From: Hans-Peter Nilsson <hp@axis.com>
To: Hans-Peter Nilsson <hp@axis.com>
Cc: <gcc-patches@gcc.gnu.org>
Subject: 2nd Ping: Re: [PATCH v3] doc: Document order of define_peephole2 scanning
Date: Thu, 4 May 2023 02:09:25 +0200 [thread overview]
Message-ID: <20230504000925.DD5C320437@pchp3.se.axis.com> (raw)
In-Reply-To: <20230426235524.7A13C20405@pchp3.se.axis.com> (message from Hans-Peter Nilsson on Thu, 27 Apr 2023 01:55:24 +0200)
Ping again.
> From: Hans-Peter Nilsson <hp@axis.com>
> Date: Thu, 27 Apr 2023 01:55:24 +0200
>
> > From: Hans-Peter Nilsson <hp@axis.com>
> > Date: Wed, 19 Apr 2023 18:59:14 +0200
> [...]
>
> > So again: Approvers: pdf output reviewed. Ok to commit?
> > -- >8 --
> > I was a bit surprised when my newly-added define_peephole2 didn't
> > match, but it was because it was expected to partially match the
> > generated output of a previous define_peephole2, which matched and
> > modified the last insn of a sequence to be matched. I had assumed
> > that the algorithm backed-up the size of the match-buffer, thereby
> > exposing newly created opportunities *with sufficient context* to all
> > define_peephole2's. While things can change in that direction, let's
> > start with documenting the current state.
> >
> > * doc/md.texi (define_peephole2): Document order of scanning.
> > ---
> > gcc/doc/md.texi | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> > index 07bf8bdebffb..300d104d58ab 100644
> > --- a/gcc/doc/md.texi
> > +++ b/gcc/doc/md.texi
> > @@ -9362,6 +9362,15 @@ If the preparation falls through (invokes neither @code{DONE} nor
> > @code{FAIL}), then the @code{define_peephole2} uses the replacement
> > template.
> >
> > +Insns are scanned in forward order from beginning to end for each basic
> > +block. Matches are attempted in order of @code{define_peephole2}
> > +appearance in the @file{md} file. After a successful replacement,
> > +scanning for further opportunities for @code{define_peephole2}, resumes
> > +with the first generated replacement insn as the first insn to be
> > +matched against all @code{define_peephole2}. For the example above,
> > +after its successful replacement, the first insn that can be matched by
> > +a @code{define_peephole2} is @code{(set (match_dup 4) (match_dup 1))}.
> > +
> > @end ifset
> > @ifset INTERNALS
> > @node Insn Attributes
> > --
> > 2.30.2
> >
>
next prev parent reply other threads:[~2023-05-04 0:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-18 17:55 [PATCH] " Hans-Peter Nilsson
2023-04-18 18:32 ` Paul Koning
2023-04-18 18:44 ` Hans-Peter Nilsson
2023-04-19 3:15 ` [PATCH v2] " Hans-Peter Nilsson
2023-04-19 4:06 ` Hans-Peter Nilsson
2023-04-19 16:59 ` [PATCH v3] " Hans-Peter Nilsson
[not found] ` <4E63CF4D-C355-4053-8EA4-5700C1B938E3@gmail.com>
2023-04-19 20:16 ` Bernhard Reutner-Fischer
2023-04-20 2:57 ` Hans-Peter Nilsson
2023-04-26 23:55 ` Ping: " Hans-Peter Nilsson
2023-05-04 0:09 ` Hans-Peter Nilsson [this message]
2023-05-04 9:45 ` 2nd " Richard Biener
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