From: Julian Brown <julian@codesourcery.com>
To: gcc@gcc.gnu.org
Subject: Re: I have questions regarding the 4.3 codebase...
Date: Thu, 23 Mar 2023 07:08:34 +0000 [thread overview]
Message-ID: <20230323070834.17026a71@squid.athome> (raw)
In-Reply-To: <CAGx9W7gFng6yazrgAcSn6ShGZXFJUBCQoEKp91uyt65S4wM_Qg@mail.gmail.com>
On Wed, 22 Mar 2023 18:27:28 -0400
Sid Maxwell via Gcc <gcc@gcc.gnu.org> wrote:
> Is there anyone on the list with experience with the gcc 4.3
> codebase? I'm currently maintaining a fork of it, with a PDP10 code
> generator.
>
> I've run into an issue involving the transformation of a movmemhi to a
> single PDP10 instruction (an xblt, if you're curious). The
> transformation appears to 'lose' its knowledge of being a store,
> resulting in certain following stores being declared dead, and code
> motion that shouldn't happen (e.g. a load moved before the xblt that
> depends on the result of the xblt).
>
> I'm hoping to find someone who can help me diagnose the problem. We
> want to use this instruction rather than the copy-word-loop currently
> generated for struct assignments.
I think we'd need a bit more info than that... what does the movmemhi
instruction pattern look like, for example?
Julian
next prev parent reply other threads:[~2023-03-23 7:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-22 22:27 Sid Maxwell
2023-03-23 7:08 ` Julian Brown [this message]
2023-03-23 14:13 ` Sid Maxwell
2023-03-23 14:29 ` Paul Koning
2023-03-23 14:32 ` Sid Maxwell
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