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From: bart@videovax.tv.tek.com (Bart Massey)
Newsgroups: comp.lang.perl
Subject: Re: Bugs in perl 3.0 pl 8 -- return statement
Message-ID: <5716@videovax.tv.tek.com>
Date: 14 Feb 90 22:43:43 GMT
References: <4080004@hpausla.aso.hp.com> <4080005@hpausla.aso.hp.com> <418@proexam.UUCP> <7000@jpl-devvax.JPL.NASA.GOV> <TOM.90Feb9070637@hcx2.ssd.csd.harris.com> <7068@jpl-devvax.JPL.NASA.GOV>
Reply-To: bart@videovax.tv.tek.com (Bart Massey)
Organization: Tektronix TV Measurement Systems, Beaverton OR
Lines: 33

In article <7068@jpl-devvax.JPL.NASA.GOV> lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) writes:
> Are you saying that parts of a structure
> and global variables also might get put into registers?
> 
> Actually, I can believe a super-optimizing compiler might put a global
> into a register.  I can't imagine a stucture element, tho.  I doubt
> either is your problem.

Heck, I'll say it.  Try running GCC-1.36 -O over the following C code,
and be surprised that, at least on the VAX and 68k, the structure member
ends up in a register.  Note that, at least as of 1.36, this is a very
fragile optimization, but it's bound to get nothing but better.

-----
struct foo { int a, b; };

main()
  {
    struct foo bar;

    for( bar.b = 0; bar.b < 10; bar.b++ )
        nothing( bar.b );  /* force an external reference */
  }
-----

And the brand-new DecStation 3100 (PMAX) Ultrix compiler does global
register optimizations, or so I am told.

Aren't compilers wonderful?

					Bart Massey
					..tektronix!videovax.tv.tek.com!bart
					..tektronix!reed.bitnet!bart