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?
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.
