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Re: gEDA-user: Icarus Verilog building from CVS
Well, I am running some computationally intensive code, ( CFD ), and gcc 3.5 ( upcoming ) is giving a boost of up to 30 % for FORTRAN and C code in some instances.
The 'new' gcc does have a much better optimization framework, and it is really starting to show, it should fx. be able to run head to head with intels compiler provided that it is supplied with a reasonable set of compiler flags, ( which is an area of itself :-) ).
SO if you look for the code generated by the 'state of the art' gcc i do not believe your statement to be true, ( check out code for the sh and h8 processors or the mips32 instruction set ).
If you have any cases which can be reduced to misoptimizations please post a bug report on gcc.gnu.org
If not, ( and from my opinion and experience ), I can only conider your statement an ill informed opinion.
( btw. dec's compiler used to build on gcc :-) especially the openMP part ), and this should give some indication of the performance of gcc.
The big thing I have against the beast is it's compilatioon speed and memory requirements, it's slow and big.
/ best regards, Lars Segerlund.
On Sat, 7 Aug 2004 00:07:51 -0400
Dave McGuire <firstname.lastname@example.org> wrote:
> On Aug 6, 2004, at 11:44 PM, Al Davis wrote:
> >> Despite its popularity in the x86 world, GCC generates
> >> horrid code on most, if not all, modern RISC platforms. The
> >> vendor-supplied compilers represent a tremendous amount of
> >> in-the-know optimization and well-funded development that is
> >> specific to their processor architectures.
> > Really????
> Really. :)
> > A few years ago, when I had access to a bunch of machines and a
> > bunch of compilers I tried ACS (precursor to Gnucap) on all of
> > them, with both GCC and the native one if possible. The only
> > one that had any significant difference was Sun's. The Sun
> > compiler was about 20% slower than GCC. Has Sun's compiler
> > improved that much, or has GCC gotten that much worse? Perhaps
> > Sun's compiler is better in some cases, and GCC better in
> > others?
> That's certainly possible. I have enough data points, however, that
> I don't even bother to install GCC on my Solaris systems anymore.
> Now bear in mind, this is coming from a long-time GCC lover. Back In
> The Day(tm), I remember the very first thing to do on any new VAX
> system (running either VMS or UNIX) was to install GCC because it
> generated code that was much faster. The same went for M68K-based
> Suns...GCC produced much, much faster executables than the
> vendor-supplied compiler. That said, however, M68K and VAX are
> *extremely* CISC processors, designed to support compilers from the
> ground up. GCC's initial development was on processors like
> that...Very CISC architectures, and that's where it really seems to
> shine, even today.
> (except, of course, for all the non-standard crap that it allows that
> many people unknowingly or uncaringly use, resulting in nonportable
> But try it on a MIPS, SPARC, or other modern RISC or post-RISC
> architecture and things don't look so good. I've not done extensive
> reading on this, but I'm told that the inclusion of IBM's Haifa
> instruction scheduler in GCC a few years ago helped matters for RISC
> architectures, but the situation still gives me that "not so fresh"
> > Having said that... Looking at the assembly code for C++, I see
> > that they are still missing some significant optimizations that
> > are not possible in C.
> Hmm. I'm not much into C++ (I'm a C guy) so I can't speak to that.
> I'd love to see some examples though.
> Dave McGuire "...it's a matter of how tightly
> Cape Coral, FL you pull the zip-tie." -Nadine Miller