Work around crashes and incorrect results in scan-based algorithms when compiling with -O0

[mmichel11]

On certain integrated graphics architectures, sub-group sizes of 32 are not supported for kernels with certain properties when compiled with -O0 using the icpx compiler. The compiler is normally able to workaround this issue by compiling to a sub-group size of 16 instead. However, in cases in which an explicit sub-group size is required, then the compiler throws an exception at JIT time. This issue directly affects our reduce-then-scan implementation which has a required sub-group size of 32.

To properly work around this issue, several things must be done. Firstly, exception handling is implemented to catch this synchronous exception while re-throwing any other exceptions back to the user. Secondly, after discussion with compiler developers, kernel compilation must be separated from execution of the kernel to prevent corruption of the underlying sycl::queue that occurs when this exception is thrown after implicit buffer accessor dependencies around the kernel have been established. To do this, kernel bundles are used to first compile the kernel before executing.

[SergeyKopienko]

I never seen before in our code the examples of usage std::optional.
From my point of view we may simple write try / catch instead of __handle_sync_sycl_exception and don't use std::optional at all.

[mmichel11]

I never seen before in our code the examples of usage std::optional'. From my point of view we may simple write try / catchinstead of__handle_sync_sycl_exceptionand don't usestd::optional' at all.

I don't have a strong preference if we choose to go with the way I implemented or just directly add try ... catch throughout this header. I initially did this to avoiding having many try catch statements here.

Let me leave this open first for others' opinions to see if they prefer a more functional approach or just directly adding try...catch throughout.