Path: utzoo!mnetor!uunet!husc6!bloom-beacon!athena.mit.edu!wesommer
From: wesommer@athena.mit.edu (William E. Sommerfeld)
Newsgroups: comp.lang.c++
Subject: Re: QUESTIONS, QUESTIONS.
Message-ID: <2643@bloom-beacon.MIT.EDU>
Date: 29 Jan 88 14:56:26 GMT
References: <731@entropy.ms.washington.edu>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: wesommer@athena.mit.edu (William E. Sommerfeld)
Organization: Massachusetts Institute of Technology
Lines: 20

In article <731@entropy.ms.washington.edu> vonn@entropy.UUCP (Vonn Marsch) writes:
>1. Most LISP compilers know to compile tail-recursive functions
>   as iteration.  Are most c++ preprocessors this smart?

The GNU C compiler (and, presumably, the GNU C++ compiler, since
they're based on the same code generator and optimizer) special-case
self-tail-recursion.  This is probably because Stallman has a strong
background of work on LISP systems and LISP compilers.  Interestingly
enough, GCC uses a fair amount of tail recursion internally;
GCC-compiled-with-GCC uses noticeably less stack space than if
compiled with other compilers.

So, if you use the AT&T C++->C compiler with GCC, or GNU C++, you wind
up with a compiler which knows how to deal efficiently with tail
recursion.

Note that GCC is very much in beta test, and GNU C++ is very much in
alpha test.

					- Bill