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Thu, 21 Apr 2016 09:35:21 -0700 (PDT) X-Received: by 10.25.82.203 with SMTP id g194mr7128614lfb.1.1461256521002; Thu, 21 Apr 2016 09:35:21 -0700 (PDT) MIME-Version: 1.0 Received: by 10.25.85.5 with HTTP; Thu, 21 Apr 2016 09:35:01 -0700 (PDT) In-Reply-To: <9213202F68854BA7A7A9CF9179DF685E@erratique.ch> References: <9213202F68854BA7A7A9CF9179DF685E@erratique.ch> From:Ben Millwood Date: Thu, 21 Apr 2016 12:35:01 -0400 Message-ID: To:=?UTF-8?Q?Daniel_B=C3=BCnzli?= Cc:Gabriel Scherer , Gregory Malecha , Yaron Minsky , Jonas Jensen , caml users Content-Type: multipart/alternative; boundary=001a1141d984dc546d0531014b37 X-JS-Processed-by: mailcore X-Sender-Copy: hkg-copy Subject: Re: [Caml-list] Question about Optimization --001a1141d984dc546d0531014b37 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable You can see hints at the problems with rewrite rules by reading about the mechanisms GHC has to work around them: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/pragmas.htm= l#inline-pragma For example, rules can be prevented from matching if some subexpression is inlined first, but on the flipside, some rules need some inlining to occur before they can match. This leads GHC to support "phase specifications" that help you to control the order of inlinings and rules. On 21 April 2016 at 12:05, Daniel B=C3=BCnzli wrote: > Le jeudi, 21 avril 2016 =C3=A0 18:02, Gabriel Scherer a =C3=A9crit : > > useful in some situations but also very fragile. > > What kind of fragility ? > > Daniel > > > > -- > Caml-list mailing list. Subscription management and archives: > https://sympa.inria.fr/sympa/arc/caml-list > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > Bug reports: http://caml.inria.fr/bin/caml-bugs > --001a1141d984dc546d0531014b37 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
You can see hints at the problems with rewrite rules = by reading about the mechanisms GHC has to work around them:

=
For example, rules can be prevented from matching if some subexpres= sion is inlined first, but on the flipside, some rules need some inlining t= o occur before they can match. This leads GHC to support "phase specif= ications" that help you to control the order of inlinings and rules.

On 21 April 2= 016 at 12:05, Daniel B=C3=BCnzli <daniel.buenzli@erratique.ch> wrote:
Le j= eudi, 21 avril 2016 =C3=A0 18:02, Gabriel Scherer a =C3=A9crit :
> useful in some situations but also very fragile.

What kind of fragility ?

Daniel



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