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 <[EMAIL PROTECTED]> 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 > code) > > 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" > feeling. > > > 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 > > -- > Dave McGuire "...it's a matter of how tightly > Cape Coral, FL you pull the zip-tie." -Nadine Miller >
