[SYCL][SUBGROUPS] Non-integral types incompatible with sg.load()

[jasonsewall-intel]

Issue:
subgroup.load fails for non-integral types like float and double. Using bit_cast seems to fail too.

Expected behavior:

load shouldn't care about the data type, just the width.

auto vals = ;// read-capable access to buffer of doubles
const int o = ;// some positive integer
const double v = sg.load<1>(vals.get_pointer()+o);

Details:

I would expect bit_cast to work here, but it does not:

const double v = detail::sub_group::bit_cast<const double>(sgr.load<1>(detail::sub_group::bit_cast<multi_ptr<unsigned long, access::address_space::global_space>>(vals.get_pointer()+o)));

[Pennycook]

fe8d852 just added support for 64-bit sub-group loads/stores. I'm still looking into what we should do for user-defined types, but float and double should work now.

[AlexeySachkov]

The most up-to-date spec on sub_group::load<T>() says that T must be a NumericType and it looks like our implementation supports it since #1031.

At least I'm able to compile the following snippet just fine:

SYCL_EXTERNAL void foo(nd_item<1> it, bar *ptr) {
  auto sg = it.get_sub_group();
  auto val = sg.load<bar>(ptr);
}

I will close this one assuming that it is fixed, but we should probably extend our test to get this case covered