On Mon, Oct 28, 2019 at 10:47 PM Jakub Jelinek <ja...@redhat.com> wrote: > > On Mon, Oct 28, 2019 at 03:41:13PM -0600, Jeff Law wrote: > > On 10/28/19 2:27 PM, Segher Boessenkool wrote: > > > On Mon, Oct 28, 2019 at 01:40:03PM -0600, Jeff Law wrote: > > >> On 10/25/19 6:01 PM, Gabriel Dos Reis wrote: > > >>> Jason, Jonathan - is the situation on the terrain really that dire that > > >>> C++11 (or C++14) isn't at all available for platforms that GCC is > > >>> bootstrapped from? > > >> The argument that I'd make is that's relatively uncommon (I know, I know > > >> AIX) that bootstrapping in those environments may well require first > > >> building something like gcc-9. > > >> > > >> I'd really like to see us move to C++11 or beyond. Sadly, I don't think > > >> we have any good mechanism for making this kind of technical decision > > >> when there isn't consensus. > > > > > > Which GCC version will be required to work as bootstrap compiler? Will > > > 4.8.5 be enough? > > I'd say gcc-9. What would we gain by making it 4.8 or anything else > > that old? > > That is not a good idea, it will make it much harder to build gcc because > not everybody has gcc-9 built as a system compiler. > The previous minimum requirement of 4.1 is perhaps too old now that 4.8 is > something we could require and gain through that C++11 support, but we > shouldn't follow Rust with "you can only build it with 6 weeks old previous > release and nothing else". > As discussed earlier, we gain most through C++11 support, there is no need > to jump to C++17 or C++20 as requirement.
Yes, I've agreed to raise the requirement to GCC 4.8 which provides C++11 support. For convenience we could also provide a configure-time hint if the host compiler doesn't have C++11 support or is older than 4.8.2 (I think .1 has some issues). Rather than only running into some obscure errors later on. Richard. > Jakub >
