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From: jfr@locus.com (Jon Rosen)
Newsgroups: comp.lang.misc
Subject: Re: Fortran vs. C for numerical work
Message-ID: <20467@oolong.la.locus.com>
Date: 11 Dec 90 14:53:22 GMT
References: <13552@chaph.usc.edu> <1990Dec10.070017.19821@actrix.gen.nz> <13585@chaph.usc.edu>
Organization: Locus Computing Corp, Los Angeles
Lines: 23

In article <13585@chaph.usc.edu> jeenglis@alcor.usc.edu (Joe English Muffin) writes:
>Bruce.Hoult@bbs.actrix.gen.nz writes:
>
>>>>In C or Pascal you could allocate a structure as a global (static) variable,
>>>                                                    ^^^^^^^^^^^^^^
>>>To allow recursion, the compiler would have to allocate this
>>>as 'auto,' in the caller's stack frame.
>
><stuff deleted> 
>
>It's very difficult for the compiler to determine
>that there's no recursion going on.  ...  

Ah... it should be noted that PL/I (an often denigrated but in many ways
superior language to both FORTRAN and C) solves this problem quite neatly...
Routines may be declared RECURSIVE in which case automatic variables are
allocated as part of a "frame" along with the appropriate register save
areas.  Any routine not so declared may not be used recursively and only
one copy of local variables is created.  This permits increased optimization
by the compiler and also reduces performance degradation due to reallocation
of local variables.
 
Jon Rosen