Anastasia added a comment. In https://reviews.llvm.org/D25343#567374, @tstellarAMD wrote:
> In https://reviews.llvm.org/D25343#565288, @Anastasia wrote: > > > Do you have any code example where Clang/LLVM performs wrong optimizations > > with respect to the control flow of SPMD execution? > > > > My understanding from the earlier discussion we have had: > > https://www.mail-archive.com/cfe-commits@lists.llvm.org/msg22643.html that > > noduplicate is essentially enough for the frontend to prevent erroneous > > optimizations. Because in general compiler can't do much with unknown > > function calls. > > > noduplicate is enough for correctness, but it prevents legal optimizations, > like unrolling loops with barriers. The convergent attribute was added > specifically for these kinds of builtins, so we should be using it here > instead of noduplicate. Should we deprecate noduplicate then as convergent should cover both use cases for OpenCL I believe? As far as I understand noduplicate was added specifically for SPMD use cases... ================ Comment at: include/clang/Basic/AttrDocs.td:630 + void convfunc(void) __attribute__((convergent)); + // Setting it as a C++11 attribute is also valid in a C++ program. + // void convfunc(void) [[clang::convergent]]; ---------------- Did you mean "in an OpenCL program"? ================ Comment at: test/CodeGenOpenCL/convergent.cl:17 +// } else { +// non_conffun(); +// } ---------------- -> non_convfun(); https://reviews.llvm.org/D25343 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
