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Path: utzoo!linus!decvax!harpo!eagle!allegra!alice!rabbit!mjs
From: mjs@rabbit.UUCP
Newsgroups: net.lang.c
Subject: Re: Must useless expressions be evaluated?
Message-ID: <2060@rabbit.UUCP>
Date: Thu, 13-Oct-83 18:44:33 EDT
Article-I.D.: rabbit.2060
Posted: Thu Oct 13 18:44:33 1983
Date-Received: Fri, 14-Oct-83 20:07:18 EDT
References: <187@bbncca.ARPA>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 12

Various optimizers will detect `dead' scratch registers & delete the
assembly language which generates the value (if the assembly code has
no other side effects, such as auto-incrementing a different
register).  I'm not certain if the current /lib/c2 for the VAX does
this, but it should.  Yes, I suppose it would be nice if the compiler
didn't generate such code in the first place, and my guess is that it
would be completely legitimate for it to do so, however, I don't
believe that PCC can easily be made to do this.
-- 
	Marty Shannon
UUCP:	{alice,rabbit,research}!mjs
Phone:	201-582-3199