pengfei added a comment. In D99675#2695424 <https://reviews.llvm.org/D99675#2695424>, @kpn wrote:
> What changes are needed for a backend, and what happens if they aren't done? As far as I understand it, backend does optimizations based on patterns of the known nodes and MIs. Inserting a new node/MI will block any optimizations across the fence. So it respects the semantics of the intrinsic without target special chenges. I'm not sure if there's room for optimization cross the `arithmetic.fence`. If there is and no changes for it, backend may have some performance loss under these circumstances. > Having something needed for correctness silently not work seems ... > sub-optimal. I think backend is conservative for optimizations when use the intrinsic. It won't have correctness issue silently, but performance loss might. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D99675/new/ https://reviews.llvm.org/D99675 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
