. However, the first of these packets contains an instruction
> which writes to R3, and which reads from R3. Thus, the wrong value of R3
> is shifted into R5. It appears that the output dependency of the initial
> instruction is not being respected?
something is wrong with your scheduler description, but I know not what :)
You need to tell the scheduler about the bundling, how are you doing that?
nathan
--
Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery LLC
nathan@codesourcery.com :: http://www.planetfall.pwp.blueyonder.co.uk
next prev parent reply other threads:[~2004-12-06 12:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-06 11:30 Daniel Towner
2004-12-06 12:30 ` Nathan Sidwell [this message]
2004-12-06 12:31 ` Steven Bosscher
2004-12-06 16:27 ` Daniel Towner
2004-12-06 17:12 ` Vladimir Makarov
2004-12-07 10:59 ` Daniel Towner
2004-12-07 13:01 ` Steven Bosscher
2004-12-07 13:15 ` Steven Bosscher
2004-12-07 13:26 ` Jeffrey A Law
2004-12-07 13:40 ` Daniel Berlin
2004-12-07 22:15 ` Vladimir N. Makarov
[not found] ` <41B6360E.6010806@redhat.com>
2004-12-08 9:53 ` Daniel Towner
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