Anastasia added a comment. In D68388#1756701 <https://reviews.llvm.org/D68388#1756701>, @kpet wrote:
> Thanks for the feedback. > > > I think we should use -fpermissive rather than adding similar flag to Clang. > > Could you point me at a use of `-fpermissive` for a similar case? Also it > seems `-fpermissive` is not mentioned in the Clang manual or the help text. > Am I missing something? bin/clang -fpermissive test.cl Clang already has the flag added. So you can just start using it I presume. Feel free to document it. > > >> At the end we might end up with other cases where we need similar mechanism >> it doesn't make sense to add a flag for each case. > > Completely agree and that was one of the reasons I decided to add a generic > flag like this. I felt that compatibility with existing OpenCL C source was > an important enough use-case to warrant adding a flag for it especially > since, as you say, we expect such a flag could be useful to control several > bits of behaviour. > >> Also I am not sure that what you are doing here is really enabling OpenCL C >> compatibility mode that would imply to me that restrict is expected to >> behave in C++ mode as it was in C but is it really the case? > > Isn't restrict mainly an optimisation feature? That's certainly my reading of > 6.7.3-7 in the C99 spec: > >> The intended use of the restrict qualifier (like the register storage class) >> is to promote >> optimization, and deleting all instances of the qualifier from all >> preprocessing translation >> units composing a conforming program does not change its meaning (i.e., >> observable >> behavior). > > The main goal here is to be able to consume existing OpenCL C source without > modifications. I thought that enabling existing behaviour for > `restrict`/`__restrict` that may result in additional optimisations was more > useful than just discarding `restrict`, which would be a valid way of > achieving compatibility. Is there something specific that worries you? C++ deviates from C so restrict in C++ might not be restrict in C. Can we confidently say we will support restrict exactly like OpenCL C does i.e. C99? In other words I believe it is much safe to say that we support `restrict` in adhoc way that deviates C++ for OpenCL documentation without implying developers should refer to OpenCL C and C99 spec to get how it works. We can also use this mechanism for any behavior that deviates the documentation rather than adding a flag for each (i.e. we might want to deviate in something that doesn't come from OpenCL C at all). Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D68388/new/ https://reviews.llvm.org/D68388 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
