Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Programming > C Programming > Most portable compiler: llvl llc or pcc or gcc rtl?

Reply
Thread Tools

Most portable compiler: llvl llc or pcc or gcc rtl?

 
 
Keith Thompson
Guest
Posts: n/a
 
      10-11-2012
David Brown <(E-Mail Removed)> writes:
> On 11/10/2012 15:45, jacob navia wrote:

[...]
>> Yes. In general, Microsoft compilers outperform gcc by a wide margin

>
> Microsoft's compilers under-perform compared to almost any realistic C
> compiler, because they don't support modern C.


I agree that Microsoft's failure to support C past the 1990 standard is
a problem, but it's not a performance issue.

[...]

--
Keith Thompson (The_Other_Keith) http://www.velocityreviews.com/forums/(E-Mail Removed) <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
 
Reply With Quote
 
 
 
 
88888 Dihedral
Guest
Posts: n/a
 
      10-15-2012
On Thursday, October 11, 2012 5:58:45 PM UTC+8, Ir. Hj. Othman bin Hj. Ahmad wrote:
> On Oct 10, 2:08*am, jacob navia <(E-Mail Removed)> wrote:
>
> > Le 09/10/12 19:05, Walter Banks a crit :

>
> >

>
> >

>
> >

>
> > > "Ir. Hj. Othman bin Hj. Ahmad" wrote:

>
> >

>
> > >> My bet is in llc. I shall try to produce a PIC 16 code generator.

>
> >

>
> > > I have written two PIC 16 C compilers. It is not a trivial undertaking.

>
> >

>
> > > Walter Banks

>
> > > Byte Craft Limited

>
> >

>
> > You can say that because you know what you are talking about: you have

>
> > written two PIC 16 C compilers.

>
> >

>
> > He hasn't, so he thinks it is easy, just filling in the blanks in some

>
> > portable C compiler.

>
> >

>
> > As if you could translate from a preemptive 32/64 bit architecture to a

>
> > PIC 16 without rewriting everything.

>
>
>
> There are examples such as avr and dsps as guides. Lots of
>
> documentations to follow and learn.
>
> To get a good job is equivalent to a MSc thesis, because some of them
>
> did it for their thesis.
>
>
>
> However, I am only interested to do the basics, just as limiting the
>
> data types to just a few.
>
> If I can get some form assembler sources, it will be enough.
>
> The first stage is just to compile and generate cross assemblies
>
> first.
>
>
>
> I have got a feeling that current compilers are getting portable. They
>
> just need more documentatiions to enable people
>
> to port to many architectures. The techniques can be improved further.
>
> Instead of just for speed, we can optimise for
>
> portablility. Just like the old pcc, and now resurrected.
>
>
>
>
>
> >

>
> > In general I have found that most open source code compilers are just

>
> > too bulky for small machines, much too full of hidden assumptions for

>
> > cramped environments.

>
>
>
> It may be bulky but machines are so fast, they become so
>
> insignificant. We are working with Terabytes now.
>
>
>
> >

>
> > Even lcc was too big when I ported it to an analog devices 16 bit DSP,

>
> > and that was a machine that wasn't at all as difficult as the PIC 16!

>
> >

>
> > jacob


Well, for those critical heavy processing parts in C,
I'll consider to transform some parts into assemblies of the native
hardware platforms if I could be paid well.

I think this is the spirit of turning non-commercial projects
into commercial projects.
 
Reply With Quote
 
 
 
 
88888 Dihedral
Guest
Posts: n/a
 
      10-19-2012
David Brown於 2012年10月11日星期四UTC+8下午11時06分08 寫道:
> On 11/10/2012 15:45, jacob navia wrote:
>
> > Le 11/10/12 15:20, Ir. Hj. Othman bin Hj. Ahmad a �crit :

>
> >

>
> >> Is there any commercial C compilers that can overcome significantly

>
> >> gcc? When even apple has gone the gcc approach.

>
> >>

>
>
>
> I thought Apple used llvm rather than gcc - but I could be wrong.
>
>
>
> >

>
> > Yes. In general, Microsoft compilers outperform gcc by a wide margin

>
>
>
> Microsoft's compilers under-perform compared to almost any realistic C
>
> compiler, because they don't support modern C.
>
>
>
> A quick google does not show any evidence for your claim - it shows a
>
> mixed bag of results depending on who tested, what code was tested, what
>
> versions were used, etc. From my very unscientific survey, it looks
>
> like the bias is that MSVC generates slightly faster code than gcc.
>
>
>
> >

>
> > And Intel's compilers outperform Microsoft's by a wide margin too

>
> >

>
>
>
> Again, I can find no evidence for such claims.
>
>
>
> It seems to be the case that Intel's compiler can generate better SIMD
>
> code automatically than gcc can, so for code that benefits greatly from
>
> SIMD (but which does not have explicit SIMD code) will get a big boost.
>
> Other than that, it appears that Intel's code is a bit faster than gcc's.
>
>
>
> Of course, MSVC is restricted to windows, and Intel's compiler is
>
> heavily tuned for Intel processors (though obviously it supports other
>
> x86/amd64 chips) - while gcc and llvm support a wide range of targets
>
> and hosts.
>
>
>
> The most comprehensive benchmark I have seen is this one:
>
>
>
> <http://www.willus.com/ccomp_benchmark2.shtml?p18+s14>
>
>
>
> That puts gcc 4.6 at 18% behind Intel, and MSVC at 24% behind.
>
>
>
> But of course benchmarks are never absolute unless /you/ run them on
>
> /your/ system using /your/ code.


In my experience of C compilations of programs I always test
the followings :

1. malloc, memcpy, memset for different block sizes
2. compute sums of int, float, and double arrays in the pointer version
and the array version for differences in speeds of executions

3. calling methods customizable to use and link
with object libraries in basic, fortran pascal, lisp and etc..

4. assembly embedding

5. testing for unbuffered-buffered I/O in peripheral device drivers

Most of these are not related to language issues but man-years spend
in the the c compiler to be fine-tuned to work with the
specific os and the matched hardware platform.




 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Compiling pcc in cygwin Ir. Hj. Othman bin Hj. Ahmad C Programming 0 10-11-2012 09:48 AM
NovelSpace Media, LLC announces the launch of their new online bookstore and web portal devoted to developers and programmers. paquejd@gmail.com Java 0 05-13-2006 07:04 PM
Novosoft Inc, Novosoft LLC and Softlogica LLC Morgan Pugh Computer Support 5 04-18-2005 08:31 PM
Blue Digits LLC releases VM Rover - Universal Voicemail Client Blue Digits VOIP 1 03-07-2005 06:09 AM
muti printer use fron one PCc Piemanlager Digital Photography 3 03-02-2005 05:35 AM



Advertisments