RE: Best way to compute cost of a sequence of gimple stmt

2014-06-10 Thread Thomas Preud'homme
> From: Richard Biener [mailto:richard.guent...@gmail.com] > Sent: Tuesday, June 10, 2014 5:16 PM > > In general this is impossible to do. I don't have a good answer on > how to determine whether (unaligned) load + bswap is faster than > doing sth else - but there is a very good chance that the

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Richard Biener
On June 10, 2014 8:04:13 PM CEST, Steven Noonan wrote: >On Tue, Jun 10, 2014 at 10:46 AM, Linus Torvalds > wrote: >> On Tue, Jun 10, 2014 at 6:23 AM, Jiri Kosina wrote: >>> We have been chasing a memory corruption bug, which turned out to be >>> caused by very old gcc (4.3.4), which happily turne

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Jiri Kosina
On Tue, 10 Jun 2014, Linus Torvalds wrote: > > We have been chasing a memory corruption bug, which turned out to be > > caused by very old gcc (4.3.4), which happily turned conditional load into > > a non-conditional one, and that broke correctness (the condition was met > > only if lock was held)

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Steven Noonan
On Tue, Jun 10, 2014 at 10:46 AM, Linus Torvalds wrote: > On Tue, Jun 10, 2014 at 6:23 AM, Jiri Kosina wrote: >> We have been chasing a memory corruption bug, which turned out to be >> caused by very old gcc (4.3.4), which happily turned conditional load into >> a non-conditional one, and that br

Re: Issue with sub-object __builtin_object_size

2014-06-10 Thread Jakub Jelinek
On Tue, Jun 10, 2014 at 07:37:50PM +0200, Ulrich Weigand wrote: > the following C++ test case: > > struct pollfd > { > int fd; > short int events; > short int revents; > }; > > struct Pollfd : public pollfd { }; > > struct Pollfd myfd[10]; > > int test (void) > { > return __bu

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Linus Torvalds
On Tue, Jun 10, 2014 at 6:23 AM, Jiri Kosina wrote: > We have been chasing a memory corruption bug, which turned out to be > caused by very old gcc (4.3.4), which happily turned conditional load into > a non-conditional one, and that broke correctness (the condition was met > only if lock was held

Issue with sub-object __builtin_object_size

2014-06-10 Thread Ulrich Weigand
Hello, the following C++ test case: struct pollfd { int fd; short int events; short int revents; }; struct Pollfd : public pollfd { }; struct Pollfd myfd[10]; int test (void) { return __builtin_object_size ((struct pollfd *)myfd, 1); } ends up returning 8 from the "test" rou

RE: broken links?

2014-06-10 Thread Hebenstreit, Michael
you are right - must be a Firefox problem; I had no problem using wget, IE8 works as well Firefox is still redirected to https://gcc.gnu.org/pub/gcc/infrastructure/ though sorry for alarm thanks for reply Michael -Original Message- From: Jonathan Wakely [mailto:jwakely@gmail.com]

Re: broken links?

2014-06-10 Thread Jonathan Wakely
On 10 June 2014 17:41, Jonathan Wakely wrote: > On 10 June 2014 17:20, Hebenstreit, Michael wrote: >> Either something is broken on my web-access or the links on >> https://gcc.gnu.org/install/prerequisites.html pointing to >> ftp://gcc.gnu.org/pub/gcc/infrastructure/ are gone - can't find the fi

Re: broken links?

2014-06-10 Thread Jonathan Wakely
On 10 June 2014 17:20, Hebenstreit, Michael wrote: > Either something is broken on my web-access or the links on > https://gcc.gnu.org/install/prerequisites.html pointing to > ftp://gcc.gnu.org/pub/gcc/infrastructure/ are gone - can't find the files > anywhere else :( The FTP site and files are

broken links?

2014-06-10 Thread Hebenstreit, Michael
Either something is broken on my web-access or the links on https://gcc.gnu.org/install/prerequisites.html pointing to ftp://gcc.gnu.org/pub/gcc/infrastructure/ are gone - can't find the files anywhere else :( Thanks for all your efforts Michael

Re: Weird startup issue with -fsplit-stack

2014-06-10 Thread Ian Lance Taylor
On Tue, Jun 10, 2014 at 7:54 AM, Dmitry Antipov wrote: > On 05/21/2014 06:10 PM, Ian Lance Taylor wrote: > >> I'm sorry, I have nothing useful to suggest. I agree that that sounds >> like a stack overflow, which should in general be impossible with >> -fsplit-stack when using the gold linker. I

Re: How can I get started as a GCC developer

2014-06-10 Thread Jonathan Wakely
On 10 June 2014 16:38, Jonathan Wakely wrote: > On 10 June 2014 15:00, Basile Starynkevitch wrote: >> Once all is done and signed (both by FSF and you or your employer), add your >> real name in MAINTAINERS file. > > That's not needed until you get write access to the repository, but > you can sub

Re: How can I get started as a GCC developer

2014-06-10 Thread Jonathan Wakely
On 10 June 2014 15:00, Basile Starynkevitch wrote: > Once all is done and signed (both by FSF and you or your employer), add your > real name in MAINTAINERS file. That's not needed until you get write access to the repository, but you can submit patches and contribute without write access.

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Jakub Jelinek
On Tue, Jun 10, 2014 at 05:13:29PM +0200, Peter Zijlstra wrote: > On Tue, Jun 10, 2014 at 05:04:55PM +0200, Marek Polacek wrote: > > On Tue, Jun 10, 2014 at 04:53:27PM +0200, Peter Zijlstra wrote: > > > On Tue, Jun 10, 2014 at 03:23:36PM +0200, Jiri Kosina wrote: > > > > +# Tell gcc to never replac

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Peter Zijlstra
On Tue, Jun 10, 2014 at 05:04:55PM +0200, Marek Polacek wrote: > On Tue, Jun 10, 2014 at 04:53:27PM +0200, Peter Zijlstra wrote: > > On Tue, Jun 10, 2014 at 03:23:36PM +0200, Jiri Kosina wrote: > > > +# Tell gcc to never replace conditional load with a non-conditional one > > > +KBUILD_CFLAGS+=

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Marek Polacek
On Tue, Jun 10, 2014 at 04:53:27PM +0200, Peter Zijlstra wrote: > On Tue, Jun 10, 2014 at 03:23:36PM +0200, Jiri Kosina wrote: > > +# Tell gcc to never replace conditional load with a non-conditional one > > +KBUILD_CFLAGS += $(call cc-option,--param allow-store-data-races=0) > > + > > Why do

Re: Weird startup issue with -fsplit-stack

2014-06-10 Thread Dmitry Antipov
On 05/21/2014 06:10 PM, Ian Lance Taylor wrote: I'm sorry, I have nothing useful to suggest. I agree that that sounds like a stack overflow, which should in general be impossible with -fsplit-stack when using the gold linker. I don't know what is happening here. I've tested with massive recur

Re: [PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Peter Zijlstra
On Tue, Jun 10, 2014 at 03:23:36PM +0200, Jiri Kosina wrote: > +# Tell gcc to never replace conditional load with a non-conditional one > +KBUILD_CFLAGS+= $(call cc-option,--param allow-store-data-races=0) > + Why do we not want: -fmemory-model=safe? And should we not at the very least als

Re: How can I get started as a GCC developer

2014-06-10 Thread Basile Starynkevitch
On Tue, Jun 10, 2014 at 06:30:54PM +0800, Anonymous User wrote: I'm not sure that being anonymous is helpful on GCC (and it might even be frowned upon, but I don't want to start a flamewar) I think that you need and you want to be identified. Besides, working on GCC is difficult; you'll soon be

Re: How can I get started as a GCC developer

2014-06-10 Thread Ian Lance Taylor
On Tue, Jun 10, 2014 at 3:30 AM, Anonymous User wrote: > > I'd like to help with the modularization of GCC. > > I've visited the getting started page at the official wiki but its contents > seem too old. I'm fairly new to GCC and and I'm bewildered by its huge code > base with lengthy and complica

[PATCH] tell gcc optimizer to never introduce new data races

2014-06-10 Thread Jiri Kosina
We have been chasing a memory corruption bug, which turned out to be caused by very old gcc (4.3.4), which happily turned conditional load into a non-conditional one, and that broke correctness (the condition was met only if lock was held) and corrupted memory. This particular problem with that

Re: [GSoC] decision tree first steps

2014-06-10 Thread Richard Biener
On Tue, Jun 10, 2014 at 1:06 PM, Prathamesh Kulkarni wrote: > On Fri, Jun 6, 2014 at 7:18 PM, Richard Biener > wrote: >> On Fri, Jun 6, 2014 at 12:02 PM, Richard Biener >> wrote: >>> On Fri, Jun 6, 2014 at 11:02 AM, Prathamesh Kulkarni >>> wrote: On Mon, Jun 2, 2014 at 6:14 PM, Richard Bie

implicit gnat_malloc seen as vararg function

2014-06-10 Thread BELBACHIR Selim
Hi, I'm working on a private port of GCC 4.7.3/GNAT 7.1.2. Calls to ADA 'new' operator generates implicit gnat_malloc(size) calls (which has to be provided by user program or runtime). In my macro INIT_CUMULATIVE_ARGS I noticed that gnat_malloc(size) calls are seen as vararg function because t

How can I get started as a GCC developer

2014-06-10 Thread Anonymous User
Hello everyone, I'd like to help with the modularization of GCC. I've visited the getting started page at the official wiki but its contents seem too old. I'm fairly new to GCC and and I'm bewildered by its huge code base with lengthy and complicated makefiles and sophisticated internal mecha

Re: Best way to compute cost of a sequence of gimple stmt

2014-06-10 Thread Richard Biener
On Tue, Jun 10, 2014 at 10:32 AM, Thomas Preud'homme wrote: > Hi there, > > With recent changes to it, the bswap pass can now replace a series of > (probably aligned) load + bitwise operation (AND, OR and shifts) + casts > by a (potentially unaligned) load and a bswap. I was rightfully pointed > o

Best way to compute cost of a sequence of gimple stmt

2014-06-10 Thread Thomas Preud'homme
Hi there, With recent changes to it, the bswap pass can now replace a series of (probably aligned) load + bitwise operation (AND, OR and shifts) + casts by a (potentially unaligned) load and a bswap. I was rightfully pointed out that this might be more expensive than the original sequence of gimpl