Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!rutgers!cmcl2!lanl!cochiti.lanl.gov!jlg
From: jlg@cochiti.lanl.gov (Jim Giles)
Newsgroups: comp.lang.c
Subject: Re: low level optimization
Message-ID: <21436@lanl.gov>
Date: 15 Apr 91 22:26:51 GMT
References: <1991Apr9.213601.12309@agate.berkeley.edu> <1991Apr11.150858.4242@odin.diku.dk> <andand.671722866@cia.docs.uu.se>
Sender: news@lanl.gov
Organization: Los Alamos National Laboratory
Lines: 24


>>	array[index++] = something;
>> [...]
>
> That's crazy. If you want efficiency in QSort you should use
> pointer arithmetic like:
>
> 	*(pointer++) = something;  

If your compiler does something which makes the first slower than
the second, it's time to get a new compiler.  At some time in the
code you had to do something like:

      pointer = &array[1];

or even
     
      pointer = array;

The compiler should be able to perform the same operation outside
any loops and achieve the same level of optimization.  The user's
code needn't contain such things.

J. Giles