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Comparing Linux C and C++ Compilers
ChaoticCoyote writes "I've posted a comparison of recent GCC versions (3.3, 3.4, and the coming 4.0) with Intel C++ 8.1, including several benchmarks and "state-of-the-product" reviews. The new article replaces an older piece I published in late 2002. This
new comparison marks what I hope will be an ongoing series that tracks the quality of Linux compilers."
well, GCC has one thing going for it - it's open source - and that's why I'm sticking with it. XD
FP?
Moll.
What you hear in the ear, preach from the rooftop Matthew 10.27b
by default, gcc (with a .c or lang-spec set to c)
let's you forget the #include, and the missing return value
The current version of GCC is 3.4.2, and the next planned version will be called 4.0.0
More info on the GCC site
Even if the Intel compiler is faster, it's best not to get in the habit of becoming locked into any proprietary platform. How likely is it that features on which one could come to depend will be kept available on free platforms, much less future processors not made or controlled by Intel?
CEE5210S The signal SIGHUP was received.
This mostly comes from specializing loops and jumps. ICC does aggressive loop versioning (even including runtime CPUID checks) and, especially with profile feedback (not tested in this benchmark, unfortunately) ICC will try aggressively to try cheap alternatives before trying the generic approach. Think about expensive instructions such as divides and indirect jumpes here. GCC doesn't do that.
I hear people complain about gnu C++ alot because its not as good as commercial compilers.
However from what I see is the performance of the compiled code is the same with the exception that the resulting binaries are alot bigger.
Maybe gcc is good on x86 but sucks on other architectures? I know the Sun and SGI geeks have complained for years that gcc does not run well on their platforms compared to expensive alternatives by their vendors.
Has anyone run ICC and VC++.net on Windows? How does it compare to Borland and MS compilers under Windows2k?
http://saveie6.com/
I think the author had better mark the tests whose inner loops have been vectorized, since while some algorithms are easily vectorizable, some are not, so the performance of both are interesting. After all, we care most about the features (such as automatic vectorization) of the compiler, while benchmarks only very roughly reflect the existence of such features, the applicability of them, and their effects.
Actually there are. LCC and TinyC come to mind. They're not used much in production [well LCC was reborn as LCC-Win32 for a while] but really GCC is the better choice.
:-)
The problem with the "good old days" was that as my friend Dave Dunfield said once "C compilers are a dime a dozen".
Just because you had a dozen C compilers for your 8086 doesn't mean you were better off. In fact most compilers for the 86 were crap [e.g. smallC, byteC, Zortech, paradise, etc...]. In fact the only half-way decent 86 compilers I recall are Turbo C [v3.01 was ok] and Micro-C [by Dave Dunfield so maybe I'm a bit biased there...].
Note I'm not saying more compilers is bad. The problem is like any field "new" doesn't imply better. You have to tackle problems and answer them.
For instance, GCC is rather large and can be slow/memhog on some files [C++ in particular]. A viable competitor for Linux would be one which optimizes decently while not being such a hog. It could pitch in when you can't build a file [say from VisualBoyAdvance which requires ~1GB of ram to build with GCC 3.4.2]...
For the most part though, contributing to GCC makes more sense than writing your own compiler. First off, GCC is a "standard". So you're likely to get a huge audience that way. Second, GCC is already well established. It's a very good suite of tools and frankly hard to compete with. Third, you'll save a lot of time.
For all intents and purposes you could change your argument to why do "linux" boxes only run the Linux kernel? I mean for all intents and purposes you could write your own kernel that was interoperable and use instead. For the same reason why contributing to GCC is a good idea so is contributing to the kernel [instead of writing your own] is a good idea.
One last caveat before I send this post. I do agree though that writing such said tools [kernels or compilers in this case] are a good idea for educational purposes. It means a lot to know how to write a functional [and ideally half-way decent] compiler even if it only targets one platform and covers only part of a language.
phew...
Tom
Someday, I'll have a real sig.
You can tell this guy is a nerd, but it goes far beyond the pizza and mountain dew... Is that really an empty tub of frosting sitting my his computer??
The hostility mystifies me. I'm a semi-active participant in the GCC mailing list, and the people who work on GCC are very helpful, open, and communicative. Some even thank me for my QA efforts.
I don't see that my article is negative about GCC; in fact, I'm very clear that Intel's compiler isn't a replacement for GCC, and that GCC is a fine product. Maybe the complainers can't read?
All about me
It's called a "typo". Fixed.
All about me
The OpenBSD team use it, and I think they know better than you or I.
Not by technical choice, they want to use plan9's C compiler but have licence quibbles.
Quoting Theo : "in particular we were interested in the c compiler"
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
I find it interesting that there are only two C/C++ compilers available for Linux, as compared with seven Fortran 90/95 compilers (soon to be eight with the release of GCC 4.0). This not only dispels the myth that Fortran is a dead language, it also suggests that there is much more of a competitive market in compiling numerical code, than in producing other types of software.
Tubal-Cain smokes the white owl.
The GCC Steering Committee changed the next version of GCC from 3.5 to 4.0 while I was in the midst of writing the article. I missed changing a reference; the typo is now fixed.
All about me
TCC (tiny c compiler).
Compaq Alpha C compiler.
OpenWatcom C/C++ compiler
TenDra C/C++ compiler
egcs compiler (which merged into gcc- they saw that it had some advantages.)
ChEmbeddable
Cint c/c++ interpreter (not exactly a compiler)
CC65 Commodore C compiler
Absoft C/C++ Fortran compiler
lcc
These all run on linux. Some are open, some are not. GCC is used mainly because it is portable to just about anything-- so there goes your argument of GCC restricting choice. GCC exists to promote choice, and it does this.
Take your code written for Visual Studio and compile it on Sun. Can't do that with Visual Studio? No MFC on Sun? Your best bet will probably be good old GCC with WINE. So how are you restricted by gcc?
Now, if you want to make a cross compiler to compete with gcc- one with seperate front ends and back ends, so it can accept multiple languages, and can compile to just about every machine on earth-- then nothing is stopping you. Oh, what is that? Not interested. Neither is anyone else. Programers see no need to duplicate something that has been done well the first time. One good cross compiler is enough- GCC represents a NATURAL MONOPOLY.
...does not apply to GCC. Never has. And it will not in the future, unless we radically change the way we do development and releases.
3.4 follows 3.3 follows 3.2, and none of them were singled out as "developmental" or "experimentalal" or "extra stable". The experimental-vs-stable changes all take place before any release branch is made. There's more info on the website if you want.
You cannot apply a technological solution to a sociological problem. (Edwards' Law)
The complainers can't read. I'm a member of the GCC steering committee, and I'm very happy with Scott's work (sorry, dude, I'm not going to call you "ChaoticCoyote"). It's not perfect, but it has helped to improve GCC.
Tree-SSA is not new, it's new to GCC but the concept of Single Static Assignment itself is ancient and using it for optimizing trees in not new.
The problem is the GCC codebase is so badly designed it takes major changes to many parts to introduce a very old concept of SSA into it. So you can't take advantage of a generic SSA but have to introduce different patches for the system.
Back in my university days we did SSA in our own compilers, for a 5 week course! GCC needs a complete rewrite or a switch to something like TenDRA, which right now produces good solid code, but not extremely optimized machinecode. On the other hand TenDRA is really well designed so it would catch up really fast if more people worked on it.
This isn't true: V8.0 works fine on Athlons.