From: Frank Peters <frank.peters@comcast.net>
To: gentoo-amd64@lists.gentoo.org
Subject: Re: [gentoo-amd64] Re: GCC-4.5.2 Has Serious Problems
Date: Thu, 30 Jun 2011 22:43:07 -0400 [thread overview]
Message-ID: <20110630224307.93bf60d2.frank.peters@comcast.net> (raw)
In-Reply-To: <20110701022239.GA13184@crud>
On Thu, 30 Jun 2011 21:22:39 -0500
Barry Schwartz <chemoelectric@chemoelectric.org> wrote:
>
> C is essentially a glorified assembly language
>
IMO, that's why C is the best. It is very close to the machine
and the programmer has to be very attentive to details of hardware
as well as to software concepts.
> for bit-twiddling, which the original K&R book encouraged, and which
> this code is doing. So all is well, from my point of view. :)
Bit manipulations on integers and strings are natural. The difficulty
is with floating point variables which are not just bits but also
a complex format that does not respect byte boundaries. The ordinary bit
operators cannot apply to floating point. The only way to ordinarily get
data in/out is to use the built-in conversion routines. The language was
never designed, AFAIK, to directly manipulate floating point bits.
> Fancy
> optimizations are not to be trusted on assembly code; never be afraid
> to turn them off. You probably don’t need them, anyway. :)
>
Certainly true. But in this case, -fno-strict-aliasing is absolutely
necessary.
Also, I, as probably most others, would rather not concentrate so much
on the compiler as on the task of coding itself.
Frank Peters
next prev parent reply other threads:[~2011-07-01 2:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-30 21:45 [gentoo-amd64] GCC-4.5.2 Has Serious Problems Frank Peters
2011-06-30 22:30 ` Alex Schuster
2011-06-30 23:34 ` Frank Peters
2011-06-30 23:35 ` [gentoo-amd64] " Nikos Chantziaras
2011-06-30 23:44 ` Nikos Chantziaras
2011-07-01 0:04 ` Frank Peters
2011-07-01 0:11 ` Nikos Chantziaras
2011-07-01 0:58 ` Duncan
2011-07-01 1:23 ` Frank Peters
2011-07-01 1:52 ` Duncan
2011-07-01 2:15 ` Ian McCulloch
2011-07-01 4:36 ` Mark Knecht
2011-07-01 5:22 ` Frank Peters
2011-07-01 0:25 ` Frank Peters
2011-07-01 1:04 ` Frank Peters
2011-07-01 2:18 ` Duncan
2011-07-01 2:22 ` Barry Schwartz
2011-07-01 2:43 ` Frank Peters [this message]
2011-07-01 11:53 ` Nikos Chantziaras
2011-07-01 16:53 ` Frank Peters
-- strict thread matches above, loose matches on Subject: below --
2011-07-01 2:30 Ian McCulloch
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