Work around missing OpenCL headers in Intel Windows conda package - #3010
Merged
Conversation
antonwolfy
requested review from
ndgrigorian and
vlad-perevezentsev
as code owners
July 30, 2026 10:37
Starting with Intel oneAPI 2026.1.1, the `intel-sycl-rt` conda package no
longer bundles the OpenCL headers (`CL/cl.h`), which the SYCL headers still
`#include`. On Linux the package gained an explicit `opencl-headers` run
dependency (INST-26476), so the header is pulled in transitively and the
build keeps working. The Windows package dropped the headers without adding
that dependency, so the backend now fails to compile with:
fatal error: 'CL/cl.h' file not found
Add `opencl-headers` as a host dependency on Windows to pull the header in
from conda-forge (it installs to `%PREFIX%\Library\include\CL\cl.h`, already
on the compiler include path). This is a workaround until the Intel Windows
`intel-sycl-rt` package is fixed to match the Linux dependency.
antonwolfy
force-pushed
the
workaround-win-opencl-headers
branch
from
July 30, 2026 10:48
58af9fd to
71ef5e1
Compare
Contributor
|
View rendered docs @ https://intelpython.github.io/dpnp/index.html |
Contributor
|
Array API standard conformance tests for dpnp=0.21.0dev3=py314h509198e_17 ran successfully. |
Collaborator
|
coverage: 78.406%. remained the same — workaround-win-opencl-headers into master |
vlad-perevezentsev
self-requested a review
July 30, 2026 12:35
vlad-perevezentsev
approved these changes
Jul 30, 2026
vlad-perevezentsev
left a comment
vlad-perevezentsev
left a comment
Contributor
There was a problem hiding this comment.
LGTM
Thank you @antonwolfy
github-actions Bot
added a commit
that referenced
this pull request
Jul 30, 2026
) ## Summary The Windows conda build currently fails while compiling the C++/SYCL backend: ``` %PREFIX%\Library\include\sycl\detail\cl.h(22,10): fatal error: 'CL/cl.h' file not found 22 | #include <CL/cl.h> ``` This is **not** a dpnp source issue — it is an Intel oneAPI packaging regression. This PR adds a workaround so the Windows build succeeds again. ## Root cause Starting with Intel oneAPI **2026.1.1**, the `intel-sycl-rt` conda package no longer bundles the OpenCL headers (`CL/cl.h` and the rest of `include/CL/*.h`), even though the SYCL headers still `#include <CL/cl.h>`. This change was done by the packaging team to avoid conda `ClobberWarnings` against conda-forge's `opencl-headers`/`ocl-icd`. The fix was applied **asymmetrically** across platforms: | `intel-sycl-rt` | Ships `CL/cl.h`? | `opencl-headers` dependency? | dpnp build | |---|---|---|---| | Linux `2026.1.1-intel_325` | ❌ removed | ✅ `depends: opencl-headers >=2025.06.13` | ✅ passes | | Windows `2026.1.1-intel_327` | ❌ removed | ❌ **none** | ❌ fails | So on Linux the header is still pulled in transitively via the new `opencl-headers` dependency, while on Windows nothing provides `CL/cl.h` and the backend fails to compile. ## Change Add `opencl-headers` as a host dependency on Windows only: ```yaml - opencl-headers # [win] ``` conda-forge's `opencl-headers` installs `CL/cl.h` to `%PREFIX%\Library\include\CL\cl.h`, which is already on the compiler include path (`-external:I%PREFIX%\Library\include`), so no build-script change is needed. Linux is left untouched since it already gets the header transitively. ## Follow-up This is a workaround. The proper fix is upstream: the Windows `intel-sycl-rt` package should gain the same `opencl-headers` run dependency that the Linux package received. Once that ships, this workaround can be removed. ffc6747
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
The Windows conda build currently fails while compiling the C++/SYCL backend:
This is not a dpnp source issue — it is an Intel oneAPI packaging regression. This PR adds a workaround so the Windows build succeeds again.
Root cause
Starting with Intel oneAPI 2026.1.1, the
intel-sycl-rtconda package no longer bundles the OpenCL headers (CL/cl.hand the rest ofinclude/CL/*.h), even though the SYCL headers still#include <CL/cl.h>. This change was done by the packaging team to avoid condaClobberWarningsagainst conda-forge'sopencl-headers/ocl-icd.The fix was applied asymmetrically across platforms:
intel-sycl-rtCL/cl.h?opencl-headersdependency?2026.1.1-intel_325depends: opencl-headers >=2025.06.132026.1.1-intel_327So on Linux the header is still pulled in transitively via the new
opencl-headersdependency, while on Windows nothing providesCL/cl.hand the backend fails to compile.Change
Add
opencl-headersas a host dependency on Windows only:conda-forge's
opencl-headersinstallsCL/cl.hto%PREFIX%\Library\include\CL\cl.h, which is already on the compiler include path (-external:I%PREFIX%\Library\include), so no build-script change is needed. Linux is left untouched since it already gets the header transitively.Follow-up
This is a workaround. The proper fix is upstream: the Windows
intel-sycl-rtpackage should gain the sameopencl-headersrun dependency that the Linux package received. Once that ships, this workaround can be removed.