[SYCL][clang-linker-wrapper] Fix argument parsing in Clang Linker Wrapper #20470

YixingZhang007 · 2025-10-25T03:28:30Z

This patch resolves failures in SYCL E2E tests fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp when using the new offloading model by addressing two issues:

(1) The original implementation in the ClangLinkerWrapper.cpp incorrectly constructed ocloc command line arguments by concatenating all arguments into a single string; this caused parsing failures in the executor. This is fixed in this patch by splitting arguments on whitespace boundaries and rejoining them into a correctly formatted command string.

(2) The double-precision variable test case in fp64-conv-emu-2.cpp has been temporarily disabled because the current implementation only supports -fsycl-fp64-conv-emu, which provides limited FP64 emulation for kernels containing FP64 conversions but no FP64 computations. The test will be re-enabled once -fsycl-fp64-gen-emu (full FP64 emulation) is implemented.

… new offloading model

aelovikov-intel

E2E tests LGTM

maarquitos14 · 2025-10-27T13:54:37Z

clang/lib/Driver/Driver.cpp

+  /// Otherwise return 'false'.
+bool Driver::GetUseNewOffloadDriverForSYCLOffload(Compilation &C,
+                                                  const ArgList &Args) const {
+  // Check only if enabled with -fsycl


Suggested change

// Check only if enabled with -fsycl

// Check only if enabled with -fsycl.

Thank you for your suggestions! The changes for enabling the new offloading model in this PR were copied directly from another PR (#15121). This PR specifically focuses on resolving test failures in fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp that occur after enabling the new offloading model. I will move any comments related to the new offloading model changes to the original PR where that functionality was implemented. The changes related to enabling the new offloading model have been reverted and removed from this PR.

maarquitos14 · 2025-10-27T13:56:49Z

clang/lib/Driver/Driver.cpp

+  /// Utility function to parse all devices passed via -fsycl-targets.
+  /// Return 'true' for JIT, AOT Intel CPU/GPUs and NVidia/AMD targets.
+  /// Otherwise return 'false'.
+bool Driver::GetUseNewOffloadDriverForSYCLOffload(Compilation &C,


I think the name doesn't describe very well what the function is doing, or at least doesn't align very well with the description in the comment above. I would expect something including the words Get and Devices at least.

Please refer to the previous comment as well :)

maarquitos14 · 2025-10-27T14:38:43Z

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

+    if (!BeforeOptions.empty()){
+      SmallVector<StringRef, 8> BeforeArgs;
+      BeforeOptions.split(BeforeArgs, " ", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+      for (auto string : BeforeArgs) {


This is most likely introducing a copy for each arg. Can we try const auto & instead?

Thanks for your suggestions! I have made the change.

maarquitos14 · 2025-10-27T14:40:14Z

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

-      CmdArgs.push_back(Args.MakeArgString(Replace));
+      SmallVector<StringRef, 8> AfterArgs;
+      AfterOptions.split(AfterArgs, " ", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+      std::string JoinedOptions = llvm::join(AfterArgs, " ");


Does this pass all tests? It was similar to this before and I had to add the , because it was causing trouble with ocloc. I added a specific test for that, so if it is passing, then I'm good.

The tests that were previously failing for the clang-linker-wrapper issue (fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp) are now passing. The tests currently failing in CI (such as https://github.com/intel/llvm/actions/runs/18854382403/job/53800150157) for the new offloading model are unrelated to this issue and will be addressed in future PRs. I am wondering which one is the test you mentioned adding for this issue? I'm not sure if you're referring to https://github.com/intel/llvm/blob/sycl/sycl/test-e2e/SYCLBIN/simple_kernel_aot; this test is passing with the current changes.

@YixingZhang007 , did you run entire SYCL E2E with new offloading model and your changes? Comparing with Justin's result, any regressions, or only 2 more passes?

Hello Yury! Yes, I have run the entire SYCL E2E tests with new offloading model and my change (the result can also found at https://github.com/intel/llvm/actions/runs/18854382403/job/53800150157 , this is the CI before removing the new offloading model changes from this PR). Comparing with Justin's result, I haven't seen any regression and the 2 tests (fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp) are passing.

thanks, that addresses my concern.

maarquitos14 · 2025-10-27T14:41:12Z

sycl/test-e2e/OptionalKernelFeatures/fp64-conv-emu-1.cpp

 // RUN: %clangxx -fsycl -fsycl-targets=intel_gpu_dg2_g10,intel_gpu_dg2_g11,intel_gpu_dg2_g12,intel_gpu_pvc,intel_gpu_mtl_h,intel_gpu_mtl_u -fsycl-fp64-conv-emu %O0 %s -o %t.out
 // RUN: %{run} %t.out

+// RUN: %clangxx -fsycl -fsycl-targets=intel_gpu_dg2_g10,intel_gpu_dg2_g11,intel_gpu_dg2_g12,intel_gpu_pvc,intel_gpu_mtl_h,intel_gpu_mtl_u -fsycl-fp64-conv-emu --offload-new-driver %O0 %s -o %t.out


Could we also try with -g? The code you're changing used to have issues with -g, so just to be on the safe side.

The changes work with '-g' and I have also added a new test command in this file for running the test with -g. Thank you!

continue my previous comment: we can keep -g test, but just removing --offload-new-driver.

srividya-sundaram · 2025-10-28T21:36:56Z

clang/lib/Driver/Driver.cpp

+                   options::OPT_offload_new_driver, false))
+    return false;
+
+  if (Args.hasArg(options::OPT_fintelfpga))


Support for FPGA related options have been removed in this PR.
Don't think this check is necessary.

Thank you for your suggestions! The changes for enabling the new offloading model in this PR were copied directly from another PR (#15121). This PR specifically focuses on resolving test failures in fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp that occur after enabling the new offloading model. I will move any comments related to the new offloading model changes to the original PR where that functionality was implemented. The changes related to enabling the new offloading model have been reverted and removed from this PR.

sarnex

lgtm but will fall back to marcos for the in-depth review

sarnex · 2025-10-29T15:15:45Z

sycl/test-e2e/OptionalKernelFeatures/fp64-conv-emu-2.cpp

-  if (q.get_device().has(aspect::fp64))
-    nfail += test<Increment<double>>(q);
+  // This test is currently disabled because it requires the -ze-fp64-gen-emu
+  // IGC option to run FP64 arithmetic operations. The -fsycl-fp64-conv-emu flag


sorry why are we seeing this failure now?

Thanks for pointing this out! We are seeing the following failure with this test when we enable the new offloading model (after applying changes from #15121). The error generated is as below.

Double arithmetic operation is not supported on this platform with FP64 conversion emulation mode (poison FP64 kernels is disabled). in kernel: 'typeinfo name for int test<Increment<double>>(sycl::_V1::queue&)::'lambda'(sycl::_V1::handler&)::operator()(sycl::_V1::handler&) const::'lambda'()'

I think this error occurs because this test performs arithmetic operations with double-precision variables, which should only be permitted when the -ze-fp64-gen-emu IGC option is not enabled. The currently enabled -ze-fp64-gen-conv-emu option (activated by -fsycl-fp64-conv-emu flag that we passed into clang) should only allow FP64 conversions, not FP64 computations.

Sorry, I have the same question, and I still do not understand: how does this test pass with old offloading model then?

I wasn't able to figure out how the old offloading model is able to pass this, but I have checked that the old offloading model only has -ze-fp64-gen-conv-emu passed into ocloc which should not be sufficient. I think this failure for the old offloading model did not get captured for some issue that would need more investigation (I can definitely look more into this if needed). But I have tried passing -ze-fp64-gen-emu into the ocloc command while running the test with the new offloading model, and this helps solve the issue, and also according to the previous documentation and PRs (such as #13912), I think the option -ze-fp64-gen-emu is required for this test to have arithmetic operations on double numbers. Thank you :)

I think we need to figure out how the test is passing, before disabling anything in the code.
Currently the test is passing, but with your change, this scenario will be excluded from testing for the old offloading model, which doesn't look good to me.

the new/old offloading model shouldnt change the content of any IR, it should just change the tools called (which shouldn't effect IR content either) and the arguments to the tools, so it may be easy to see if there is some difference in args to ocloc or different image compile/link flags or something.

sarnex · 2025-10-29T15:16:05Z

clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp

-    if (!BeforeOptions.empty())
-      CmdArgs.push_back(BeforeOptions);
+    if (!BeforeOptions.empty()) {
+      SmallVector<StringRef, 8> BeforeArgs;


also just wondering, i see one of your commits is titled says 'revert nick's PR' but i don't remember writing that code so if it is referring to me do you mind linking the PR being reverted, thanks

Absolutely! I previously applied the changes directly from your PR #15121 (this PR is currently closed) to enable the new offloading model and verify the CI test results. After confirming that both fp64-conv-emu-1.cpp and fp64-conv-emu-2.cpp passed in CI with the new offloading model enabled, I reverted the changes. If my understanding is correct, I think we would enable the new offloading model changes after the other SYCL E2E test failures are resolved.

I believe, resolving all SYCL E2E test failures with new offloading model is necessary to enable new model by default, but it is not the only condition.
I think as soon as SYCL E2E pass, we want to enable regular testing (pre-commit? post-commit? nightly?) with new offloading model to make sure no regressions.
Or we might want to even enable it now and mark not-passing tests as XFAIL.
Thoughts?

I would say we should add it to the nightly, but yeah IMO we can do it now if someone has bandwidth do to it. i definitely do not but im happy to help. We need the job to pass though, so we ideally would have a LIT variable so we can XFAIL the failing ones, or more crudely we coukd have some file with a list of either passing or failing tests, in that case we could use LIT_FILTER or LIT_FILTER_OUT

btw that pr isn't from me but doesnt matter either way :P

YuriPlyakhin · 2025-10-29T18:04:18Z

sycl/test-e2e/OptionalKernelFeatures/fp64-conv-emu-1.cpp

+// RUN: %clangxx -fsycl -fsycl-targets=intel_gpu_dg2_g10,intel_gpu_dg2_g11,intel_gpu_dg2_g12,intel_gpu_pvc,intel_gpu_mtl_h,intel_gpu_mtl_u -fsycl-fp64-conv-emu --no-offload-new-driver %O0 %s -o %t.out
+// RUN: %{run} %t.out


Question: do we want to modify this test that way by adding 2 command lines with and without offload new driver? It looks like that way we would modify a lot of tests introducing command lines like that and then when we switch to new offload driver by default, we would need to clean up all that.
I'm thinking would not it be better to just run entire SYCL E2E with new offload driver enabled, and mark currently failing tests as XFAIL? and when we are ready, we would just flip the switch and stop new offload driver testing (since it would become a default)
That way we would not need to modify all tests like that...

YixingZhang007 added 2 commits October 21, 2025 06:46

add nicks' commit

edae614

fix the ocloc issue for running the fp64-conv-emu-1.cpp test with the…

6340ea0

… new offloading model

YixingZhang007 requested review from a team as code owners October 25, 2025 03:28

YixingZhang007 requested a review from aelovikov-intel October 25, 2025 03:28

YixingZhang007 marked this pull request as draft October 25, 2025 03:28

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got the fp64-conv-emu-1.cpp test to pass

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aelovikov-intel reviewed Oct 27, 2025

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maarquitos14 reviewed Oct 27, 2025

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fix the issue in fp64-conv-emu-2.cpp test

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code clean up

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resolve CI failure

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YixingZhang007 mentioned this pull request Oct 28, 2025

Test new offload model #15121

Closed

YixingZhang007 changed the title ~~[NewOffloadModel] Fix argument parsing in Clang Linker Wrapper~~ [SYCL][clang-linker-wrapper] Fix argument parsing in Clang Linker Wrapper Oct 28, 2025

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revert Nick's PR

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resolve clang format failure

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resolve the clang format issue

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YixingZhang007 marked this pull request as ready for review October 29, 2025 04:14

sarnex approved these changes Oct 29, 2025

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	// Check only if enabled with -fsycl
	// Check only if enabled with -fsycl.

		// RUN: %clangxx -fsycl -fsycl-targets=intel_gpu_dg2_g10,intel_gpu_dg2_g11,intel_gpu_dg2_g12,intel_gpu_pvc,intel_gpu_mtl_h,intel_gpu_mtl_u -fsycl-fp64-conv-emu --no-offload-new-driver %O0 %s -o %t.out
		// RUN: %{run} %t.out

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[SYCL][clang-linker-wrapper] Fix argument parsing in Clang Linker Wrapper #20470

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[SYCL][clang-linker-wrapper] Fix argument parsing in Clang Linker Wrapper #20470

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