On Fri, 20 Mar 2026 at 17:48, Claudio Bantaloukas <[email protected]> wrote: > > On 20/03/2026 17:27, Jonathan Wakely wrote: > > On Fri, 20 Mar 2026 at 15:58, Christophe Lyon via Gcc <[email protected]> > > wrote: > >> > >> > >> > >> On 3/20/26 11:15, Jakub Jelinek via Gcc wrote: > >>> On Fri, Mar 20, 2026 at 09:47:08AM +0000, Claudio Bantaloukas via Gcc > >>> wrote: > >>>> Title says it all really. > >>>> > >>>> Why am I asking? I'd like to try writing a build that checks stage1 works > >>>> with the earliest version of gcc the project wants to support. > >>>> > >>>> https://gcc.gnu.org/install/prerequisites.html currently says: > >>>> - GCC 5.4 or newer has sufficient support for used C++14 features. > >>>> - If you need to build an intermediate version of GCC in order to > >>>> bootstrap > >>>> current GCC, consider GCC 9.5 > >>>> > >>>> Should it use gcc 5.4? Is it time to increase that version? > >>> > >>> Yes. No. > >>> > >>> We don't increase the minimum requirement just for fun, but when it gives > >>> significant benefits for the codebase and the earliest supported gcc is > >>> still old enough (unlike especially rustc but also LLVM we try not to > >>> require too recent stuff for building). > >>> The reason to go to gcc 5.4 [1] (which already causes significant pain, > >>> several > >>> CompilerFarm machines still have system gcc 4.8.5) was to be able to use > >>> C++14 and so not be as limited in constexpr functions as in C++11. > >> > >> I believe Claudio is aiming at adding such builds in the forge CI (happy > >> to help btw ;-) ), so I suppose a follow-up question is what distro & > >> version should a container use? Claudio shared a list in his message, > >> none of which matches the exact 5.4 requirement. > >> > >> Does this mean starting with an ubuntu-16.04 (ships gcc-5.3.1) and > >> build/install gcc-5.4.0 in it, and use the resulting image? > > Cristophe, you're right, I've been wanting to add such a check for a > while. But I'd like to add a twist to it. Rather than use an unsupported > operating system, requiring vsyscall emulation, I'd rather try and build > an older version of gcc on top of a new distribution. > > > Well based on what Jakub said, the Ubuntu 5.3.1 might be OK to build trunk. > > > > Until a few weeks ago, I was building every trunk snapshot using the > > Ubuntu 16:04 system compiler. I switched to 18:04 because something > > was failing, but I don't know if it was a temporary breakage on trunk. > > I guess we'll find out at some point :)
The gcc-16-20260315 snapshot builds fine on Ubuntu 16:04, I just tried it.
