Re: Inlining and estimate_num_insns
Steven Bosscher <[EMAIL PROTECTED]> wrote: >> In the end we surely want to watch CiSBE and SPEC testers. > > Maybe so, but your timings already show this is pretty unacceptable. I strongly object this. Benchmarks show that we are doing *much* worse at inlining in 4.0, and we are seeing bad regressions in code generation because of that. Richard's patches are simply restoring the 3.4 behaviour and fixing this *bad* regression. If compile time goes high, then sorry, it's because of other things. Maybe tree-ssa, who knows. If we got good compile times because an optimization was accidentally disabled, keeping it disabled is not the good thing to do. -O3 means we want to try to inline everything, and that will cost something. Keeping the mainline broken in this regard because we save some compilation time at -O3 is nonsense. Otherwise, please give me -O4 and I'll let you use this broken -O3 which does nothing. And I am only half joking here. If saving some compilation time at -O3 and losing so much in code generation is that important to you, then please allow me to have a flag -finline-functions-non-broken, and -O4. Personally, I find Richard's patches so correct in fixing this big regression which I am surprised they find so much opposition. I kindly ask you to reconsider your position. Giovanni Bajo
Re: Inlining and estimate_num_insns
Mark Mitchell <[EMAIL PROTECTED]> wrote: > 1. The C++ community has split into two sub-communities. One is very > heavily focused on template metaprogramming. The other is doing more > "traditional" object-oriented programming. I would postulate that most of the times the former group are those writing *libraries*, and the latter group is those using the libraries to produce applications. > The kinds of programs > written by these two communities are drastically different, even > though, obviously, there is overlap between the two, mixed programs, > etc. But, programmers in one camp tend to think that their style is > "very common" while that of the other camp is "fancy" or > "complicated". The truth is that both are now mainstream uses of > C++, and we need to try to work well with both kinds of code. Let's remember also that template metaprogramming is used in v3 itself (and much more so when TR1 is fully merged), in Boost, in UBLAS, and many other libraries. There are thousands of applications which are written in the traditional object-oriented paradigm, and still make heavy use the above libraries. > 2. I don't think we should be make any changes at this point without a > relatively comprehensive benchmarking effort. That means more than a > few programs, compiled on multiple architectures, with measurements of > both compile-time and runtime performance. I'd suggest that tramp3d > is fine, but I'd also suggesting looking at KDE, Boost, and > libstdc++-v3. I'd try to measure total compilation time, total code > size, and some measure of performance. (Since C++ inlining should > generally -- but not always, of course -- result in smaller code due > to removal of calls, code size is probably a rough proxy of > performance.) Richard showed already how his patches help on some of the benchamarks you suggested. They also fix a regression since 3.4 was so much better in this regard. Of course, compilation time goes up somehow because we are doing more work now, but the compile time *regression* is probably because of something else and is merely uncovered by Richard's patches. We also got reports from other people saying that Richard's patches help. I'm not sure we should hold such a patch to save a few percent of compilation time at -O3. -O3 (compared to -O2) means "try to inline harder". Richard's patches are doing exactly that. I'm sure who uses -O3 doesn't mind us doing better what we are asked for. And if compilation time is critical for them, they can still use -O2. Also, I would like to see detailed reports of where the compilation time goes, after the patch. I'm sure we can go blaming other optimizers (probably some of the new ones) for the compile time regression. Giovanni Bajo
Re: Extension compatibility policy
Marc Espie <[EMAIL PROTECTED]> wrote: > Personally, I would even say that it would be *great* if gcc would > start warning if you use any extension, unless you explicitly disable > those warnings... (except for __extension__ in header files, and then > I've stumbled upon situations where it hurts still). That is *exactly* what -pedantic is meant to be. If it does not, patches are welcome. Giovanni Bajo
Re: Extension compatibility policy
Mike Hearn <[EMAIL PROTECTED]> wrote: > As recent releases have broken more and more code, I would like to > understand what GCCs policy on source compatibility is. Sometimes the > code was buggy, in this particular case GCC simply decided to pull an > extension it has offered for years. Is it documented anywhere? Are > there any more planned breakages? How do you make the cost:benefit > judgement call? Are there any guidelines you follow? First, you must understand the difference between a real extension and something that always worked with GCC but was never supposed to. In the former group, you place things which are well-documented in the GCC manual, they are disabled if you add the -pedantic option, are probably widely known (like many of those GCC extensions that make it into C99 in some form, say designated initializer), etc. In the latter group, there are all those mostly obscure cases where there is a piece of code which is illegal by ISO standards but GCC used to accept somehow. The former group is handled with care, more often than not. Deprecations usually involve a full release cycle (which is around 12 months), and they are notified in the release notes (for instance, see http://gcc.gnu.org/gcc-3.4/changes.html for the release notes of GCC 3.4). Sometimes, deprecation time can be increased if users complain enough. The latter group is basically made of bugs of the GCC compiler. "Accepting a piece of code which is invalid" is the specular version of "rejecting a piece of code which is valid", and I am sure everybody agrees that this is a bug. In fact, in Bugzilla we have two keywords to mark these bugs: "accepts-invalid" and "rejects-valid". We cannot really have a deprecation cycle to fix bugs: GCC would be moving even slower than it does (or used to). Notice that this situation is mostly common with C++ code, where we used to have wa to many "accepts-invalid" bugs. Every once in a while people jump in complaining about no deprecation cycle for having fixed this or that bug which greatly affect their codebases, but there is really nothing we can do about that. In your __FUNCTION__ case, we are basically in the latter group. __FUNCTION__ is a well-documented extension in C90 (it's part of C99 in some form now), and it was never documented to be a macro. The fact that was named like a macro and worked like a macro for years is indeed unfortunate. Notwithstanding that, GCC maintainers acknowledged its widespread use and the bug of it working like a macro was deprecated for around 3 years. We cannot do more than that. GCC 2.95 is really old, people *should* expect trouble while upgrading to 3.4, or 4.0. I would be *really* surprised to hear a notransition from 2.95 to 4.0 which does not require any modification (for non-trivial codebases of course). Giovanni Bajo
Re: http://gcc.gnu.org/gcc-3.4/changes.html
Johan Bergman (KI/EAB) <[EMAIL PROTECTED]> wrote: > I propose the following change to > http://gcc.gnu.org/gcc-3.4/changes.html. (The "alternative solution" > was proposed by myself a while ago, > but now I have realized that it is not backwards compatible.) Please post the patch as an unified diff, and attach it to the mail rather than copying within it. Giovanni Bajo
Re: invoke.texi: reference to web page that does not exist
Devang Patel <[EMAIL PROTECTED]> wrote: > invoke.texi mentions following URL for further info on visibility > #pragmas. >http://www.nedprod.com/programs/gccvisibility.html > but it does not exist. The page was up and working no longer than 2 weeks ago. Niall Douglas (which I'm CC:ing) is the owner of that page. Niall, are you planning to get the site back up and running soon? If not, can we get a copy of gccvisibility.html so that we can extract the text and host it locally? Thanks Giovanni Bajo
Re: [PING] [PATCH]: New Port(MAXQ)
Konark Goel, Noida <[EMAIL PROTECTED]> wrote: > We submitted a patch for a new port for MAXQ architecture. > The original patch is > (http://gcc.gnu.org/ml/gcc-patches/2004-12/msg02138.html) > The revised patch after incorporating few comments is > (http://gcc.gnu.org/ml/gcc-patches/2005-01/msg00521.html) > Please let us know if that patch is acceptable. Can you also post the result of a testsuite run to the testresult mailing list to make sure the port is somewhat stable? Was the copyright assignment to FSF filed for either the whole company or the authors of the port? Mark, how does this port fit in the 4.1 plan? Since it is totally self-contained (it does not modify anything in GCC proper but the usual configuration additions), I think it could be merged any time, assuming a global maintainer can spend some time on a review. To be fair, this patch was posted last December with mainline in Stage 3 (and got almost no comments), so if the patch is approved, it could be added to 4.0 too (given absolutely zero risk). Giovanni Bajo
Using fold() in frontends
Mark Mitchell <[EMAIL PROTECTED]> wrote: >> If the parser can't be used to provide useful context, we could >> potentially postpone the calling of "fold" for C++ COND_EXPRs during >> parsing, but call "fold" on COND_EXPRs while lowering to gimple, where >> we'll always know whether we're expecting lvalues/rvalues. > > We should do that for *all* calls to fold. A patch to do that would be > most welcome! It looks like the general consensus is that we should not use fold() anymore in the frontends (I consider gimplify part of middle-end already, as it is mostly language-independent). I know Java people also are trying to remove usage of fold() since it produces simplifications which are not allowed in the Java semantics of constant expressions. But how are you proposing to handle the fact that the C++ FE needs to fold constant expressions (in the ISO C++ sense of 'constant expressions)? For instance, we need to fold "1+1" into "2" much before gimplification. Should a part of fold() be extracted and duplicated in the C++ frontend? -- Giovanni Bajo
Re: [Bug c++/19199] [3.3/3.4/4.0/4.1 Regression] Wrong warning about returning a reference to a temporary
Steven Bosscher <[EMAIL PROTECTED]> wrote: >> The way I think about this is that G++ has long supported the GNU >> min/max expression extension -- and it's long been broken. Over the >> years, I've fielded several bug reports about that extension, and we've >> gradually cleaned it up, but mostly it's just been neglected. > > Indeed, not so very long a go I helped pinning down a bug in the RTL > expanders for MIN_EXPR and MAX_EXPR (I think that Roger fixed it) that > made it impossible for that extension to work relyably. The reason we > found it is that the tree optimizers produces a few (and hopefully it > will produce more of them soon), but the bug in the expanders had been > there since the dawn of time. And nobody noticed it before. Well, that sounds largely impossible. Can you point exactly which bug are you talking of? I know for a fact that the extension itself has always worked for basic rvalue usage, with basic types. Instead, I would not be surprised if some more complex usage of it used to be (or still is) broken, like weird lvalue contexts, usage in templates, operator overloading or similar. -- Giovanni Bajo
Deprecating min/max extension in C++
Andrew Pinski <[EMAIL PROTECTED]> wrote: >> Well, that sounds largely impossible. Can you point exactly which bug >> are >> you talking of? I know for a fact that the extension itself has always >> worked for basic rvalue usage, with basic types. Instead, I would not >> be >> surprised if some more complex usage of it used to be (or still is) >> broken, >> like weird lvalue contexts, usage in templates, operator overloading or >> similar. > > Yes this was PR 19068 and bug 18548. Thanks. Nonetheless, both are regressions, and both shows a rather complex situation which includes pointer tricks. My statement that basic usage of the extension has always worked still holds. -- Giovanni Bajo
Deprecating min/max extension in C++
Mark Mitchell <[EMAIL PROTECTED]> wrote:
> IMO, if these are C++-only, it's relatively easy to deprecate these
> extension -- but I'd like to hear from Jason and Nathan, and also the
> user community before we do that. Of all the extensions we've had, this
> one really hasn't been that problematic.
I would prefer them to stay. My reasons:
1) std::min() and std::max() are not exact replacements. For instance, you
cannot do std::min(3, 4.0f) because the arguments are of different type.
Also, you cannot use reference to non-const types as arguments. The min/max
exensions do not suffer from these problems (I consider the former very
problematic, and the latter just annoying).
2) The min/max assignments are very useful. I'm speaking of the
(undocumented?) ">?=" and "?= Compute(i) * factor;
instead of:
for (int i=0;i<100;i++)
{
float cur = Compute(i) * factor;
if (max_computed < cur)
max_computed = cur;
}
I find the former more compact, more expressive and much easier to read (of
course, you have to know to syntax). I find it also less error-prone since
there is no duplication, nor the use of a variable to prevent side-effects.
I suppose that if we drop ">?" and "?=" and
"
Re: Deprecating min/max extension in C++
Gabriel Dos Reis <[EMAIL PROTECTED]> wrote: >>> IMO, if these are C++-only, it's relatively easy to deprecate these >>> extension -- but I'd like to hear from Jason and Nathan, and also the >>> user community before we do that. Of all the extensions we've had, this >>> one really hasn't been that problematic. >> >> I would prefer them to stay. My reasons: >> >> 1) std::min() and std::max() are not exact replacements. For instance, you >> cannot do std::min(3, 4.0f) because the arguments are of different type. > > That is a rather weak argument. What is the type of the argument if > it were possible? "float" of course, like we do for 3 + 4.0f. > If float, why can't you write 3f? If int, why can't > you write 4? Because the example was just an example. In real code, "3" is probably a variable of integer type, and "4.0f" is probably a variable of floating point type. Going on this way, why don't we to propose to deprecate "+" in C++ because std::plus can be used as a replacement? I'm sure people won't be happy to be unable to add an integer and a long. > With the ominpresence of function templates and the > rather picky template-argument deduction process, how useful is that > fuzzy-typed constructs with rather dubious semantics and implementation? It is useful for me. It has been many times. It avoided me to write casts which are otherwise necessary. I don't think I will have to explain you the domain of the problem, why that single variable was float or int, and so on. My statement is that std::min() is *not* an exact replacement for I would like to see those extensions deprecated and go with no return. I would like to propose them for standardization. It is just too bad I don't have time to prepare the papers. -- Giovanni Bajo
Re: Deprecating min/max extension in C++
Gabriel Dos Reis <[EMAIL PROTECTED]> wrote: >> Because the example was just an example. In real code, "3" is probably a >> variable of integer type, and "4.0f" is probably a variable of floating >> point type. > > Which we have not seen yet, for the purpose of assessing the purpoted > usefulness in real codes. Arguments are easily made with xyz examples. Are you disputing the usefulness of promotion rules with operators? If you agree that promotion is useful, I cannot see why it should not be for min/max operators. -- Giovanni Bajo
Re: Deprecating min/max extension in C++
Gabriel Dos Reis <[EMAIL PROTECTED]> wrote: >>>> Because the example was just an example. In real code, "3" is probably a >>>> variable of integer type, and "4.0f" is probably a variable of floating >>>> point type. >>> >>> Which we have not seen yet, for the purpose of assessing the purpoted >>> usefulness in real codes. Arguments are easily made with xyz examples. >> >> >> Are you disputing the usefulness of promotion rules with operators? If you > > I'm disputing the extensions ? when we have a standard > min()and max(). ... which do not handle promotions. So you do not consider useful to have a min/max operator with promotion (so that it would work exactly like any other operator) just because there is a cheap version without promotion. And my statement that min() and max() are not exact replacements still stands. We'll disagree, as happens. Since there is no exact replacements (especially for the min/max assignment operators), and the extensions are definitely not so troublesome, I would like them to stay. -- Giovanni Bajo
Re: Bad link on webpage
Marcus <[EMAIL PROTECTED]> wrote: > On the page, http://gcc.gnu.org/gcc-4.0/changes.html, the link > http://www.nedprod.com/programs/gccvisibility.html (near the end of the > document) contains > > ``DOMAIN HOLDING PAGE > > This is a holding page for a domain registered by Total Registrations on > behalf of a customer. At this present time the owner of the domain name has > simply registered the name and has not chosen to host a web site or receive > email through it. '' I'm taking care of this. If the site does not appear again soon, I'll remove the link. I would like to still get hold of the information that used to be present at that page because they were in fact very useful. -- Giovanni Bajo
Re: Bad link on webpage
James E Wilson <[EMAIL PROTECTED]> wrote: >> I would like to still get hold of the information that used to be present at >> that page because they were in fact very useful. > > This is what web search engines are for. Going to yahoo, typing gcc > visibility, and then clicking on the "cached" link for the first search > result, I get a copy of the page. > http://216.109.117.135/search/cache?p=gcc+visibility&sm=Yahoo%21+Search&toggle=1&ei=UTF-8&u=www.nedprod.com/programs/gccvisibility.html&w=gcc+visibility&d=C31F2BCCE8&icp=1&.intl=us Ah thank you! It's obvious, but for some reason I tried webarchive.com but google didn't occur to me! :) I'll put this into the Wiki, and update the webpage. (notice: I use the Wiki because otherwise I'll have to wait weeks for the approval, and I don't have the time nor the willing of pushing a patch for weeks just for this. I believe we should either be more liberal with the contents of our website, or get more reviewers. For instance, we could think of a policy where a www patch can be applied after 48hrs if nobody says otherwise). -- Giovanni Bajo
Re: Bad link on webpage
James E Wilson <[EMAIL PROTECTED]> wrote: >> I would like to still get hold of the information that used to be present at >> that page because they were in fact very useful. > > This is what web search engines are for. Going to yahoo, typing gcc > visibility, and then clicking on the "cached" link for the first search > result, I get a copy of the page. > http://216.109.117.135/search/cache?p=gcc+visibility&sm=Yahoo%21+Search&toggle=1&ei=UTF-8&u=www.nedprod.com/programs/gccvisibility.html&w=gcc+visibility&d=C31F2BCCE8&icp=1&.intl=us OK, done. Link: http://gcc.gnu.org/wiki/Visibility. Can someone patch changes.html and restore the link in the documentation that was deleted a few days ago? -- Giovanni Bajo
Revamp WWW review process?
Joseph S. Myers <[EMAIL PROTECTED]> wrote: >> (notice: I use the Wiki because otherwise I'll have to wait weeks for the >> approval, and I don't have the time nor the willing of pushing a patch for >> weeks just for this. I believe we should either be more liberal with the >> contents of our website, or get more reviewers. For instance, we could think >> of a policy where a www patch can be applied after 48hrs if nobody says >> otherwise). > > You may not have noticed that Gerald is away until 13 March. Otherwise > website patches do get reviewed quickly. I think they are not reviewed quickly enough anyway. I do not have evidence (statistics) to bring forward, so feel free to ignore my opinion. I know for sure that some of my www patches had to be pinged, or went unreviewed for weeks. I'm not trying to accuse Gerald, I just believe that we should just find a faster path to get www patches in. I find it funny that Dorit has to ping two times a patch that describes changes to the vectorizer, for instance. A problem is that a technical www patch is often deferred to a maintainer of the specific area of the compiler. For instance, if I want to write something on the site which speaks about C++, I need a buy-in from both Gerald and a C++ maintainer. This much often than not requires pings and long waits. Getting a patch which basically explains a known change in Bugzilla into changes.html can easily take a week, between Gerald's and Mark/Jason/Nathan. With such an overhead, I'm unimpressed that changes.html is always incomplete, and develepors often update it only after explicit prompts from the Bugmasters. My personal feeling I think the success of the Wiki is that it does not require review, rather than the fact that the Wiki syntax is partially lighter than HTML. The 48-hrs rule I propose seems sensible to me. The worst thing that can happen is that something incorrect goes live on the site, and it'll eventually get fixed when someone reads the patch a few days later. -- Giovanni Bajo
Re: documentation on writing testcases?
Per Bothner <[EMAIL PROTECTED]> wrote: > The general frustration is: where is dg-error documented? > I looked in: > - the README* files in gcc/testsuite and in gcc.dg; > - the Test Suites chapter of the internals manual > (which mentions "special idioms" but not the basics); > - the "Testsuite Conventions" of codingconventions.html; > - contribute.html; > - install/test.html; > - and of course Google. > > In *none* of these did I find documentation on how to write or > understand a test-case, or a link to such documentation. I'm inclined > to think that most of these above places should have such a link. I had provided this patch in the past, but was rejected: http://gcc.gnu.org/ml/gcc-patches/2004-06/msg00313.html I never had time to split, rewrite in tex, and update it as requested. Janis recently incorporated some parts into the internal manuals, but I believe that we still nedd provide a "tutorial for GCC testcase writing". Like I'm trying to explain in another thread, I believe that we are being way too picky on www/documentation patches than we should be. For instance, my patch could have been committed immediatly and been refined over time. In fact, I should find a couple of hours to add it to the Wiki. -- Giovanni Bajo
Re: Documentation on writing testcases now in GCC Wiki
Michael Cieslinski <[EMAIL PROTECTED]> wrote: > I formatted the infomation from Giovanni Bajo's patch and put it in the > Wiki: http://gcc.gnu.org/wiki/HowToPrepareATestcase Many thanks! -- Giovanni Bajo
Re: Questions about trampolines
Robert Dewar <[EMAIL PROTECTED]> wrote: >>> Well as I said above, trampolines or an equivalent are currently critically >>> needed by some front ends (and of course by anyone using the (very useful >>> IMO) extension of nested functions in C). >> >> This is your opinion, but I've yet to find an actual piece of code in a >> real project that uses that extension. > > I have certainly seen it used, but you may well be right that it is > seldom used. It is certainly reasonable to consider removing this > extension from C and C++. Anyone using that feature? Or know anyone > who is. Last time this was discussed on gcc@, there was an agreement that since we have to support trampolines for Ada & co., we can as well keep the extension in C, which allows easier testcases, reductions (as most developers do not understand Ada) and let the feature be tested even within gcc.dg. -- Giovanni Bajo
Re: Merging calls to `abort'
Richard Kenner <[EMAIL PROTECTED]> wrote: > However, the idea that users could search for previous bug > reports is new to me. That might be an additional reason for > using fancy_abort. > > It's not just users, but first level tech-support. There, it can help > in suggesting a workaround to the user and knowing which file the > abort is in may help assign the bug to the appropriate developer. Absolutely true. As a GCC bugmaster, I can confirm that receiving bug reports with clear indication of the file name and the function name is incredibly useful. Not only it lets us find duplicates in seconds, or assign recent regressions to the responsible in a shot, but it also provides an immediate indication of which kind of bug it is. Otherwise, we would be forced to run GDB on the testcases just to categorize a bug. The abuse of abort() in GNU software is unfortunate. I agree with Mark when he says that a naked abort should be used only after useful information has already been printed to the user. In fact, we are in the middle of a conversion of the whole GCC codebase from abort() to assert() (even if our abort() is a fancy_abort() in disguise!). Giovanni Bajo
Re: Why aren't assignment operators inherited automatically?
Topi Maenpaa <[EMAIL PROTECTED]> wrote: > In short, anything inherited from the base class can be used as > expected, except the assignment operator. What's the deal? I'm doing > this on Mandrake > 10.1, gcc 3.4.1, if that matters. This is what the standard says. Giovanni Bajo
Re: Newlib _ctype_ alias kludge now invalid due to PR middle-end/15700 fix.
Hans-Peter Nilsson <[EMAIL PROTECTED]> wrote: > So, the previously-questionable newlib alias-to-offset-in-table > kludge is finally judged invalid. This is a heads-up for newlib > users. IMHO it's not a GCC bug, though there's surely going to > be some commotion. Maybe a NEWS item is called for, I dunno. It will be in NEWS, since RTH already updated http://gcc.gnu.org/gcc-4.0/changes.html. I hope newlib will be promptly fixed. Giovanni Bajo
Re: Compiler chokes on a simple template - why?
Topi Maenpaa <[EMAIL PROTECTED]> wrote:
> ---
> template class A
> {
> public:
> template void test(T value) {}
> };
>
> template void test2(A& a, T val)
> {
> a.test(val);
> }
>
> int main()
> {
> A a;
> a.test(1); //works fine
> }
> ---
This is ill-formed. You need to write:
a.template test(val);
because 'a' is a dependent name.
> The funny thing is that if I change the name of the "test2" function
> to "test", everything is OK. The compiler complains only if the
> functions have different names. Why does the name matter?
This is surely a bug. Would you please file a bug report about this?
> The code compiles if "test2" is not a template function. Furthermore,
> calling A::test directly from main rather than through the
> template function works fine.
This is correct, because if "test2" is not a template function name anymore,
then 'a' is not a dependent name, and the 'template' keyword is not needed to
disambiguate the parser.
Giovanni Bajo
Re: Known regression ? gcc-4.0.0-20050312 FPE's on C++
John Vickers <[EMAIL PROTECTED]> wrote: > I can have another go without the "--disable-checking" if that's > likely to help. Anything else you'd like in the bug report ? Please submit the smallest preprocessed source you can machine-generate which shows the bug. Thanks! Giovanni Bajo
Re: reload-branch created (was: What to do with new-ra for GCC 4.0)
Bernd Schmidt <[EMAIL PROTECTED]> wrote: >>> It might also be easier for those of us who want to play with the >>> code, without having to find a suitable sync point between the >>> patch and >>> mainline sources. >> >> I have created a new branch, "reload-branch", on which I'm going to >> check in these changes. Once I've done that, I'll commit the patch >> below to mention the branch in the documentation. Thanks! You should also mention in cvs.html that you are the maintainer of the branch (together with Ulrich, maybe?). What is your plan for this branch? Is there more code refactoring/rewriting planned, or are you just going to give it a wider testing and fix fallout bugs, in preparation for a merge? Giovanni Bajo
Re: AVR indirect_jump addresses limited to 16 bits
Paul Schlie <[EMAIL PROTECTED]> wrote:
> - Sorry, I'm confused; can you give me an example of legal C
> expression specifying an indirect jump to an arbitrary location
> within a function?
It is possible in GNU C at least:
int foo(int dest)
{
__label__ l1, l2, l3;
void *lb[] = { &&l1, &&l2, &&l3 };
int x = 0;
goto *lb[dest];
l1:
x += 1;
l2:
x += 1;
l3:
x += 1;
return x;
}
I would not design a backend so that such a feature is deemed to be impossible
to support.
Giovanni Bajo
Re: maybe a gcc bug
zouq <[EMAIL PROTECTED]> wrote:
> /testcom.c
> int main (void)
> {
> int i,j;
> int u[100][100], v[100][100],
> p[100][100], unew[100][100],
> vnew[100][100],pnew[100][100],
> uold[100][100],vold[100][100],
> pold[100][100],cu[100][100],
> cv[100][100],z[100][100],h[100][100],psi[100][100];
>
> int tdts8=2;
> int tdtsdx=3;
> int tdtsdy=4;
>
> for (i=0;i<100;i++)
>for (j=0;j<100;j++)
>{
>unew[i+1][j]=uold[i+1][j]+tdts8*(z[i+1][j]+z[i+1][j])*
> (cv[i+1][j+1]+cv[i][j+1]+cv[i][j]+cv[i+1][j])
> -tdtsdx*(h[i+1][j]-h[i][j]);
>/*vnew[i][j+1]=vold[i][j+1]-tdts8*(z[i+1][j+1]+z[i][j+1])
> *(cu[i+1][j+1]+cu[i][j+1]+cu[i][j]+cu[i+1][j])
> -tdtsdy*(h[i][j+1]-h[i][j]);*/
>/*pnew[i][j]=pold[i][j]-tdtsdx*(cu[i+1][j]-cu[i][j])-
> tdtsdy*(cv[i][j+1]-cv[i][j]);*/
>
>}
>
> for (i=0;i<100;i++)
>for (j=0;j<100;j++)
> printf ("%d\n%d\n%d\n",unew[i][j], vnew[i][j], pnew[i][j]);
>
> return 1;
> }
>
> first i made gcc-4.1-20050320 a cross-compiler for powerpc.
> when i compile the above program, it goes like this:
>
> testcom.c:34: internal compiler error: in schedule_insns, at
sched-rgn.c:2549
>
> who can tell me why?
> why can it bring compiler error?
Any compiler error, *whichever* source file you use, is a bug of GCC. Would
you please submit this as a proper bugreport in Bugzilla? Read the
instructions at http://gcc.gnu.org/bugs.html.
Thanks
--
Giovanni Bajo
Re: GCC 4.1 bootstrap failed at ia64-*-linux
James E Wilson <[EMAIL PROTECTED]> wrote: >> IA64 bootstrap failed at abi_check stage reporting undefined >> references from libstdc++ (see log at the bottom). > > This seems indirectly related to bug 20964. Mark's proposed fix to > stop building abi-check at bootstrap time means the IA-64 bootstrap > should now succeed. This testcase will still be broken, but now it > will only be a make check failure instead of a make bootstrap failure. Typo, you meant PR 20694. Giovanni Bajo
Re: 4.0 regression: g++ class layout on PPC32 has changed
Andrew Haley <[EMAIL PROTECTED]> wrote: > public: > long long __attribute__((aligned(__alignof__( ::java::lang::Object l; I don't recall the exact details, but I have fixed a couple of bugs about the use of __alignof__ and attribute aligned on members of classes (maybe templates only?). Are you positive this attribute declaration *does* have an effect at all in 3.4? -- Giovanni Bajo
Re: 4.0 regression: g++ class layout on PPC32 has changed
Andrew Haley <[EMAIL PROTECTED]> wrote: > > > public: > > > long long __attribute__((aligned(__alignof__( ::java::lang::Object > > l; > > > > I don't recall the exact details, but I have fixed a couple of bugs about > > the use of __alignof__ and attribute aligned on members of classes (maybe > > templates only?). Are you positive this attribute declaration *does* have > an > effect at all in 3.4? > > It seems to be the other way around. > > The attribute declaration does have an effect in 3.4 -- the offset > changes from 52 to 56 -- but it does not have any effect in 4.0, and > this is what breaks my code. Is __alignof__( ::java::lang::Object ) the same under 3.4 and 4.0 in the first place? My fixes were to parse more attributes, not less. So this has to be unrelated to my patches. I suggest you file a bugreport in Bugzilla, and mark it as ABI breaking. It should get fixed before 4.0 gets out. -- Giovanni Bajo
Re: GCC 4.0 Status Report (2005-04-05)
Mark Mitchell <[EMAIL PROTECTED]> wrote: >> I've attached a revised summary of the critical bugs open against >> 4.0. The good news is that there are fewer than last week. Earlier today, Andrew Haley posted a small C++ snippet showing an ABI change affecting gcj on PPC32: http://gcc.gnu.org/ml/gcc/2005-04/msg00139.html I hope he'll open a PR soon, but you probably want to consider this for 4.0. Giovanni Bajo
Re: GCC 4.0 Status Report (2005-04-05)
Mark Mitchell <[EMAIL PROTECTED]> wrote: >>> Earlier today, Andrew Haley posted a small C++ snippet showing an ABI >>> change >>> affecting gcj on PPC32: >>> http://gcc.gnu.org/ml/gcc/2005-04/msg00139.html >>> >>> I hope he'll open a PR soon, but you probably want to consider this >>> for 4.0. >> >> >> Note it also effects all targets too by shown by my testcase. > > Please put this into a PR. This is now PR 20763. I took the liberty of CC'ing you in it. -- Giovanni Bajo
Re: Q: C++ FE emitting assignments to global read-only symbols?
Dale Johannesen <[EMAIL PROTECTED]> wrote: >> I do think the C++ FE needs fixing before Diego's change gets merged, >> though. I can make the change, but not instantly. If someone files >> a PR, and assigns to me, I'll get to it at some not-too-distant >> point. > > It would be good to have a way to mark things as "write once, then > readonly" IMO. > It's very common, and you can do some of the same optimizations on > such things > that you can do on true Readonly objects. We had this once, it was called RTX_UNCHANGING_P, and it was a big mess. Progressively, we have been removing TREE_READONLY from C++ const variables (which are "write once" from the GCC IL point of view), and this is another instance of the same problem. We probably need a better way to describe C++ constructors, maybe something like WRITEONCE_EXPR which is a MODIFY_EXPR with a READONLY on its lhs, and which is supposed by the frontends when initialing such variables. Giovanni Bajo
Re: GCC 4.0 RC1 Available
Andrew Haley <[EMAIL PROTECTED]> wrote: > There was. We are now, for the first time ever, in a position where > we can run a large number of big Java applications using entirely free > software. This is a really great news! So great that I wonder why changes.html does not mention it (and news.html as well). Would you please prepare a patch about this? -- Giovanni Bajo
Re: Problem with weak_alias and strong_alias in gcc-4.1.0 with MIPS...
Steven J. Hill <[EMAIL PROTECTED]> wrote:
> ../sysdeps/ieee754/dbl-64/s_isinf.c:29: error: 'isinf' aliased to
> undefined symbol '__isinf'
> ../sysdeps/ieee754/dbl-64/s_isinf.c:31: error: '__isinfl' aliased
> to undefined symbol '__isinf'
> ../sysdeps/ieee754/dbl-64/s_isinf.c:32: error: 'isinfl' aliased to
> undefined symbol '__isinf'
>
> I am attempting to try and figure out what changed so drastically to
> cause this. I also looked in GCC and glibc Bugzilla databases, but did
> not find anything addressing this problem. Has anyone seen this
> behavior? Thanks.
http://gcc.gnu.org/gcc-4.0/changes.html
Quote:
Given __attribute__((alias("target"))) it is now an error if target is not a
symbol, defined in the same translation unit. This also applies to aliases
created by #pragma weak alias=target. This is because it's meaningless to
define an alias to an undefined symbol. On Solaris, the native assembler would
have caught this error, but GNU as does not.
Giovanni Bajo
GCC 3.3 status
Hello Gaby, do you still confirm the release date which was last reported here: http://gcc.gnu.org/ml/gcc/2005-01/msg01253.html that is, will GCC 3.3.6 released on April, 30th? And will it be the last release of the GCC 3.3 series? Thanks, Giovanni Bajo
Re: http://gcc.gnu.org/gcc-3.4/changes.html
Gerald Pfeifer <[EMAIL PROTECTED]> wrote: >> Here is a unified diff for the proposed change (I think). > > Johan, Giovanni, I just noticed that this one apparently feel trough > the cracks? > > I had assumed that Giovanni would just go ahead an apply it since he's > an expert in that area and the patch even was rather short, but I do > not see it in CVS, so I just committed it. I either forgot about it or waited for an approval. Either way, thank you for taking care of this! Giovanni Bajo
Re: GCC 4.1: Buildable on GHz machines only?
Lars Segerlund <[EMAIL PROTECTED]> wrote: > I have to agree with Richard's assessment, gcc is currently on the > verge of being unusable in many instances. > If you have a lot of software to build and have to do complete > rebuilds it's painful, the binutils guys have a 3x speedup patch > coming up, but every time there is a speedup it gets eaten up. This is simply not true. Most of the benchmarks we have seen posted to the gcc mailing lists show that GCC4 can be much faster than GCC3 (especially on C++ code). There are of course also regressions, and we are not trying to hide them. Did you *ever* provide a preprocessed source code which shows a compile-time regression? If not, please do NOT hesitate! Post it in Bugzilla. People that did it in the past are mostly satisfied by how GCC developers improved things for them. Otherwise, I do not want to sound rude, but your posts seem more like trolling to me. I am *ready* to admit that GCC4 is much slower than GCC3 or GCC2, but I would like to do this in front of real measurable data, not just random complaints and told legends. Thus, I am really awaiting your preprocessed testcases which prove your points. Please. Giovanni Bajo
Re: GCC 4.1: Buildable on GHz machines only?
Jason Thorpe <[EMAIL PROTECTED]> wrote: >> Maybe the older platform should stick to the older compiler then, >> if it is too slow to support the kind of compiler that modern >> systems need. > > This is an unreasonable request. Consider NetBSD, which runs on new > and old hardware. The OS continues to evolve, and that often > requires adopting newer compilers (so e.g. other language features > can be used in the base OS). > > The GCC performance issue is not new. It seems to come up every so > often... last time I recall a discussion on the topic, it was thought > that the new memory allocator (needed for pch) was cause cache-thrash > (what was the resolution of that discussion, anyway?) There is no outcome, because it is just the Nth legend. Like people say "I believe GCC is slow because of pointer indirection" or stuff like that. Please, provide preprocessed sources and we *will* analyze them. Just file a bugreport in Bugzilla, it took 10 minutes of your time. Giovanni Bajo
Re: GCC 4.1: Buildable on GHz machines only?
Richard Earnshaw <[EMAIL PROTECTED]> wrote: >> The GCC build times are not unreasonable compared to other, >> commercial compilers with similar functionality. And the GCC >> developers >> ave plans to address inefficiencies -- GCC 4.0 often is faster than >> GCC >> 3.4. > > If you are going to make sweeping statements like this you need to > back them up with hard data. It is surely faster for C++ code thanks to the work done by Codesourcery on the lexing upfront and the name lookup. "Faster" here means 20-30% faster, so it's not 1% or something like that. There are many posts on gcc@ that show this, I can dig them up in the archive for you if you want, but I'm sure you can use google as well as I do. Two of them are very recente (see Karel Gardas' post on this thread, and the recent benchmark posted by Rene Rebe). Giovanni Bajo
Re: GCC 4.1: Buildable on GHz machines only?
Ian Lance Taylor wrote: >> Except it's not just bootstrapping GCC. It's everything. When the >> NetBSD Project switched from 2.95.3 to 3.3, we had a noticeably >> increase in time to do the "daily" builds because the 3.3 compiler >> was so much slower at compiling the same OS source code. And we're >> talking almost entirely C code, here. > > Well, there are two different issues. Matt was originally talking > about bootstrap time, at least that is how I took it. You are talking > about speed of compilation. The issues are not unrelated, but they > are not the same. > > The gcc developers have done a lot of work on speeding up the compiler > for 3.4 and 4.0, with some success. On many specific test cases, 4.0 > is faster than 3.3 and even 2.95. The way to help this process along > is to report bugs at http://gcc.gnu.org/bugzilla. > > In particular, if you provide a set of preprocessed .i files, from, > say, sys, libc, or libcrypto, whichever seems worst, and open a gcc PR > about them, that would be a great baseline for measuring speed of > compilation, in a way that particularly matters to NetBSD developers. I would also like to note that I *myself* requested preprocessed source code to NetBSD developers at least 6 times in the past 2 years. I am sure Andrew Pinski did too, a comparable amound of times. These requests, as far as I can understand, were never answered. This also helped building up a stereotype of the average NetBSD developer being "just a GCC whine troll". I am sure this is *far* from true, but I would love to see NetBSD developers *collaborating* with us, especially since what we are asking (filing bug reports with preprocessed sources) cannot take more than 1-2 hours of their time. Giovanni Bajo
Re: GCC 4.1: Buildable on GHz machines only?
Jason Thorpe <[EMAIL PROTECTED]> wrote: >> I would also like to note that I *myself* requested preprocessed >> source code to >> NetBSD developers at least 6 times in the past 2 years. I am sure >> Andrew Pinski >> did too, a comparable amound of times. These requests, as far as I >> can understand, were never answered. This also helped building up a >> stereotype of >> the average NetBSD developer being "just a GCC whine troll". > > While I have not had much time for a quite a while to work on GCC > myself, I am listed as NetBSD maintainer... you can always drop me a > note directly when this sort of thing happens. Thanks! Are you then going to file in Bugzilla some preprocessed sources that show the 2.95 -> 3.3 slowdown experimented by NetBSD folks? Giovanni Bajo
Re: volatile semantics
Mike Stump <[EMAIL PROTECTED]> wrote:
> int avail;
> int main() {
>while (*(volatile int *)&avail == 0)
> continue;
>return 0;
> }
>
>
> Ok, so, the question is, should gcc produce code that infinitely
> loops, or should it be obligated to actually fetch from memory?
> Hint, 3.3 fetched.
I agree it should fetch. Did you try -fno-strict-aliasing? Open a bugreport,
I'd say.
Giovanni Bajo
Re: big slowdown gcc 3.4.3 vs gcc 3.3.4 (64 bit)
Kenneth P.. Massey wrote: > The code below runs significantly slower when compiled in 64 bit with > 3.4.3 than > it does in 3.3.4, and both are significantly slower than a 32 bit > compile. Thanks for the report. Would you please open a bugreport in Bugzilla? -- Giovanni Bajo
Re: GCC 4.0.0 Performance Regressions?
Jason Bucata <[EMAIL PROTECTED]> wrote:
> Is anybody collecting information on performance regressions in 4.0.0
> (vs.
> 3.4.3)? I've got some results on POVRAY and BYTEmark, and BYTEmark
> saw some performance regression, particularly with profiled
> optimization (-fprofile-{generate,use}):
> http://forums.gentoo.org/viewtopic-t-329765.html
You should try and isolate a single BYTEmark test which shows the biggest
regression. It's better if you manage to pack the whole test as a single
preprocessed source file. Theoretically, this file should be compilable and
linkable, and the resulting binary should run for a while doing computations.
With this kind of help, we can analyze the regression and see why it's slower
with 4.0.0.
Giovanni Bajo
Re: GCC 4.0.0 Performance Regressions?
Jason Bucata <[EMAIL PROTECTED]> wrote: >> You should try and isolate a single BYTEmark test which shows the >> biggest regression. It's better if you manage to pack the whole test >> as a single preprocessed source file. Theoretically, this file >> should be compilable and linkable, and the resulting binary should >> run for a while doing computations. >> >> With this kind of help, we can analyze the regression and see why >> it's slower with 4.0.0. > > It was rather time-consuming but I managed to do it. I picked the > numsort benchmark which had a serious regression: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21485 Many, many thanks! Giovanni Bajo
Re: GCC 3.4.4 RC1
Etienne Lorrain <[EMAIL PROTECTED]> wrote: > Some of those problem may also exist in GCC-4.0 because this > version (and the 4.1 I tested) gives me an increase of 60% of the > code size compared to 3.4.3. This is a serious regression which should be submitted in Bugzilla. Would you please take care of that? It is sufficient to provide a single preprocessed source which shows the code size increase in compilation. GCC4 still needs some tuning for -Os. Thanks! -- Giovanni Bajo
Re: GCC 3.4.4 RC1
Etienne Lorrain <[EMAIL PROTECTED]> wrote: > If I compile that with GCC-3.4, I get: > > $ size tmp.o > textdata bss dec hex filename > 243 0 0 243 f3 tmp.o > > With GCC-4.0: > > $ size tmp.o > textdata bss dec hex filename > 387 0 0 387 183 tmp.o > > Can someone confirm the problem first? I can confirm that this function shows a regression simply with -Os, on x86-linux: GCC 3.4.3: textdata bss dec hex filename 194 0 0 194 c2 test.o GCC 4.1.0 CVS 20050323 textdata bss dec hex filename 280 0 0 280 118 test.o So it's a 44% increase. Definitely worth a bugreport in Bugzilla! -- Giovanni Bajo
Re: Proposed resolution to aliasing issue.
Mark Mitchell <[EMAIL PROTECTED]> wrote:
> Our proposed approach is to -- by default -- assume that "g" may
> access all of "b". However, in the event that the corresponding parameter to
> "g" has an attribute (name TBD, possibly the same as the one that
> appears in Danny's recent patch), then we may assume that "g" (and its
> callees) do not use the pointer to obtain access to any fields of "b".
>
> For example:
>
>void g(A *p __attribute__((X)));
>
>void f() {
> B b;
> g(&b.a); /* Compiler may assume the rest of b is not accessed
> in "g". */
>}
It is not clear if you are speaking here of the C language or GENERIC, but
anyway I'll comment.
Can the meaning of the attribute be reversed? I would like it to mark places
where upcasts can happen. In any code base you may pick up, there are probably
just a couple of points where you'd need to say "I'll upcast this pointer",
while *all* the other uses are ok as they are. So I guess it makes sense to
have the default *reversed*. Then, you can make TBAA disabled by default for
the C and C++ language.
After all, there is absolutely no point in enabling it by default if, to make
it useful, you have to decorate billions of function declarations. And if it is
disabled by default, the meaning of the attribute can be reversed without any
risk. You can then state in the documentation how to use the attribute if one
really needs TBAA.
So to recap, my proposal is:
- For the C and the C++ frontend, do not enable TBAA through -Ox, just keep it
a separate option (-ftree-tbaa).
- Add __attribute__((upcast)) that can be used to decorate pointers in
parameter declarations which might be subject to upcasting during the
function's body execution.
- For C++ frontend, we can have a -fpod-upcast which adds attribute upcast
automatically for all pointers to POD types.
- Explain in the documentation that -ftree-tbaa is risky for C/C++ unless the
code base is audited and __attribute__((upcast)) added wherever appropriate.
- For the Java/Fortran/Ada frontend, probably TBAA can be on by default at -Ox,
but I dunno.
I'm positive that for C++ there would be zero need for manual decoration in,
say, a whole OS distribution (Qt, KDE, Boost, and whatnot) if we use
"-ftree-tbaa -fpod-upcast".
Giovanni Bajo
Re: GCC-4.0 vs GCC-3.3.6 ia32 -Os: code size increase from 261 to 5339 bytes
Etienne Lorrain <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED]:~/projet/gujin$ gcc -Os tst.c -c -o tst.o && size tst.o >textdata bss dec hex filename > 261 0 0 261 105 tst.o > [EMAIL PROTECTED]:~/projet/gujin$ ../toolchain/bin/gcc -Os tst.c -c -o tst.o && > size tst.o >textdata bss dec hex filename >5339 0 0533914db tst.o > [EMAIL PROTECTED]:~/projet/gujin$ It's another issue with SRA and -Os. With an old 4.1, I have: $ ./xgcc -c -Os -B. btst.c && size btst.o textdata bss dec hex filename 5339 0 0533914db btst.o $ ./xgcc -c -Os -fno-tree-sra -B. btst.c && size btst.o textdata bss dec hex filename 224 0 0 224 e0 btst.o So we're actually better than 3.3, after we disable -ftree-sra. I guess SRA should be tuned (disabled?) for -Os. Please, do file a bugreport. -- Giovanni Bajo
Re: GCC-4.0 vs GCC-3.3.6 ia32 -Os: code size increase from 261 to5339 bytes
Daniel Berlin <[EMAIL PROTECTED]> wrote: >> $ ./xgcc -c -Os -B. btst.c && size btst.o >>textdata bss dec hex filename >>5339 0 0533914db btst.o >> $ ./xgcc -c -Os -fno-tree-sra -B. btst.c && size btst.o >>textdata bss dec hex filename >> 224 0 0 224 e0 btst.o >> >> So we're actually better than 3.3, after we disable -ftree-sra. I >> guess SRA should be tuned (disabled?) for -Os. > > Structure aliasing should be able to make up for turning off SRA, i'm > guessing, at least as far as propagating constants and DCE is > concerned. > > You could test this by seeing if -fno-tree-sra -fno-tree-salias > produces > an increased code size over the above. Not really: with -fno-tree-salias I get exactly the same result (224 bytes). Giovanni Bajo
hidden enum constants (Was: Compiling GCC with g++: a report)
Zack Weinberg <[EMAIL PROTECTED]> wrote:
>>> This doesn't do what I want at all. The goal is to make the *symbolic
>>> enumeration constants* inaccessible to most code.
>>
> ...
>> If it's OK to have the enums in a header, provided you can't *use*
them...
>>
>> enum {
>> #ifdef TVQ_AUTHORITATIVE_ENUMS
>> TVQ_FOO1,
>> TVQ_FOO2,
>> TVQ_FOO3,
>> TVQ_NUM_ENTRIES,
>> #endif
>> TVQ_INT_SIZER = 32767;
>> } TheValQuux;
>>
>> This won't stop a suitably enthusiastic programmer from getting to
>> them anyway, but that's always the case.
>
> Ooh, I like this one for enum machine_mode.
I think this is an ODR failure for C++ and I suspect program-at-a-time would
flag it with an error. So even this solution to hide enum constants (a
legitimate design request) does not appear to be C++ compatible to me.
--
Giovanni Bajo
Removal of 4.0.0 last minute page from Wiki?
Mark, is it OK to remove the link "Last-Minute Requests for 4.0.0" from the Wiki main page? The page is obviously unneded there. If you want, we can keep the link somewhere else (like collected in a page "obsolete misc pages"). -- Giovanni Bajo
Re: What is wrong with Bugzilla? [Was: Re: GCC and Floating-Point]
Michael Veksler <[EMAIL PROTECTED]> wrote:
> Unfortunately, this is not 100% correct. Recently I have filed several
> duplicates, *after* searching Bugzilla.
That is not a problem. Bugmasters are there exactly for that. We realize that
finding duplicates can be very hard (in fact, sometimes duplicates are
acknowledged as such only after a fix appears), so that is our work. We just
ask users for some *basic* duplicate checking, and I think most users do that
before filing bugreports. So it's ok.
> 3. Nontrivial search of GCC Bugzilla are, sometimes,
>extremely slow (over a minute).
3 could be worked on (Daniel?)
> Technically speaking, these are not GCC bugs. However, from
> user's POV they *are* GCC bugs. This mismatch between user
> and developer perceptions is not very healthy and may inhibit
> other PRs. Maybe developers should be more open to "fixing"
> things that are not purely GCC bugs?
Maybe. But I don't think people don't file bugreports because of this. In every
software company I have been working on there has always been some debates
about bugreports ("it's your code's fault" -- "no, it's yours"), I expect GCC
users to know/expect this. Anyway, we are speaking of a really minority of the
bug reports we get. Most of the bugreports filed *are* related to GCC, and
among those that are not, most are *obviously* so (in that, people realize
immediately it's not GCC's fault).
> [2] GCC could implement a better error message.
This is a bug, too. You can file a PR in Bugzilla explictly asking for a more
informative error message.
Giovanni Bajo
Re: What is wrong with Bugzilla? [Was: Re: GCC and Floating-Point]
Vincent Lefevre <[EMAIL PROTECTED]> wrote: >> At this point, I wonder what is wrong with Bugzilla, that those >> programmers don't fill a proper bug report. If there is a problem >> with GCC, that is so annoying to somebody, I think that at least >> developers could be informed about it via their standard channels of >> communication. > > Perhaps because GCC developers think that GCC isn't buggy when the > processor doesn't do the job for them? (I'm thinking of bug 323.) You are mistaken, we think GCC isn't buggy about 323 because the C/C++ standards do not tell us to do better than this. If you have higher expectations about floating point and C/C++, you should file a bugreport against the C/C++ standards. Really, we can't make everybody happy. The best we can do is to adhere the international well-known ISO/ANSI standards. Giovanni Bajo
Use of check_vect() in vectorizer testsuite
Hello, I have some questions about the use of check_vect() in the vectorizer testsuite: 1) All the ifcvt tests (vect-ifcvt*) seem to require SSE2 capability to be vectorized but they do not call check_vect(). Is this a bug? They surely fail on my platform (which does not have SSE2). 2) The same applies for a vect_int test, vect-dv-2.c. I assume also vect_int tests require SSE2 capability and thus should call check_vect()? Thanks, Giovanni Bajo
Re: Use of check_vect() in vectorizer testsuite
Devang Patel <[EMAIL PROTECTED]> wrote: > check_vect() is used to test whether to run the test or not. Now, > vect.exp does the job more efficiently. > > 29 # If the target system supports vector instructions, the > default action > 30 # for a test is 'run', otherwise it's 'compile'. Save > current default. > 31 # Executing vector instructions on a system without hardware > vector support > 32 # is also disabled by a call to check_vect, but disabling > execution here is > 33 # more efficient. > > > And dg-require-... should control whether this test should be enabled > or not. So depending upon the failure (runtime or compiler not > vectorizing loops), you want to update appropriate code block in > vect.exp for your platform. The point is that my target is i686-pc-linux-gnu, which supports vector instruction (through -msse2), but whether the instructions can actually be run or not depends on the given processor (e.g. Pentium 3 vs Pentium 4). Even if my processor cannot *execute* the vectorized tests, I would still like to test whether vectorization succeeds or not (that is, at least as compile-time tests). So, the point is that you cannot select between compile-time/run-time based on a target triplet check, at least for this target. What do you suggest? All the other tests use check_vect() exactly for this reason, as far as I can see, so it looks to me that the sensible thing to do is to use check_vect there as well. For an example of the failures, see for instance: http://gcc.gnu.org/ml/gcc-testresults/2005-06/msg00553.html (which is Diego's tester). -- Giovanni Bajo
Re: Use of check_vect() in vectorizer testsuite
Janis Johnson <[EMAIL PROTECTED]> wrote: > It sounds as if there should be a check in target-supports.exp for > SSE2 support that determines whether the default test action is 'run' > or 'compile' for i686 targets. I am not able to code TCL/Expect. Instead, I can easily provide a patch to make the few missing testcases call check_vect(), as the rest of the testsuite does. This would shut down the bogus regressions, while a more correct solution is being developed. Would such a patch be ok? -- Giovanni Bajo
Re: Getting started with contributing
Lee Millward <[EMAIL PROTECTED]> wrote: > I have spent the last few weeks reading the gcc-patches mailing list > and the documentation available on GCC from the Wiki and various other > documents I have found on the Internet to try and get a feel for how > everything works. I also have the latest CVS code and have spent time > reading through the source to become familiar with the coding > conventions in use. I've read through the "beginner" GCC projects on > the website and would like to hear peoples opinion on how useful > submitting patches for some of the these projects would be. Some of > the work being carried out and posted on the gcc-patches mailing list > makes those projects seem insignificant in comparision. There are a couple of ongoing transitions that might be carried out by beginners. For instance, we are in the process of converting all calls to "abort()" to calls to gcc_assert()/gcc_unreachable(). Or we are trying to convert all the VARRAY data structures into VEC data structures. You might have seen some of these patches in gcc-patches. I think those are a good fit for a beginner. Also, remember to file papers for copyright assignment to the FSF, which is a prerequisite for accepting any patch. Giovanni Bajo
Question about new warning system
Hello DJ, I'm updating a piece of code of the C++ frontend which involves a warning, so I was planning on adding the correct warning option to it. The original code is the following: if (warn_missing_braces) warning (0, "missing braces around initializer"); So, what is the correct way of fixing this: [1] if (warn_missing_braces) warning (OPT_Wmissing_braces, "missing braces around initializer"); [2] if (OPT_Wmissing_braces) warning (OPT_Wmissing_braces, "missing braces around initializer"); [3] warning (OPT_Wmissing_braces, "missing braces around initializer"); What is the difference between [1], [2], [3]? Thanks, -- Giovanni Bajo
Re: Question about new warning system
DJ Delorie <[EMAIL PROTECTED]> wrote: >> if (OPT_Wmissing_braces) >>warning (OPT_Wmissing_braces, "missing braces around >> initializer"); > > FYI OPT_Wmissing_braces is an enum constant; it will always be nonzero. So, I assume this patch is wrong in this regard: http://gcc.gnu.org/ml/gcc-cvs/2005-06/msg00392.html >> [3] >> warning (OPT_Wmissing_braces, "missing braces around initializer"); > > That is what we decided to do. > > Note, however, if the logic required to determine if a warning is > warranted is sufficiently complex, *also* checking the variable is > considered an optimization: OK, thanks! -- Giovanni Bajo
Re: Question about new warning system
DJ Delorie <[EMAIL PROTECTED]> wrote: >> So, I assume this patch is wrong in this regard: >> http://gcc.gnu.org/ml/gcc-cvs/2005-06/msg00392.html > > Yes, it's wrong in that way. Gaby, can you please fix it then? -- Giovanni Bajo
Re: Question about new warning system
Nathan Sidwell <[EMAIL PROTECTED]> wrote:
> I'm inclined to agree it is confusing. especially as in one place one has
to
> write warn_ and in the other place one writes OPT_W. It'd be
> nice if one just wrote
> if (warn_foo && frobbed)
> warning ("foo is frobbed");
>
> I don't care if it's spelt warn_foo, OPT_Wfoo, warning_p(foo) or whatever,
> so long as it's spelt only one way. The 'warning (OPT_Wfoo, ...)' syntax
> helps only where there is no conditional before the warning -- how often
> does that occur? The way it currently is, one runs the risk of writing
> if (warn_c_cast
>&& .
> && .
> && .)
> warning (OPT_Wconst_cast, ...)
Actually, the point is that you *never* need to explicitally name the
"warn_" variable unless you are optimizing. In other words, code which
presently is:
if (warn_foo
&& frobbed)
warning (0, "foo is frobbed");
should be replaced with:
if (frobbed)
warning (OPT_Wfoo, "foo is frobbed");
You need to pass the option to warning() also for another reason: we want to
be able to optionally print which flag can be used to disable each warning,
so warning() has to be smarter than it used to be.
--
Giovanni Bajo
Re: In current gcc trunk: warning: dereferencing type-punned pointer will break strict-aliasing rules
Nathan Sidwell <[EMAIL PROTECTED]> wrote: > Christian Joensson wrote: >> I'd just like to ask if this is noticed: >> >> /usr/local/src/trunk/gcc/gcc/unwind-dw2.c:324: warning: dereferencing >> type-punned pointer will break strict-aliasing rules >> /usr/local/src/trunk/gcc/gcc/unwind-dw2.c:789: warning: dereferencing >> type-punned pointer will break strict-aliasing rules >> /usr/local/src/trunk/gcc/gcc/unwind-dw2.c:1005: warning: >> dereferencing type-punned pointer will break strict-aliasing rules >> /usr/local/src/trunk/gcc/gcc/unwind-dw2-fde.c:1024: warning: >> dereferencing type-punned pointer will break strict-aliasing rules >> /usr/local/src/trunk/gcc/gcc/unwind-dw2-fde-glibc.c:393: warning: >> dereferencing type-punned pointer will break strict-aliasing rules > > I had not noticed this, but looking at the first one it must have > been caused by my patch to the type punning warning. It also appears > to be a correct warning, in that we are breaking aliasing. I see also these in my builds: ../../../gcc/libmudflap/mf-runtime.c:320: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:323: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:326: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:329: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:333: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:336: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:339: warning: dereferencing type-punned pointer will break strict-aliasing rules ../../../gcc/libmudflap/mf-runtime.c:342: warning: dereferencing type-punned pointer will break strict-aliasing rules The code is accessing a variable of enum type through an unsigned pointer. Giovanni Bajo
Re: Fixing Bugs (Was: A Suggestion for Release Testing)
Scott Robert Ladd <[EMAIL PROTECTED]> wrote: > Consider, as an example, the bug/non-bug at http://gcc.gnu.org/PR323, > which was a matter of recent discussion on this list. Some rather > respectable people (e.g., Vincent Lefèvre) consider this a bug, and > have proposed solutions. Yet here's a quote from an earlier message by > Giovanni Bajo. > [...] First of all, I would consider polite to CC: me on the mail if you quote and debate my statements. > The ISO Standard doesn't prevent GCC from being *better* than > specified, does it? Are we somehow breaking ISO compliance by doing > math right? Is it so wrong to try and fix a problem that frustrates > many people and makes GCC look bad? Where exactly do I say that it is wrong to provide a patch that makes GCC better in this regard? As a bugmaster, I just decided to consider this not a bug, in the strictest meaning of "bug". If you want to file in Bugzilla an enhancement proposal about adding options/modes about higher FPU precision, I would not object. Also, it seems you have the wrong belief that, if bug 323 were confirmed in Bugzilla, a patch would automatically appear. I think the two events are totally unrelated, especially for an issue which has been debated so much in the past years, and where most people have already a formed opinion on the matter. > With the attitude shown by Giovanni, there's really no point in > submitting a patch, is there? Dozens of people have reported this > problem, potential solutions exist, but any patch is going to be > ignored because the bug isn't considered a bug by the Powers That Be. You seem to believe that a patch can be accepted in GCC only if it fixes a bug. That is wrong: a valid patch can also add a new feature. While it is probably hard to convince the Powers That Be (which, by the way, are surely not me) that the default setting of GCC should be whatever Bug 323 requests, it is much much easier that a patch adding a new command line option to request higher FP accuracy be reviewed and accepted. Of course, people would have to *see* such a patch. And nobody is blocking people from writing it. I hope to have clarified my position. Giovanni Bajo
PR 14814
Jeff, g++.dg/tree-ssa/pr14814.C has been failing from the first day it was added. It is unclear to me what happened in detail, but in the PR you suggest to XFAIL the testcase. That would be fine: would you please take care of that? Also, notice that there is a typo in the ChangeLog entry for this testcase. It reads: 2005-05-17 Jeff Law <...> * g++.dg/tree-ssa/pr18414.C: New test. * gcc.dg/tree-ssa/pr18414.C: New test. while the correct PR number is "14814". Would you please also fix this? Thanks, Giovanni Bajo
Re: Bug in transparent union handling?
Richard Henderson <[EMAIL PROTECTED]> wrote: > This needs to use a VIEW_CONVERT_EXPR, at minimum. What about a compound literal instead? Giovanni Bajo
Re: Reporting bugs: there is nothing to gain in frustrating reporters
Roberto Bagnara <[EMAIL PROTECTED]> wrote: > 1) I submit a bug report; > 2) someone looks at it superficially, too superficially, and > posts a comment that tends to deny there is a problem; > 3) I and/or someone else explain that the problem is indeed > there, possibly citing the points of the standards that > are being violated; > 4) the person who said the bug was not (exactly) a bug does > not even care to reply, but the superficial comments > remain there, probably killing the bug report. While I agree that it can happen to make a too superficial comment on a bug (I surely had done this in the past, and Andrew seems to do this very often), I believe that this does not spoil or kill the bug report itself, once it was agreed that there is indeed a bug. Surely, it does annoy the reporter though, which is a serious problem. > I wonder what is the rationale here. Discouraging bug > reporters may be an effective way to avoid bug reports pile up, > but this is certainly not good for GCC. I totally agree here. I believe Mark already asked us (bugmasters) to be more polite in their work, and I believe that another official statement in this direction would help. > My advice to people filtering bug reports is: if you only had > time to look at the issue superficially, either do not post > any comment or be prepared to continue the discussion on more > serious grounds if the reporter or someone else comes back > by offering more insight and/or precise clauses of the > relevant standards. Agreed. But keep in mind that it is not necessary to reply: once the bug is open and confirmed, the last comment "wins", in a way. If the bugmaster wanted to close it, he would just do it, so an objection in a comment does not make the bug invalid per se. -- Giovanni Bajo
Re: Bug in transparent union handling?
Richard Henderson <[EMAIL PROTECTED]> wrote: >>> This needs to use a VIEW_CONVERT_EXPR, at minimum. >> >> What about a compound literal instead? > > I suppose. Why? Nothing specifically. I just believe it is a cleaner way to transform the argument into an aggregate, casts are ugly. Giovanni Bajo
Your rtti.c changes broke some obj-c++ tests
Nathan, I see some failures in the testsuite which appear to be related by your recent changes to rtti.c (VECification). For instance: FAIL: obj-c++.dg/basic.mm (test for excess errors) Excess errors:/home/rasky/gcc/mainline/gcc/libstdc++-v3/libsupc++/exception:55: internal compiler error: vector VEC(tinfo_s,base) index domain error, in get_tinfo_decl at cp/rtti.c:373 Would you please check and possibly fix this? Thanks, Giovanni Bajo
Re: How to write testcase with two warnings on one line?
Feng Wang <[EMAIL PROTECTED]> wrote: > I want to write a testcase. The compiler gives two separated warnings on one > statement. How to write this with Dejagnu? http://gcc.gnu.org/wiki/HowToPrepareATestcase -- Giovanni Bajo
Re: toplevel bootstrap (stage 2 project)
Paolo Bonzini <[EMAIL PROTECTED]> wrote: > To recap, toplevel bootstrap has several aims, including: >[...] I suggest you to add this to the Wiki. > To enable toplevel bootstrap, just configure with --enable-bootstrap. > Then, "make" will do more or less what "make bubblestrap" used to do: What does "./configure --enable-botstrap; make bootstrap" do? > It supports all the bells and whistles like bubblestraps and restageN, > which help during development. "make restrap" is not supported. "make > restageN" is called "make all-stageN", and there is also "make > all-stageN-gcc" to rebuild gcc only. It would help also if you add to the wiki explanation of what exactly all these options do. Especially bubblestrap vs quickstrap vs restrap. Thanks! -- Giovanni Bajo
Re: toplevel bootstrap (stage 2 project)
Gerald Pfeifer <[EMAIL PROTECTED]> wrote: >> It would help also if you add to the wiki explanation of what exactly all >> these options do. Especially bubblestrap vs quickstrap vs restrap. > > Why to the WIki?? This should be part of the regular documentation, > and if anything is to improve, the improvements should be made there > instead of having that on the Wiki (or, even worse, causing duplication). Well, because Wiki is more attractive to people writing documentation for several reasons (faster than writing a HTML/TeX patch and submitting it for review, etc.). Maybe we should think if we want to use the Wiki as our rapid documentation prototyping: people could write documentation there for review, be refined by others, and eventually converted to real TeX documentation. -- Giovanni Bajo
Re: toplevel bootstrap (stage 2 project)
Daniel Berlin <[EMAIL PROTECTED]> wrote: >> Well, because Wiki is more attractive to people writing >> documentation for several reasons (faster than writing a HTML/TeX >> patch and submitting it for review, etc.). Maybe we should think if >> we want to use the Wiki as our rapid documentation prototyping: >> people could write documentation there for review, be refined by >> others, and eventually converted to real TeX documentation. > > This is what i did with the decl hierarchy documentation i submitted > as part of the decl cleanup patch. > > The Texinfo version took significantly longer than the wiki portion, > but it was mainly just mechanical formatting, etc, where wiki knows what > to do automatically or with a trivial command and Texinfo doesn't. I believe we could conceive something to convert raw wiki text into texinfo with our commands. It would handle the boring part of the conversion. Giovanni Bajo
Re: G++ and ISO C++
Mirza <[EMAIL PROTECTED]> wrote: > Can someone point me to list of ISO C++ vs. g++ incompatibilities. There are very few large issues at this point. The only big feature missing is "export", then it's a bunch of relatively minor nits (access checking in friend declarations within templates, correct semantic for old-style access declarations vs using declarations, etc.), plus of course the usual bag of bugs. I am not aware of any official list though. Giovanni Bajo
Re: [RFH] - Less than optimal code compiling 252.eon -O2 for x86
Joe Buck <[EMAIL PROTECTED]> wrote: >>> I'd tend to agree. I'd rather see the option go away than linger on >>> if the option is no longer useful. >> >> I wouldn't mind that, but I'd also like to point out that there are >> Makefiles out there which hard-code things like -fforce-mem. Do we want >> to keep the option as a stub to avoid breaking them? > > It could produce a "deprecated" or "obsolete" warning for 4.1, and then be > removed for 4.2. Personally, I don't see a point. -fforce-mem is just an optimization option which does not affect the semantic of the program in any way. If we remove it, people would need to just drop it from their Makefiles. There is no source code adjustment required (which would justify the deprecation cycle). Or convert it to a noop as Bernd suggested. -- Giovanni Bajo
Re: PARM_DECL of DECL_SIZE 0, but TYPE_SIZE of 96 bits
Daniel Berlin <[EMAIL PROTECTED]> wrote: > So we've got a parm decl that if you ask it for the DECL_SIZE, says 0, > but has a TYPE_SIZE of 12 bytes, and we access fields in it, etc. I am not sure of what the exact relations between DECL_SIZE and TYPE_SIZE are, but probably some verification could be done, eg, at gimplification time, rather than waiting for latent bugs in optimizers to produce wrong code? -- Giovanni Bajo
Re: potential simple loop optimization assistance strategy?
Paul Schlie <[EMAIL PROTECTED]> wrote:
> Where then the programmer could then choose
> to warrant it by preconditioning the loop:
>
> assert((x < y) && ((y - x) % 4)); // which could throw an exception.
>
> for ((i = x; i < y; i++){ ... }
There has been some opposition in the past about allowing conditions in
asserts to be used as hints to the optimizers. In fact, I would like to know
if there is a current statement of purpose about this. That is, would there
be strong oppositions to patches doing this?
--
Giovanni Bajo
Re: potential simple loop optimization assistance strategy?
Diego Novillo <[EMAIL PROTECTED]> wrote:
>> There has been some opposition in the past about allowing conditions in
>> asserts to be used as hints to the optimizers. In fact, I would like to
>> know if there is a current statement of purpose about this. That is,
would
>> there be strong oppositions to patches doing this?
>>
> VRP naturally takes advantage of assert (though not in some
> occassions involving unsigned types). Try:
>
> #include
>
> foo (int i)
> {
> assert (i != 0);
> if (i == 0)
> return 3;
>
> return 2;
> }
Agreed, but my point is whether we can do that when NDEBUG is defined.
--
Giovanni Bajo
Re: potential simple loop optimization assistance strategy?
Tom Tromey <[EMAIL PROTECTED]> wrote: > Giovanni> Agreed, but my point is whether we can do that when NDEBUG > Giovanni> is defined. > > I thought when NDEBUG is defined, assert expands to something like > '(void) 0' -- the original expression is no longer around. Yes, but the condition is still morally true in the code. NDEBUG is meant to speed up the generated code, and it's actually a pity that instead it *disables* some optimizations because we don't see the condition anymore. My suggestion is that assert with NDEBUG might expand to something like: if (condition) unreachable(); where unreachable is a function call marked with a special attribute saying that execution can never get there. This way the run-time check is removed from the code, but the range information can still be propagated and used. Notice that such an attribute would be needed in the first place for gcc_unreachable() in our own sources. Right now we expand it to gcc_assert(0), but we could do much better with a special attribute. Giovanni Bajo
Re: potential simple loop optimization assistance strategy?
Michael Veksler <[EMAIL PROTECTED]> wrote: > have no side effects. So if "condition" contains any side effect, > or potential side effect (e.g. through function call), then the > compiler should not generate the code for "condition". Right. Thus we can find a way to avoid generating e.g. function calls or similar things, and get information from the most basic conditions. Giovanni Bajo
Re: Can I trace the process of C++ template Instantiation?
zheng wang <[EMAIL PROTECTED]> wrote: >How can I trace the process of C++ template > Instantiation? I study Loki and some library is very > complex, so I want to see how gcc compiler instance > the template class. The source code for template processing is mostly contained in the file cp/pt.c. The instantiation happens in the function tsubst_copy_and_build. You can place a breakpoint there and see what happens within GDB. -- Giovanni Bajo
Re: Bugzilla does not let me in
Ilya Mezhirov <[EMAIL PROTECTED]> wrote: > I've got a problem: bugzilla sends me no registration e-mails. > I tried two times with different e-mail addresses and got nothing. > So I cannot report a gcj bug :( > > You've got a nice page "Reporting Bugs" that explains what needs to be > sent, but doesn't contain a word about *where* to send. That's not a > flame, just a silly user's troubles. I see you already have an account. Login is [EMAIL PROTECTED] Try logging in with the password you provided. Otherwise, I can reset the password for you. -- Giovanni Bajo
Re: some errors compiling a free program with gcc-3.2, gcc-3.4.4 and gcc-4.0.0 on i386 freebsd -5.2.
wangxiuli <[EMAIL PROTECTED]> wrote: > why? are those errors related to the version of gcc? > please help This mailing list is dedicated to the development of GCC itself. Questions about problems using GCC should generally be directed to [EMAIL PROTECTED] Anyway, this is not strictly a GCC question, but mainly a C++ question, your program is likely invalid and you do not know why. So probably the best forum to ask is some newsgroup like comp.lang.c++.moderated. -- Giovanni Bajo
Stage 2 ends?
Mark, I have a simple C++ patch which I need to clean up for submission (it makes us not print default arguments for template parameters in diagnostics, which is much requested from the Boost community). It doesn't qualify for Stage 3 though, so I would like to know what's the current status of Stage 2. As things stand now, Stage 2 ends tomorrow. Giovanni Bajo
Re: Some notes on the Wiki (was: 4.1 news item)
Gerald Pfeifer <[EMAIL PROTECTED]> wrote: > It was reviewed the very same day it was submitted: > > http://gcc.gnu.org/ml/gcc-patches/2004-06/msg00313.html > http://gcc.gnu.org/ml/gcc-patches/2004-06/msg00321.html Yes. And the review was very detailed, and suggested that I had to redone to work almost from scratch, scattering the infos across a dozen of files in both WWW and TeX format where they really belong (including Dejagnu's documentation), *plus* I could also provide the existing page as a tutorial with references. I would like to thank you and Joseph Myers for the accurate and fast review. The point is that it took me already long enough to prepare that patch, and I never had time (nor will, let me admit) to go back and redo the work in a different way. What happened next is that I started providing the link to the gcc-patches mail over IRC, and then in the list, and then in private mail. And people were thanking me for it, because it was very helpful. So, I realized that, while the improvements you suggested were legitimate and correct, that text was already very useful *the way it is* *right now*. So, it was put in the Wiki. And I know many people have read it and found it useful. If you want, you can add a plea at the bottom of the Wiki page, summing the reviews and asking volunteers to incorporate it into the documentation in the proper places. I already expressed my concerns about the way documentation patches work in other threads. I myself am uninterested in contributing documentation patches to TeX (and pretty discouraged about the WWW patches, even if I do that regularly, as you well know). Instead, I contributed many things to the Wiki. Given the way things like Wikipedia work out, I think we need to either review our documentation system, or, if there is too much politics going on with the FSF, accept the fact that the documentation *is* going to be forked, and setup a workflow to contribute stuff back from the wiki to the official documentation. My personal position is that making documentation patches *blocked* by review (as happens with code) is wrong. The worst thing it can happen is that the documentation patch is wrong, and the doc maintainer can revert it in literally seconds (using the Wiki; in minutes/hours using the TeX). Nobody is going to be blocked by this; no bootstrap will be broken; no wrong code will be generated. This ain't code. In many common cases, the documentation will be useful effectively immediatly, and typos/subtleties/formatting can be refined by others over time. -- Giovanni Bajo
Re: Some notes on the Wiki (was: 4.1 news item)
Joseph S. Myers <[EMAIL PROTECTED]> wrote: >> Nobody is going to be blocked by this; no bootstrap will be broken; no >> wrong code will be generated. This ain't code. In many common cases, the > > Wrong code will be generated when someone relies on subtly wrong > information in the documentation. It is a well-established failure mode > even on the best wikis (i.e. Wikipedia) that someone inserts subtly wrong > information because of not knowing better (or not knowing that there is > controversy among experts about which of two versions is correct) and this > does not get corrected soon if at all. That is right, but there are level of interests. The debate can be on some small detail, while the big picture is still good enough for beginners or intermediates. Having something which is possibly wrong on some subtle details is still better than having nothing at all. As I said, I am a strong sustainer of "commit now, refine later". > (b) I don't see Wikipedia edits routinely getting > reverted simply for lack of substantiating evidence. Yeah, but I widely use it and it is still very useful. It may not be 1000% correct in each word, so what? Are printed books any better? Or is there a real only truth? We're entering philosphy here. What is certain is that Wikipedia wouldn't be 1/1000th of that if there was a review process for each patch being submitted. > Perhaps the wiki could automatically send all changes to gcc-patches to > assist in review? I strongly support this (and was going to suggest this myself). I'd rather it be another list though, say wiki-patches or doc-patches, because of the amount of traffic that is going to be generated (think of all those small typo fixes, or spam reverts). -- Giovanni Bajo
[ATTN: Steering Committee] Management of new ports
Hello, there seems to be a problem with the management of new ports. - Documentation is inappropriate. There is a picky checklist to follow, but it does not cover the interesting things, that is the list of de-facto technical standards that we expect new ports to follow (with respect to incomplete transition). For instance, most maintainers have expressed negative feelings toward integrating new ports using cc0, or with define_peephole, or with ASM prologues/epilogues. I have proposed a patch in the past to document this and it has been rejected on the basis that there is no official statement on this. I think that the SC should take a position on how to resolve this issue (see below for my suggestion), otherwise we are going to really annoy people. - At this point, there are at least three pending new ports, one of which have not been reviewed for 9 months already. The only comments they have received are the usual generic comments like "document every function and arguments", or "you need a copyright assignments and you should volunteer to maintain this". Once these nitpicks are done, the patch goes unreviewed forever. I believe we are losing valuable contributions with this behaviour. The only new port that went in is Blackfin, because it was contributed by a GWP which was allowed to commit it without waiting for the review. - I read several times messages by users which believe that GCC is changing trend, going towards supporting only a handful of very common systems, instead of being a generic compiler open to every small platform the open source community needs to support. I do not believe this is the official mission statement of GCC, but the fact that some users *start* to believe this should make the SC think that maybe we need to be more open towards new ports. I'm kindly asking the SC: 1) An official statement about whether GCC is going to still accept every new port which is technically fit and actively maintained, or is now going to restrict the number of targets to the few most important systems for maintenance reasons. 2) An official up-to-date list of technical requirements for a new port to be accepted. 3) Some sort of formal procedure which gives some basic guarantees that new ports are going to be reviewed and eventually accepted. For instance, one solution could be auto-approval for new ports which follow the new technical list and with active maintainers, if the patch went unreviewed for some months. I think it could be a good idea to appoint a new maintainer in charge for new ports, at least to do the leg-work (checklist validation of the port) and to provide some official feedback to the contributors. Thanks. -- Giovanni Bajo
Re: more on duplicate decls
Kenneth Zadeck <[EMAIL PROTECTED]> wrote: > Are you saying that if I wait til the front end is finished that I do > not have to worry about the default args problem you mention above? Yes. The middle-end does not know anything about default arguments: they are used only internally by the C++ frontend. When the trees enter the middle-end, the FUNCTION_DECLs do not need the default arguments, the CALL_EXPR are filled correctly, and the programmer errors have been already reported. > Should I fix it this simple way or should I let a c++ front end person > fix it as the decls are created? I believe the simple way is faster for you to continue with you work. The proper fix does not look easy at all. -- Giovanni Bajo
Re: MEMBER_TYPE and CV qualifiers
Mark Mitchell <[EMAIL PROTECTED]> wrote: > The function type is no more > cv-qualified than any other function type; the only thing that's > cv-qualified is the type pointed to by the first argument. The standard does not agree with you though, see 9.3.1/3. In fact, what happens is that we currently deduce the type wrong (PR 8271) because of the fact that the METHOD_TYPE is not cv-qualified. So either we special-case this, or we represent it correctly. FWIW, Jason agreed that the right way to fix this problem is to put cv qualification on METHOD_TYPE, rather than special-case hacks: http://gcc.gnu.org/ml/gcc-patches/2004-07/msg00550.html http://gcc.gnu.org/ml/gcc-patches/2004-07/msg00630.html -- Giovanni Bajo
Re: Problems on Fedora Core 4
Michael Gatford <[EMAIL PROTECTED]> wrote: > std::map::const_iterator functionIterator = > quickfindtag.find(funcname); It's missing a typename keyword here: typename std::map::const_iterator functionIterator = See: http://gcc.gnu.org/gcc-3.4/changes.html, C++ section. -- Giovanni Bajo
Re: extension to -fdump-tree-*-raw
Ebke, Hans-Christian <[EMAIL PROTECTED]> wrote: > So to resolve that problem I took the gcc 4.0.1 source code and patched > tree.h and tree-dump.c. The patched version introduces two new options for > -fdump-tree: The "parseable" option which produces unambiguous and easier to > parse but otherwise similar output to "raw" and the "maskstringcst" option > which produces output with the string constants masked since this makes > parsing the output even easier and I'm not interested in the string > constants. You could write some code to escape special characters, so to write something like: @54 string_cst type: @61 strg: "wrong type:\n\0\0\xaf\x03\x03foo\"bar" lngt: 19 This would not need a different special option. -- Giovanni Bajo
Re: extension to -fdump-tree-*-raw
Ebke, Hans-Christian <[EMAIL PROTECTED]> wrote: > I have to write this in Outlook, so I don't even try to get the quoting > right. Sorry. :-( http://jump.to/outlook-quotefix > But it would break applications relying on the old format. There is no format either. dump-tree is *very* specific of GCC inners, and it can dramatically changes between releases. OK, maybe not the syntax, but the semantic. I wouldn't care of the syntax at that point. -- Giovanni Bajo
Re: gcc 3.3.6 - stack corruption questions
Louis LeBlanc <[EMAIL PROTECTED]> wrote: > The problem is I'm getting core dumps (SEGV) that appears to come from > this code when I know it shouldn't be in the execution path. The code > in question is switched on by a command line argument only, and the > process is managed by a parent process that monitors and manages it's > execution - reporting crashes and restarting it if necessary. Looks like a bug hidden in your code. Several things you could try: - valgrind - GCC 4.0 with -fmudflap - GCC 4.1 CVS with -fstack-protect -- Giovanni Bajo
Re: gcc 3.3.6 - stack corruption questions
Louis LeBlanc <[EMAIL PROTECTED]> wrote: > I added the -fstack-check switch to my makefile and recompiled with > various optimizations. I was pretty surprised at the file sizes that > showed up: > > No Optimization: > -rwxr-xr-x 1 leblanc daemon 1128660 Jul 25 16:25 myprocess* > > Optimized with -O2 > -rwxr-xr-x 1 leblanc daemon 1058228 Jul 25 17:36 myprocess* > > Optimized with -O3 > -rwxr-xr-x 1 leblanc daemon 1129792 Jul 25 17:32 myprocess* > > I would have expected much different results. Shouldn't the file > sizes be smaller (at least a little) with the -O3 switch? Maybe > there's a loop unrolled to make it faster, resulting in a larger > codebase? Or inlining, or many other things. If you care about size, use -Os. -- Giovanni Bajo
Wrong ChangeLog entries
Mark, - with your commit for PR 20142, you also committed a hunk to name-lookup.c which is not described in the ChangeLog. It is also unclear whether it is effectively need for that PR or not, but nonetheless it went in, so the entry should probably be fixed. - It is unclear which patch fixed PR 19063, which patch fixed PR 13268, or if the same patch fixed both. * Both bugs were closed at the same time, but the ChangeLog entry does not mention PR 19063. (To add confusion, the original ChangeLog entry mentioned a totally unrelated bug (17413) instead of PR13268, but that typo was later fixed in CVS). * In the testsuite, I cannot find a testcase for PR13268, I can only find a testcase for PR 19063 (g++.dg/template/crash31.C), and the testcase is also wrong (contains a typo, so it does not probably test what it was supposed to test). * The patch in the mail in gcc-patches (http://gcc.gnu.org/ml/gcc-atches/2004-12/msg01697.html) adds even more confusion because it contains the diff for crash31.C but with a different heading comment (PR c++/13268 instead of PR c++/19063). If those bugs were duplicates, it should have probably be mentioned in both the ChangeLog and the bug description; also one should be closed as duplicate of the other, instead of simply marked as "fixed". Giovanni Bajo
Re: Large, modular C++ application performance ...
michael meeks <[EMAIL PROTECTED]> wrote: > I've been doing a little thinking about how to improve OO.o startup > performance recently; and - well, relocation processing happens to be > the single, biggest thing that most tools flag. > > Anyhow - so I wrote up the problem, and a couple of potential > solutions / extensions / workarounds, and - being of a generally > clueless nature, was hoping to solicit instruction from those of a more > enlightened disposition. > > All input much appreciated; no doubt my terminology is irritatingly up > the creek, hopefully the sentiment will win through. > > http://go-oo.org/~michael/OOoStartup.pdf > > Two solutions are proposed - there are almost certainly more that I'm > not thinking of. I'm interested in people's views as to which approach > is best. So far the constructor hook approach seems to be the path of > least resistance. I'm slow, but I can't understand why a careful design of the interfaces of the dynamic libraries, together with the new -fvisibility flags, should not be sufficient. It worked well in other scenarios (http://gcc.gnu.org/wiki/Visibility). IMHO, it's unreasonable to break the C++ ABI for 1 second of warm time startup. -- Giovanni Bajo
Re: [GCC 4.2 Project] Replacements for CSE path following
Paolo Bonzini <[EMAIL PROTECTED]> wrote: > This pass does simple forward propagation and simplification when > an operand of an insn can only come from a single def. The pass has a > very good potential of catching simplifications currently done by > inter-basic-block CSE (-fcse-follow-jumps and -fcse-skip-blocks) and > combine: however, it is much faster than inter-basic-block CSE and > runs much earlier than combine. It is not clear whether this patch will make -fcse-follow-jumps / -fcse-skip-blocks obsolete and thus disable/remove them. I think this should be clearly stated. Giovanni Bajo
