On 11/22/19 4:41 PM, Segher Boessenkool wrote: > On Fri, Nov 22, 2019 at 11:36:18PM +0100, Jakub Jelinek wrote: >> On Fri, Nov 22, 2019 at 04:01:43PM -0600, Segher Boessenkool wrote: >>> On Fri, Nov 22, 2019 at 09:02:05PM +0000, Andrew Dean wrote: >>>>>> Many systems do not have a system compiler newer than this *four years >>>>>> old* one. GCC 4.8 is the first GCC version that supports all of >>>>>> C++11, which is the only reason it would be even near acceptable to >>>>>> require something this *new*. >>>>> >>>>> Agreed. Note we're even shipping new service packs for SLE12 which has >>>>> that >>>>> "ancient" compiler version (OTOH there _is_ a fully supported GCC 9 >>>>> available >>>>> for SLE12 as well). >>>>> >>>>> So, if we want C++11 then fine. But requiring GCC 9+ isn't going to fly. >>>>> IIRC >>>>> GCC 6 is first having -std=c++14 by default, but unless there's a >>>>> compelling >>>>> reason to use C++14 in GCC I'd rather not do it at this point. >>>>> >>>>> Removing all the workarounds in the tree we have for GCC 4.[12].x would of >>>>> course be nice. >>>>> >>>>> But I have to update the testers that still use GCC 4.1.x as host >>>>> compiler :P >>> >>>> Richard/Segher: Are we in agreement that we can move forward with updating >>>> to c++11 as the minimum version? I have made the simple change locally to >>>> modify the flag and verified that I got the exact same test results >>>> with/without the change. I can look into the work to add a configuration >>>> warning if the compiler doesn't support c++11, but wanted to make sure we >>>> are on the same page before doing so. >>> >>> If GCC 4.8.5 works as bootstrap compiler, it is fine with me, and good >>> progress too. (Which means 4.8.5 has to work for at least all primary >>> targets.) >> >> What would be the advantage of bumping the requirement now as opposed to at >> the start of next stage 1 though? We should be fixing bugs now, not >> introduce new features nor do code refactoring. > > Oh, I meant for GCC 11, of course. I thought we all agreed on that. Yea, I don't see that stepping forward for gcc-10 really brings us anything. We're past stage1 and thus Andrew's work would naturally target gcc-11.
So the advice I'd give Andrew is go ahead with using C++11 as needed. However, also try to be sensible in terms of what features you use :-) jeff
