This > On 30 Aug 2023, at 00:32, Ben Boeckel via Gcc <gcc@gcc.gnu.org> wrote: > > On Tue, Aug 29, 2023 at 18:57:37 +0200, Richard Biener wrote: >> I suppose for bootstrapping we could disable ISL during stage1 since >> it enables an optional feature only. Other than that GCC only >> requires a C++11 compiler for building, so ISL breaks that constraint >> with requiring C++17. > > Note that it doesn't *require* it per sé; the tests that try it are > compiled if C++17 support was detected at all. The headers seem to just > have optional header-only `std::any`-using APIs if C++17 is around. > `isl` supporting a flag to disable the tests would also work, but that > doesn't fix 0.26. It also doesn't mean it won't start requiring C++17 at > some point in the future.
Perhaps, in the short-term (i.e. before it requires C++ > 11) we can solve this by ensuring that we pass -std=c++11 to the configure stages as well as to the build. ISTM that configure is finding C++17-capability (because we do not, I think, force C++11 for the configure) and then the build takes it away by forcing -std=c++11. [ will try this out ] > In light of that, I feel that skipping it for bootstrap is probably the > right solution here. Alas, my skill with autotools is closer to the > caveman-with-club level rather than that of a surgeon. I am not sure we have an easy way to exclude a host module from stage1 only (but ICBW). Iain > > --Ben
