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GCC 3.3 Released
devphil writes "The latest version of everyone's favorite compiler, GCC 3.3, was released today. New features, bugfixes, and whatnot, are all available off the linked-to page. (Mirrors already have the tarballs.) Let the second-guessing begin!"
mmm i'll install this one only cuz it rhymes ;)
Well, fire up your computers gentelmen.....
The lunatic is in my head
just for information re-compiling glibc 2.3.2 with gcc 3.3 fails. i don't see the point releasing a compiler or standard glibc which doesn't allow the existing compiler to be used to compile it.
Congratulations, so many bugs fixed, cool!
I wonder ow much slower than the last release is it...
Yooo hoooo.... I could post anything and be the first... All the beowulf cluster of those, soviet russia, and even start a flame war of GCC vs something else. Sorry, just trolling in here
__________
Don't belong. Never join. Think for yourself. Peace!
yay
Caveats
The preprocessor no longer accepts multi-line string literals. They were deprecated in 3.0, 3.1, and 3.2.
The preprocessor no longer supports the -A- switch when appearing alone. -A- followed by an assertion is still supported.
Support for all the systems obsoleted in GCC 3.1 has been removed from GCC 3.3. See below for a list of systems which are obsoleted in this release.
Checking for null format arguments has been decoupled from the rest of the format checking mechanism. Programs which use the format attribute may regain this functionality by using the new nonnull function attribute. Note that all functions for which GCC has a built-in format attribute, an appropriate built-in nonnull attribute is also applied.
The DWARF (version 1) debugging format has been deprecated and will be removed in a future version of GCC. Version 2 of the DWARF debugging format will continue to be supported for the foreseeable future.
The C and Objective-C compilers no longer accept the "Naming Types" extension (typedef foo = bar); it was already unavailable in C++. Code which uses it will need to be changed to use the "typeof" extension instead: typedef typeof(bar) foo. (We have removed this extension without a period of deprecation because it has caused the compiler to crash since version 3.0 and no one noticed until very recently. Thus we conclude it is not in widespread use.)
The -traditional C compiler option has been removed. It was deprecated in 3.1 and 3.2. (Traditional preprocessing remains available.) The header, used for writing variadic functions in traditional C, still exists but will produce an error message if used.
General Optimizer Improvements
A new scheme for accurately describing processor pipelines, the DFA scheduler, has been added.
Pavel Nejedly, Charles University Prague, has contributed new file format used by the edge coverage profiler (-fprofile-arcs).
The new format is robust and diagnoses common mistakes where profiles from different versions (or compilations) of the program are combined resulting in nonsensical profiles and slow code to produced with profile feedback. Additionally this format allows extra data to be gathered. Currently, overall statistics are produced helping optimizers to identify hot spots of a program globally replacing the old intra-procedural scheme and resulting in better code. Note that the gcov tool from older GCC versions will not be able to parse the profiles generated by GCC 3.3 and vice versa.
Jan Hubicka, SuSE Labs, has contributed a new superblock formation pass enabled using -ftracer. This pass simplifies the control flow of functions allowing other optimizations to do better job.
He also contributed the function reordering pass (-freorder-functions) to optimize function placement using profile feedback.
New Languages and Language specific improvements
C/ObjC/C++
The preprocessor now accepts directives within macro arguments. It processes them just as if they had not been within macro arguments.
The separate ISO and traditional preprocessors have been completely removed. The front-end handles either type of preprocessed output if necessary.
In C99 mode preprocessor arithmetic is done in the precision of the target's intmax_t, as required by that standard.
The preprocessor can now copy comments inside macros to the output file when the macro is expanded. This feature, enabled using the -CC option, is intended for use by applications which place metadata or directives inside comments, such as lint.
The method of constructing the list of directories to be searched for header files has been revised. If a directory named by a -I option is a standard system include directory, the option is ignored to ensure that the default search order for system directories and the special treatment of system header files are not defeated.
A few more ISO C99 features now work correctly.
A new function attribute, nonnull, has been added which allows pointer arguments to functions to be specified as requiring
My favorite programming language is English.
Wank it at SmoothPorn.
And "cant compile kernel with gcc 3.3" messages started to appear on lkml. Is it me or gcc team goes for quantity rather than quality that they even postponed many bugs ( like c++ compile time regression ) to gcc 3.4 to release 3.3...
Never learn by your mistakes, if you do you may never dare to try again
I hear they have added in some more advanced, and aggressive bounds checking. Now when i screw up something i wont have to wait for a seg-v to tell me that pointer moved a little too far.
Although it dosnt seem to work with glibc....this is quite annyoing, although it probably will be fixed and re-released in a few days
Or as is said in "The Gold Coast", if you've got land and you've got money, you gotta build.
Logic, macros, and more
..but when will Linux get a decent IDE?
This is why I stick to coding for Win32 - Visual Studio is an absolute joy to use.
Windows - developer friendly. Linux - developer hostile.
I'm waiting for SCO to show it's copied code before I pick up any GNU software.
-... ---
I believe this version has stricter checking. It is probably a good idea for everyone with programs out there to do a quick recompile and see if there is something you can improve or error messages you can fix.
If you think deeply enough, you will have no single direction for your outrage.
is that Fyodor is a wanker!
Oh no, is he going to savagely root my box and post gay porn that he says he got off my computer?
Does this release break binary compatibility?
The optimiser has been vastly improved and ....
The following changes have been made to the IA-32/x86-64 port:
SSE2 and 3dNOW! intrinsics are now supported.
Support for thread local storage has been added to the IA-32 and x86-64 ports.
The x86-64 port has been significantly improved.
If you wan't compile time performance look at
Precompiled Headers
thank God the internet isn't a human right.
You DO realize that most of the problems compiling the Linux kernel with succeeding releases of gcc is due primarily to the kernel team making incorrect assumptions about the kernel output...
Right?
[ home ]
Yes, this release (like all 3.x releases) is a lot slower than 2.9x was. This is particularly true for C++, to the point where the compile-time cost of standard features like iostreams or STL is prohibitive on older, slower machines. I've largely gone back to stdio.h and hand-rolled containers for writing non-production code, just to keep the edit-compile-test cycle ticking along at a decent pace.
The new support for precompiled headers will help to some extent but is by no means a panacea. There are a lot of restrictions and caveats. The good news is that the GCC team are very well aware of the compile-time issue and (according to extensive discussions on the mailing list a few weeks back) will be making it a high priority for the next (3.4) release.
Incidentally, for those wanting a nice free-beer-and-speech IDE to use with this, the first meaningful release of the Eclipse CDT is at release-candidate stage and is looking good.
In other words, if you don't have some special reason (developer, tester, guru, itch up the arse) to try it, don't. The newbs often rush in to try a new sparkly piece of software just because. But when that particular piece of is a compiler, you're better off waiting a few months until software projects mantainers pick up on the changes.
The new breed of gcc compiler are anywhere from 3 %to 5% slower with file processing using the C++ library. So, compiling the kernel with gcc 3.x is fine, but I suspect that something like KDE which is mostly written in C++ is impacted seriously. At least, all software using the C++ library for IO (fstream) will be much slower. On the other hand, the support for C++ standards is much better so what I do is that I compile using gcc 3.2.3 to validate my C++ and then I run the real thing with a pre 3.x compiler.
You write your own containers because STL compiles
too slow?! I guess you don't value your time AT ALL.
Vax VMS has been obsoleted!
That's great... but can anyone tell us what a difference all that will make? I don't really care about compile times (too much)... but will mpeg2enc or ffmpeg run faster?
BTW, there is a preliminary ebuild in Gentoo.
http://blog.grcm.net/
According to this, if your program is multi-threaded, uses spinlocks in libstdc++, and runs on x86, then you'll have to configure gcc-3.3 for a i486+ target (instead of i386) in order to make it binary compatible with gcc-3.2.x configured for a i386 target. Otherwise when the code is mixed, the bus isn't locked when accessing the spinlock, which IMHO may cause concurrency problems on SMP boxes (?)
GCC is "everyone [sic] favorite compiler" just like Windows is everyone's favorite operating system.
...the Installsheild Windows binaries are nowhere to be found. Sigh....
Not for me, thanks. I prefer the dynamic duo of Borland's C++ Builder/Kylix. Cross platform gui development? How you say...ah yes...w00t!
For Java, Sun One Studio (crappy name)/Netbeans (inaccurate name) floats my boat. There is a light C++ module for Netbeans but I haven't tried it...no need.
Give Kylix a try - there is a free version you know:
Borland® Kylix(TM) 3 Open Edition delivers an integrated ANSI/ISO C++ and Delphi(TM) language solution for building powerful open-source applications for Linux,® licensed under the GNU General Public License
Download it here.
They don't really seem to care about not following the standard for i686. You still have to compile everything for i586 on the Via C3 Ezra chips. The specs. for i686 states that cmov is an optional feature in i686 chips but gcc still doesn't check if the cpu supports it. Of cause with the new C3 it doesn't matter, but I don't have one of those.
Not a big fault, but it would be nice not having to remember to set the cpu type to i586 everytime you compile stuff.
What's a 2.0 gig barebones box cost now? $400?
How cheap do you work for that you can't afford a $400 tool that would free you to use ANSI and ISO standard code that you don't have to develop and debug?!?!?
or maybe $249 yen, $249 francs?
> Indicators, they are your friends! >
If performance is important, do this:
int fd;
struct stat sb;
void *data;
fd = open(...);
fstat( fd, &sb );
data = mmap( NULL, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0 );
close( fd );
munmap( data, sb.st_size );
This will out-perform damn near anything.
Seems useful, though I suspect many derefernced pointers are set NULL at runtime, and so not spottable during build.
Note: I didn't change the wording above at the [sic], but I believe that this should read "all pointer arguments" instead.
sig is
To install I had to boot a single-processor kernel.
Seems to be a kernel bug in the wait4() code. If I had the time to run down all the things kernel.org wants for a bug report I'd report it. But I'm using Sun One to generate paychecks right now...
Let me guess. The -1 flamebait moderator is a Windows fan, right?
Intel's compiler smokes gcc in most benchmarks (not surprising, given that Intel knows how to squeeze every last bit of performance out of their own processors). Although it is not 100% compatible with all the gcc features, and therefore can't compile the Linux kernel, each release adds more and more compatibility. I hope the day will soon come when we can compile a whole Linux distribution with the Intel compiler.
gcc compiles code for umpteen different architectures, not just pentium and itanic. If the gcc people concentrated on one or two processors I'm sure they could get it to produce faster code too.
Give it up, Ballmer! You're not fooling anyone.
As for the mmap option... IMHO it is a little bit complicated, and glibc seems to use mmap on read-only streams anyway.
that open source requires more skill on the part of the developer to get through the learning curve.
A greater amount of knowledge about what is happening at all levels is mandatory to make that GNU\Linux system happen.
Whether this is a but or feature probably depends on your current location on the learning curve. The more I interact with open source, the more I like the fact that there are relatively fewer secrets about what is occuring, a feature that seems lost by the time you reach the West Coast...
Get thee glass eyes, and, like a scurvy politician, seem to see things thou dost not.--King Lear
Treating casts as lvalues is a GCC extension, and an extension that has been deprecated for C++ since 3.0 because it causes problems for valid C++ code.
I believe the plan is to add a warning in 3.4 and remove it in 3.5.
Well, at least I feel good because I took the right topic
The inline flag in C and C++ is a hint to the compiler that inlining this function is a good idea, just like register is a hint to the compiler.
GCC has always treated inline as such a hint, but the heuristics of how to use the hint has changed, so some functions that used to be inlined no longer is inlined.
The kernel has some function that *must* be inlined, not for speed but for correctness. GCC provide a difference way to specify this, a "inline this function or die" flag. Development kernels use this flag.
Does amazing thing for correctness, and is much easier to understand. However, it is not faster in general. It is faster at some tasks and slower at others, same on average.
It also exposes tons of errors in existing C++ programs, so expect lots of whining when GCC 3.4 is released.
GCC 3.4 will have precompiled headers (thanks Apple), which will speed compilation up a lot for project that uses them.
OK, I'm not a developer. I don't write code--I compile it when the tools I need as an admin aren't available as trusted binaries.
Why, for the love of god, is there a new version of the de facto standard C compiler every week or two? Why can't binary compatability be maintained? WHAT sort of changes and development occur in the land of compiling a language that (as far as I know) isn't changing??!!
This isn't a rant--these are serious questions. I don't understand why so many changes are being done to a compiler, and why it should affect me as a non-developer. What am I missing here?
"People who do stupid things with hazardous materials often die." -- Jim Davidson on alt.folklore.urban
The C and Objective-C compilers no longer accept the "Naming Types" extension (typedef foo = bar); it was already unavailable in C++. Code which uses it will need to be changed to use the "typeof" extension instead: typedef typeof(bar) foo. (We have removed this extension without a period of deprecation because it has caused the compiler to crash since version 3.0 and no one noticed until very recently. Thus we conclude it is not in widespread use.)
Or rather, gcc version >= 3.0 is not in widespread use.
A lot of code will use fstream read and write.
That's the standard way to do things. Granted,
that's not high performance programming... but
that's common programming. If 90% of C++ code out there is slowed down by at least a fixed percentage, this will have a major impact.
I agree that Visual Studio is a pretty decent IDE. I've used it for years and have grown to love it.
However, after using Eclipse, I'm never going back (except if I need a good Win32 GUI resource editor).
I could almost swear I typed 30%, not 85%... sorry for any confusion.
And yes, all statistics courtesy of Flagrant Estimation Incorporated.
Cut that out, or I will ship you to Norilsk in a box.
That's a gcc extension? I've been using that in my code for years! Of course, all my code is compiled on gcc... Code like this:
*(unsigned int *)(voidpointer) = intval;
isn't valid C/C++? Or do you mean gcc allows something like this:
(unsigned char)(longval) = charval;
?
A solution to the problem with music today
They do exist - and gcc pretty much can't use them.
Okay, while libc and gcc are technically different projects, as I understand it, I agree that it would seem reasonable to drop a note to the libc folks saying "hey, gcc can't compile libc" and waiting for an update before releasing.
On the other hand, the argument that the gcc folks should make sure that the *kernel* (presumably the Linux kernel) compiles is absolutely ridiculous. The kernel has been long broken and not language-compliant. I think recent compilers can compile it, but that's very recent, and hardly the fault of the gcc people. The Linux kernel has no association with gcc, and is not an amazingly clean project. Gcc is used in far more places than Linux is -- on just about every OS and architecture in the world. Blocking a gcc release because the Linux kernel doesn't compile would be insane. Gcc is *far* bigger than Linux. It is the standard available-everywhere compiler.
When someone misuses English, do you correct them or change the entire language to fit their mistake?
It's great to hear about all these new improvements in gcc, but what I really want is a working debugger for C++ code compiled with gcc. The gdb debugger is buggy as all hell. It gives wrong values for variables, has no end of troubles with C++, and often enough when I want to print out the value of a variable it tells me that it can't access that memory, with no further explanation.
Stallman controls GNU.
GNU controls GCC.
Stallman hates closed-source software.
Closed source software can only be distributed as binaries.
Binaries are a PITA when the ABI changes.
People tend to avoid things that are a PITA.
GCC frequently produces new and incompatible ABIs.
> *(unsigned int *)(voidpointer) = intval;
I don't think that code has a problem, the "*" operator uses an rvalue, so you don't actually use the lvalue of the cast.
If you had written
(unsigned int *)(voidpointer) =
I believe you would have been in extension territory.
I am a windows developer and we use a tool called incredibuild at work. Does GCC (or another project?) allow distributed compiling like incredibuild?
:)
It really cuts down your build times when you've got the power of a virtual 50Ghz machine
thus, I can follow the development list.
3.2 broke binary compatability with 3.1, right? and 3.1 (modified) is what is used in OS X 10.2. Does this mean Apple will have to do a lot of munging to use 3.3?
As far as I can tell, there is nothing as good as Visual Studio for Linux. Naturally, this was a huge disappointment to me when we migrated from NT to Linux at work.
Don't get me wrong - KDevelop is a brave attempt, and coming along, but it just doesn't match Visual Studio. The most incredibly irritating thing about it is the diabolical project management. I had to hack my copy just to make it slightly useful at all, and eventually I just gave up on it. Now I use jedit, handmade makefiles and kdbg. I still miss MSDEV, though.
Fairly soon I'll try KDevelop 3 again to see how it's come along, but if you're used to Visual Studio, you will be disappointed.
I'm still trying to find a nice GUI-driven debugger, as kdbg seems rather flaky.
so it shouldn't be affected by this particular regression.
As far as I can tell, Anjuta suffers from the same problem as KDevelop - very inflexible automake-based project management. Otherwise I'd be up for using it, but the project management stuff is such a pain in the ass.
It is pretty easy to do with a parallel make (GNU make is fine) and a wrapper script that rsh gcc to apropriate machines. I did it back in school when I had access to lots of Unix machines.
I don't know if there is any projects to formalize this, but in these SourceForge days there most likely is.
I clicked on one of the intel ads last night and was debating wether or not to download the 'unsupported' linux version of intel C & Fortran. Mostly just to play around with.
I'm wondering if anyone here has played with intel (esp under Debian) C and has any comments on it versus GCC.
Also [on a fortran note] if it would be worth getting intel fortran for the sake of fortran 95 support, or should I stick w/ the ubiquitous [sp?] gcc/fortran 77 which runs everywhere?
Opinions, anyone?
look here
About every GCC release breaks most of the software written for previous version, especially for C++, as it's standard keeps "refining" constantly, as does GCC's interpretation of it. Not to mention the extensions.
Right now I'm busy changing all "#include" to "#include", "friend Foo" to "friend class Foo", and adding "using namespace std" everywhere. What next?
I have always been amazed that such an impressive compiler is still free. Thanks to the GCC team. You guys/gals rock!
Anonymous Cowards suck.
I SAID ENN-GODDAMNED-TEE
And why release it?
It fixes lots of bugs, obviously people who have been bitten by these bugs will want them fixed as soon as possible. And those who need the new feautures tend to need them yesterday.
All these people are developers. I do not see any reason for non-developers to care, just use the compiler bundled with your OS.
BTW the last full release was 3.1, quite some time ago. All the intermediate releases (including 3.2) have been bug fix releases with no new features.
It's a shame that no one managed to fix bug #10392 before release. Until that one's fixed, those of us who do Dreamcast hacking are stuck using GCC 3.0.4.
install both and measure. My application, a numerical simulation written in C++, was 5% slower when compiled with icc. The better benchmarks show the same thing, icc is faster for some tasks and slower for others, but expect for very specialized tasks they tend to be in the same ballpark for real applications.
The patch in the original bug post looks like this:
/* Can't remember if & or -> is evaluated first, so I added () */
- ConfigItem** ip = &(ConfigItem*)menu->data;
+ ConfigItem* i=(ConfigItem*)menu->data;
+ ConfigItem** ip =
So I guess you're right; the & operator would use an lvalue. One could code *(void*)5, but not &(void*)5.
The way I would've coded that particular code in one line is:
ConfigItem** ip = (ConfigItem**)&(menu->data);
Or the (unsigned int *) example case you gave as:
voidpointer = (void *)uintpointer;
So, I really don't see this extension as anything more than a potential way for increasing gratuitous obfuscation for the purpose of the obfuscated C contest.
A solution to the problem with music today
Or more accurately *5 vs. &5.
macosx% gcc --version
gcc (GCC) 3.1 20020420 (prerelease)
Not going to go grab the latest GCC because I wouldn't count on it to work with ObjC, MachO, and whatever else Apple may still be patching in.
Start Running Better Polls
"...to some extent." Why give a Subject: line textbox that won't let me use all of it? Grrr.
Anyhow. One of the big speed hits for iostream code was the formatting routines. Some other reply has a subject like "if you're using fstream you're not interested in performance anyhow," which is so wrongheaded I won't even bother to read it. There's no reason why iostreams code shouldn't be faster than the equivalent stdio code: the choice of formatting operations is done at compile-time for iostreams, but stdio has to parse the little "%-whatever" formatting specs at runtime.
However, many iostreams libraries are implemented as small layers on top of stdio for portability and compatability, which means that particular implementation will always be slower.
We were doing something similar until recently. Not a complete layer on top of stdio, but some of the formatting routines were being used for correctness' sake. We all knew it sucked, but none of the 6 maintainers had time to do anything about it, and the rest of the world (that includes y'all, /.) was content to bitch about it rather than submit patches. Finally, Jerry Quinn started a series of rewrites and replacements of that section of code, aimed at bringing performance back to 2.x levels. One of the newer maintainers, Paolo Carlini, has been working unceasingly at iostream and string performance since.
So, all of that will be in 3.4. Chunks of it are also in 3.3, but not all. (I don't recall exactly how much.)
You cannot apply a technological solution to a sociological problem. (Edwards' Law)
>>The preprocessor now accepts directives within macro arguments. It processes them just as if they had not been within macro arguments.
The separate ISO and traditional preprocessors have been completely removed. The front-end handles either type of preprocessed output if necessary.
This quote below makes me hopeful.
I've had trouble with this macro in gcc:
#define TRIGGER_PUSHBUTTON(c)
((PUSHBUTTON16) | 'c')
gcc doesn't like having the macro add the quotes around the character argument. Only works if you to leave the quotes out of the macro definition and require them in the macro argument.
But I have a lot of code written on AIX that uses this macro (and others like it). Porting to linux requires 'fixing' all the occurrances.
Anybody know if this applies?
Posted from my Android phone. Oh, I can change this? There, that's better...
d00d! YU0=t3h $u}{0R, I=31337 ]-[@}{0R. 101101101101!!! -g0thm011y
I've noticed in gcc 3.x that #include "header.h" looks for system header matches *before local scoped headers.
Is it just me or is that wrong and annoying?
I've had to distribute shell scripts to swap out filenames for compilation ( which wouldn't be fun to do by hand, trust me ) everytime gcc3 compiles the code base.
I don't track gcc3.x, but has this been fixed or is it intentional to cause confilcts you can't possibly predict on another system?
Here's a problem you could predict as an example:
#include "endian.h"
Then lots of odd compile errors ensue confusing the user. Also #include seemly includes -- wtf is up with that? Are these people using old/bad gcc3.x builds?
http://www.gnuenterprise.org/project/what.html
Why give a Subject: line textbox that won't let me use all of it?
Because your browser is using a proportional font. Would you want the box to resize, triggering a reflow, every time you type a character? Even with the user-code performance improvements of the GCC 3.x series, the median user would still get lag.
Will I retire or break 10K?
No where does it say that a "real" i686 must have cmov, the compiler should check for cmov before using it.
The cmov instruction is used in tight loops. Would you really want to branch around cmov at run time based on the cpuid? It'd completely defeat the purpose of cmov. I say define "i686" as an ia-32 CPU with cmov and leave it at that.
Will I retire or break 10K?
Anyone known if this release fixes the march=pentium4 bug that exists in 3.2.x?
Check your own boxen with:
# python -c 'int(10000.3);'
I'm the one who filled the bug report, so I should
have known better.
I don't see why anyone would accept the current libc++ for anything else but a beta or even an alpha release.
It probably doesn't get noticed so much because fstream isn't used that much.
For something like koffice or kmail, assuming it uses fstream, I suspect that one would notice the difference.
Just kidding. Eat my shorts.
The Intel compiler on Windows is about 30% faster than VC++ (version 6, we have not tried the .net version yet) with these same C++ programs, and the result is perhaps 4% faster than the GCC 2.9.6 Linux version (the program is entirely compute-bound, so this is not an OS difference). So far we have not seen even this 4% improvement in the Linux Intel compiler, which leads me to believe they have not put as much work into it as they did for the Windows one.
http://www.openmp.org/
With Dual CPU systems and Hyperthreading, you can get near 2X advantages on quite a few algorithms.
I haven't kept up with Gnu's OpenMP stuff. I guess this is one such project. http://savannah.nongnu.org/projects/gomp/
With gcc these days is it safe to compile my linux kernel and other stuff optimized for a particular cpu (eg: Athlon K7)? I read somewhere not to do this for the kernel? Grunt, we wants! :-)
... is find something Better Than Ezra.
Okay, it's a groaner.
I do development work using gcc on my local Mandrake machine with 3.2. I tried to compile one of my projects on our server which uses gcc 2.96 and it fails (3.2 follows the ANSI C++ standard, 2.96 is old-style) due to the older C++ libs. I want to upgrade our server to gcc 3.2, but since we've got other projects that work fine under 2.96, we are afraid of breaking the other projects (especially since we are close to release). Does anyone know of any gotchas? Can I just download, compile, and install 3.3 (or 3.2)? Will I also need to download, compile and install a new glibc? Can I install gcc 3.3 and not change my glibc version? Thanks, - Steve
I've seen numbers anywhere from 5%-200% penalty, though I don't have any references at the moment. It really depends on the app and where your main execution time lies. If you do a lot of tight loops over arrays, it's going to give you a significant performance hit. If you don't, it won't. So it's probably going to slow down your MP3 encoder a lot, but probably won't result in a noticeable slowdown for most userland apps. For most apps, which are I/O- rather than CPU-bound anyway, it's a good idea for security reasons. Same reason strncpy() is recommended over strcpy(), despite the performance hit due to bounds checking (in fact, strncpy() is just a special-case example of bounds checking).
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
I heard a rumour somewhere that if ICC detects an AMD CPU, it either compiles the code to slower code (if it's compiling on an AMD CPU), or it builds EXE's that detect if it's running on an Intel or AMD and if running on an AMD, the EXE runs a bit slower. This was not true for early versions of ICC but at a certain version, they added this detection. Anyone know anything more about this?
The compile server was still experimental last I heard.
You need to reorganize your Make files to use pch's efficiently. You should
1) Not change any of your source or header files.
2) Add a new "all.h" header including all other headers, and precompile that header and only that header, whenever any other header changes.
3) all.h should not be included directly from any file, instead compile with a special flag that "pre-includes" all.h.
4) Because of header guards (which you must use), none of the normal header files will be included.
5) Because no file include all.h directly, it will not figure in the autmatic generated dependencies, and you should not add it manually. Thus, any source file will be recompiled only when the header files it includes directly are changed.
This solves the "only one include file" problem AC mentions, and means the source and include files are identical to the non-PCH version.
The danger is that there might creep in hidden dependencies, i.e. source files that does not include all the headers they should, yet compile due to the pre-include of all.h. So you will have to make an occational build without PCH.