[SYCL] Cannot use placeholder accessors with property lists.

[j-stephan]

The accessor properties extensions introduces an additional template parameter for accessors:

namespace sycl {
template <typename dataT,
          int dimensions,
          access::mode accessmode,
          access::target accessTarget,
          access::placeholder isPlaceholder,
          typename property_listT = accessor_property_list<>> // here
class accessor {

However, this cannot be used together with placeholder accessors because handler::require is missing this parameter:

llvm/sycl/include/CL/sycl/handler.hpp

Line 1079 in 5860468

require(accessor<DataT, Dims, AccMode, AccTarget, access::placeholder::true_t>

Example error from my test cases:

/home/jan/sycl-workspace/sycl/build/bin/../include/sycl/CL/sycl/handler.hpp:896:3: note: candidate template ignored: could not match 'accessor_property_list<(no argument)>' against 'accessor_property_list<sycl::INTEL::property::buffer_location::instance<0>>'
  require(accessor<DataT, Dims, AccMode, AccTarget, access::placeholder::true_t>
  ^

[j-stephan]

From a quick glance, this seems to affect the copy methods, too. Interestingly, fill would work because it supports the template parameter.

[github-actions]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be automatically closed in 30 days.

[AlexeySachkov]

Complete reproducer:

#include <sycl/sycl.hpp>

int main() {
  sycl::queue q;
  sycl::buffer<int> buffer(sycl::range{1});
  q.submit([&](sycl::handler &cgh) {
    sycl::accessor acc(
        buffer, cgh,
        sycl::ext::oneapi::accessor_property_list{sycl::ext::oneapi::no_alias});
    cgh.require(acc);

    cgh.parallel_for(1, [=](sycl::item<1> itemIdx) {
      const int v = itemIdx.get_linear_id();
      acc[v] = v;
    });
  });
  return 0;
}

The issue still exists. Also, we should probably update the spec to explicitly mention that handler::require signature must be updated if extension is supported. Tagging @GarveyJoe