Path: csiph.com!usenet.pasdenom.info!aioe.org!news.stack.nl!newsfeed.xs4all.nl!newsfeed3a.news.xs4all.nl!xs4all!post.news.xs4all.nl!not-for-mail
Return-Path: <python-python-list@m.gmane.org>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.002
X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'cpython': 0.05; '(b)': 0.07; 'variables': 0.07; 'received:80.91': 0.09; 'received:80.91.229': 0.09; 'received:gmane.org': 0.09; 'received:list': 0.09; 'subject:Does': 0.09; 'python': 0.11; 'def': 0.12; 'article:': 0.16; 'received:80.91.229.3': 0.16; 'received:dip0.t-ipconnect.de': 0.16; 'received:plane.gmane.org': 0.16; 'received:t-ipconnect.de': 0.16; 'subject:already': 0.16; 'url:file': 0.16; 'wrote:': 0.18; 'all,': 0.19; 'feb': 0.22; '>>>': 0.22; 'import': 0.22; 'header:User-Agent:1': 0.23; '(a)': 0.24; 'byte': 0.24; 'header:X-Complaints-To:1': 0.27; '(c)': 0.29; 'skip:( 20': 0.30; 'code': 0.31; 'linux': 0.33; 'url:python': 0.33; 'there': 0.35; 'subject:?': 0.36; 'url:org': 0.36; 'to:addr :python-list': 0.38; 'to:addr:python.org': 0.39; 'received:org': 0.40; 'skip:u 10': 0.60; 'read': 0.60; 'kind': 0.63; 'more': 0.64; 'temporary': 0.65; 'url:c': 0.67; '2014,': 0.84; 'subject:skip:o 10': 0.84; 'url:cpython': 0.84
X-Injected-Via-Gmane: http://gmane.org/
To: python-list@python.org
From: Peter Otten <__peter__@web.de>
Subject: Re: Does CPython already has Peephole optimizations?
Date: Mon, 17 Feb 2014 09:45:47 +0100
Organization: None
References: <CAFtnWG9Zm75mQY--54mYMyHvNhhanr51VBjRDMK4xMoo_AaxNQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7Bit
X-Gmane-NNTP-Posting-Host: p57bdb5c1.dip0.t-ipconnect.de
User-Agent: KNode/4.7.3
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list/>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.7087.1392626746.18130.python-list@python.org>
Lines: 42
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1392626746 news.xs4all.nl 2915 [2001:888:2000:d::a6]:45480
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:66595

Laxmikant Chitare wrote:

> Hello All,
> 
> I read about this article:
> 
http://www.python.org/workshops/1998-11/proceedings/papers/montanaro/montanaro.html
> 
> Just wanted to clarify whether CPython already includes these kind of byte
> code optimizations? Are all the temporary variables removed when byte code
> is generated?

You can find out for yourself:

Python 3.4.0rc1+ (default:2ba583191550+, Feb 12 2014, 00:08:44) 
[GCC 4.6.1] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import dis
>>> def f():
...     a, b, c = 1, 2, 3
... 
>>> dis.dis(f)
  2           0 LOAD_CONST               4 ((1, 2, 3))
              3 UNPACK_SEQUENCE          3
              6 STORE_FAST               0 (a)
              9 STORE_FAST               1 (b)
             12 STORE_FAST               2 (c)
             15 LOAD_CONST               0 (None)
             18 RETURN_VALUE
>>> def g():
...     q = 2 + 3j
... 
>>> dis.dis(g)
  2           0 LOAD_CONST               3 ((2+3j))
              3 STORE_FAST               0 (q)
              6 LOAD_CONST               0 (None)
              9 RETURN_VALUE

If you can read C there is also

http://hg.python.org/cpython/file/180e4b678003/Python/peephole.c