# Supported OpenCL features

All mandatory features for OpenCL 1.2 are supported on x86-64+Linux, see Pocl OpenCL conformance for details.

# Known unsupported OpenCL features

The known unsupported OpenCL (both 1.x and 2.x) features are listed here as encountered.

## Frontend/Clang

- OpenCL 1.x
  - OpenGL interoperability extension
  - SPIR extension (partially available, see below)
- OpenCL 2.0
  - generic address space (recognized by LLVM 3.8+ but incomplete)
  - pipes (WIP)
  - device-side enqueue
- cl_khr_f16: half precision support (with the exception of vload_half / vstore_half)

## Unimplemented host side functions

All 1.2 API call should be implemented. The list of unimplemented 2.0 calls can be seen as the NULLs in the ICD dispatch struct in https://github.com/pocl/pocl/blob/master/lib/CL/clGetPlatformIDs.c

## SPIR support

There is some experimental support available for SPIR, with LLVM 5 and newer. There is some even more experimental support available for loading SPIR-V binaries, but this depends on functional llvm-spirv converter. The converter must produce LLVM IR in format which pocl’s LLVM can consume, so e.g. using llvm-spirv builf from branch “spirv-3.6.1” against pocl built with LLVM 5 is unlikely to work. However, here is now a “spirv-6.0” branch in the official SPIRV-LLVM Khronos repository, and its llvm-spirv + pocl + LLVM 6 seem to pass some quick tests.

Compiling from OpenCL sources to SPIR:

> clang -D_CL_DISABLE_HALF -Xclang -cl-std=CL1.2 -D__OPENCL_C_VERSION__=120 -D__OPENCL_VERSION__=120 -Dcl_khr_int64 -Dcl_khr_byte_addressable_store -Dcl_khr_global_int32_base_atomics -Dcl_khr_global_int32_extended_atomics -Dcl_khr_local_int32_base_atomics -Dcl_khr_local_int32_extended_atomics -Dcl_khr_3d_image_writes -Dcl_khr_fp64 -Dcl_khr_int64_base_atomics -Dcl_khr_int64_extended_atomics -emit-llvm -target spir64-unknown-unknown -o SPIR_OUTPUT.bc -x cl -c SOURCE.cl -include <POCL_SOURCE_DIR>/include/_kernel.h -include <POCL_SOURCE_DIR>/include/_enable_all_exts.h