Anastasia added a comment. In D69938#1755709 <https://reviews.llvm.org/D69938#1755709>, @rjmccall wrote:
> In D69938#1754894 <https://reviews.llvm.org/D69938#1754894>, @Anastasia wrote: > > > In D69938#1752024 <https://reviews.llvm.org/D69938#1752024>, @rjmccall > > wrote: > > > > > Yes, in that case copy-elision into the global variable is guaranteed. > > > You can write arbitrary expressions in global initializers, however, and > > > those can use temporary lambdas. > > > > > > I guess you mean something like this? > > > > auto glambda = []() { return 1; }(); > > > > > Yes, or just passing it as an argument to something. > > > I don't see a way to change the address space of a lambda object however. > > It would only be possible to specify addr space qualifiers for a call > > operator of such lambdas. > > Yes, I think the language has to say what address space the lambda temporary > is in. Among other things, this can affect how captures are initialized, > since some constructors are only usable in certain address spaces. (Lambdas > in global contexts can't capture surrounding local variables, but they can > still have explicitly-initialized captures, like `[x=foo()] { ... }`.) That > language rule could be that lambda temporaries are always in the private > address space, or it could be that lambdas in global contexts are in the > global address space. The latter might be easier because it's compatible > with lifetime-extension: we don't necessarily know when processing the lambda > whether its temporary will be lifetime-extended, and if it is, it needs to be > in the global address space. The only disadvantage of that is that we'd have > to use global memory even for non-extended temporaries in global initializers. > > Richard might have thoughts about this. I don't know if there's been any > language work around copy-elision and/or lifetime-extension that might be > stretchable to allow us to delay the address-space decision until later. Ok, I see. Thanks! I agree for OpenCL `__global` might make more sense for the program scope lambdas. I will look into this. However, would it be ok to proceed with this patch adding `__generic` address space as a qualifier to lambda call operators by default. Is there anything that should be added to complete it? CHANGES SINCE LAST ACTION https://reviews.llvm.org/D69938/new/ https://reviews.llvm.org/D69938 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
