Path: utzoo!mnetor!uunet!husc6!bloom-beacon!think!ames!eos!aurora!labrea!decwrl!hplabs!hpcea!hpfcdc!hpfclq!mike
From: mike@hpfclq.HP.COM (Mike McNelly)
Newsgroups: comp.lang.c
Subject: Re: I forget what it was originally called.
Message-ID: <3850010@hpfclq.HP.COM>
Date: 7 Mar 88 16:21:36 GMT
References: <3505@bloom-beacon.MIT.EDU>
Organization: Hewlett-Packard
Lines: 19

Not only do different types cause changes in the order of evaluation,
but different classes may also cause differences.  C compilers make
choices on the order of evaluation based on the "cost" of evaluating a
subexpression.  Pcc compilers typically evaluate a a subexpression with
a high cost in register resources first.

As a specific example, you may find your expression compiled differently
if "i" is declared to be a register variable than if it was an auto or a
static.

Frankly I have little sympathy with anyone writing code in this manner.
It's cute but it's also no more efficient than alternatives that do what
you really wanted to do in a much less ambiguous fashion.  If you
inherited this code you have my condolences.



Mike McNelly
hplabs!hpfcla!mike