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From: bright@dataio.UUCP (Walter Bright)
Newsgroups: net.lang.c
Subject: Re: C programming style
Message-ID: <723@dataio.UUCP>
Date: Mon, 22-Jul-85 05:51:11 EDT
Article-I.D.: dataio.723
Posted: Mon Jul 22 05:51:11 1985
Date-Received: Thu, 25-Jul-85 08:11:53 EDT
Reply-To: bright@dataio.UUCP (Walter Bright)
Organization: Data I/O Corp., Redmond WA
Lines: 16

>In article <186@drivax.UUCP> braun@drivax.UUCP (Karl Braun) writes:
>The comment regarding the efficiency of the
>produced code is probably applicable to most compilers, but academically, any
>reasonable optimizer should optimize 'i = i + 1' to equivalant code.  

Most Pascal and Fortran compilers will replace i=i+1 with i+=1 internally.
C compilers, however, usually don't bother because the i+=1 and ++i forms
are available, and the assumption is that they would have been used. These
comments also apply to all the op= forms in C.

Some C compiler trivia:
Since (i+=1) is exactly equivalent to (++i), most C compilers immediately
translate (++i) into (i+=1), and internally use the second one from then
on. Also, (i++) is usually internally translated to (i+=1) if the result
of the expression is not used. These kinds of conversions make life
easier for the code generator.