ia64: GCC developers want to deprecate the ia64 port

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mike155 · Post by **mike155** » Sat Jun 15, 2019 7:24 pm

Richard Biener wrote:ia64 has no maintainer anymore so the following deprecates it with the goal of eliminating the port for GCC 11 if no maintainer steps up.

See: https://gcc.gnu.org/ml/gcc/2019-06/msg00125.html

eccerr0r · Post by **eccerr0r** » Sun Jun 16, 2019 1:06 am

Can't say the day wasn't coming... even if the architecture was kind of immune to the speculation security issues.
I suspect its instruction ordering backends is probably one of the most intricate that's not directly applicable to any other architecture. Did icc get deprecated too?

Post by **John R. Graham** » Wed Jun 19, 2019 1:47 pm

I had been meaning to build an Itanium workstation just as a platform to gain experience with a VLIW instruction set. Looks like my window of opportunity for that is closing (although parts are probably cheap right now).

- John

eccerr0r · Post by **eccerr0r** » Thu Jun 20, 2019 3:46 am

Probably isn't worth it at this point... I should update my ia64 box's Gentoo install one last time or something before it becomes completely obsolete...

Post by **sam_** » Sun Feb 20, 2022 4:36 am

It's necrobumping but I'd like to just give a quick update here (it's a quiet section, so..).

I posted a summary of the IA64 situation to the gentoo-dev mailing list last month. Help is needed but support has not yet been dropped from the toolchain, 3 years on.

eccerr0r · Post by **eccerr0r** » Wed Feb 23, 2022 10:12 pm

I'm kind of disappointed with my ia64 since I haven't had graphics support for a while, AMD 2D graphics broke way back when and haven't used it since... my ia64 box has been sleeping for a while now.

Question is what I can do with the box nowadays... (2U, Dual 1.3GHz Madison 4GB RAM, RAID1 72GB disk)

Website · Post by **Zucca** » Wed Feb 23, 2022 10:36 pm

Out of curiosity... does llvm have support for ia64 "output"? Could it solve some of the upcoming problems?

eccerr0r · Post by **eccerr0r** » Thu Feb 24, 2022 12:00 am

heard they dropped or was thinking about dropping ia64 too...

Website · Post by **Zucca** » Thu Feb 24, 2022 9:47 am

Well, I'm not a compiler developer, but shouldn't it be quite easy to maintain ia64 support as the architecture will not evolve anymore..?
I guess the rest of the toolchain has something to do with it.

Post by Hu » Thu Feb 24, 2022 1:32 pm

The problem is that while the architecture will not evolve further, the shared code used by multiple architectures will continue to change. Changes in the core code may require changes in the architecture-specific backends, to handle updated data structures, call ordering rules, etc. Since IA64 is abandoned at the hardware level, it is difficult and time-consuming for developers to verify that they did not break the ia64 backend when they update it as part of a change to core code. If they don't update it, there's a good chance they will render it impossible to compile. If they do update it, they may have code that compiles, but produces nonsensical results when used.

eccerr0r · Post by **eccerr0r** » Thu Feb 24, 2022 2:42 pm

Same goes for sparc, hppa, alpha, ppc, ...?

Post by Hu » Thu Feb 24, 2022 4:12 pm

Depending on how readily a developer can buy, rent, or borrow access to those, yes.

eccerr0r · Post by **eccerr0r** » Thu Feb 24, 2022 4:34 pm

Well, even if you can buy, rent, or borrow these...all these architectures likely will not evolve further either...

Hmm... maybe I should see if my ia64 box will run latest or not anymore including X11...

Post by Hu » Thu Feb 24, 2022 5:41 pm

Right, but if developers cannot get access to try code on those machines, then their only choices are to declare the architecture unsupported (and subject to break at any time with no notice) or to refrain from ever touching core code that requires a change in the architecture-specific code of an obsolete architecture. For architectures where they can test, either personally or by assuming that a regularly active community member will do so, they can have some confidence that a given release does not have a serious unknown regression.

eccerr0r · Post by **eccerr0r** » Thu Feb 24, 2022 7:47 pm

What version of gcc is being used to build ia64 at the moment... seems there are no stable versions of gcc at all currently?
I'm sort of resource constrained and have completely powered off my ia64 box (as in unplugged; I used to keep it up on LOM but not anymore as the LOM uses as much power as a laptop fully turned on) and wonder what could be done to do more ia64 arch testing on my machine...

I suspect that making sure cross compiling with my amd64 boxes would be part of the solution, but I haven't updated crossdev on my amd64 boxes since gcc-4.7.4 -- the version of gcc on my ia64 box. Which means I probably need to reinstall the box from a fresh stage3 of something more recent, trying to upgrade this box from its current state is probably not worth the effort...

Post by **sam_** » Sun Feb 27, 2022 6:00 am

Zucca wrote:Well, I'm not a compiler developer, but shouldn't it be quite easy to maintain ia64 support as the architecture will not evolve anymore..?
I guess the rest of the toolchain has something to do with it.

This is of course true (it's not evolving anymore) but a fair part of why IA64 died is that the toolchain support never matured to fully take advantage of the ISA's capabilities. It's also not simple and the bugs are often a bit weird. It's not very similar to other arches which means it often doesn't benefit from other drive-by fixes too.

So, it's true, and this logic maybe applies a bit more to other arches, but the problem is, IA64 isn't starting from a good, well-maintained state

eccerr0r wrote:Same goes for sparc, hppa, alpha, ppc, ...?

sparc is in an interesting situation because the kernel support seems like it could do with a bit more love, but we actually know there's a bunch of unimplemented cool stuff like better power management which Solaris (and possibly Oracle's Linuxes had?). It has somewhat of an hobbyist following but a lot of SPARC fans actually prefer to use Solaris. But the toolchain benefits, even if the kernel doesn't so much, from this use.
hppa is rather well-maintained, surprisingly, although does not have 64-bit userland yet (does have 64-bit kernel support though). Needs toolchain support for that but it's not dead at all. I recently got a C8000 and I've been genuinely surprised by how alive the community is and how progress is going. Don't count PARISC out!
alpha is quite quiet but it's been around longer. The main Gentoo developer interested in alpha (mattst88) is also the kernel maintainer. I think there's some multiprocessing bug in the kernel which makes using at least his alpha system a pain atm though (an unfortunate part about some of this is that such bugs often aren't $ARCH specific, but are just exposed there because of slower/odd hardware or quirks, so you can't easily narrow down by checking $ARCH specific changes).
ppc has a decent enthusiast following (ppc64 anyway, in the form of e.g. RCS) and I think it's pretty common to see people testing it out in the wild. It's easily the "most popular fringe arch".

eccerr0r wrote:What version of gcc is being used to build ia64 at the moment... seems there are no stable versions of gcc at all currently?
I'm sort of resource constrained and have completely powered off my ia64 box (as in unplugged; I used to keep it up on LOM but not anymore as the LOM uses as much power as a laptop fully turned on) and wonder what could be done to do more ia64 arch testing on my machine...

I suspect that making sure cross compiling with my amd64 boxes would be part of the solution, but I haven't updated crossdev on my amd64 boxes since gcc-4.7.4 -- the version of gcc on my ia64 box. Which means I probably need to reinstall the box from a fresh stage3 of something more recent, trying to upgrade this box from its current state is probably not worth the effort...

IA64 lost stable keywords in Gentoo due to lack of interest and the time it was consuming. Could always come back with sufficient interest. As far as I'm aware, GCC 11 works fine still.

Just to reiterate on what I said in the ML post, really, more help is really welcome with all of these in any sense, including bug reports, simply telling us you're using them, and package testing.

eccerr0r · Post by **eccerr0r** » Sun Feb 27, 2022 6:40 am

At one time my ia64 box was the sole machine I owned that had 4GB RAM, but now that has changed...
Was kind of dismayed that things were breaking on it little by little... first Firefox was dropped (probably due to SSE2 of course) and then X11 stopped working. I always could boot.

So is gcc-11 what's in the current stage3? Will need to crossdev it on my "bigger" boxes even if the ia64 box is physically biggest and heaviest, no way I can move it around without a hand truck (it's a brick 2U)...