jdoerfert added a comment. In D124158#3477649 <https://reviews.llvm.org/D124158#3477649>, @efriedma wrote:
> The issue you're describing sounds like it's specific to @__shfl_sync. In > general, in C++, you aren't allowed to read from an uninitialized variable; > see [basic.indet] in the standard. But if your testcase doesn't have > undefined behavior, CUDA language rules must somehow allow this particular > builtin function to take undef variables as input. (Is this documented > somewhere?) > > That isn't related to the "convergent" attribute; the transform you're > describing doesn't break convergence rules. I concur, especially on the last part. So far I have not seen why this is tied in any way to convergent. It might be a shfl oddity in which case the proper solution is to `freeze` all shuffle arguments in clang. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D124158/new/ https://reviews.llvm.org/D124158 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
