Reduce build warnings: fix field reordering and conditionally drop isystem w/a

[Silv3S]

• Conditionally remove isystem flags, as they don't silence any warnings and also throw extra warnings per each kernel:

c++: warning: /opt/intel/oneapi/compiler/2025.3/include/sycl: linker input file unused because linking not done

• Fix no-reorder warning

[Copilot]

Pull request overview

This PR silences build warnings by removing workaround code for SYCL header warnings and explicitly disabling specific warning categories that flood build logs.

• Removes the -isystem flag workaround for SYCL headers which was causing linker warnings
• Adds explicit warning suppressions for -Wno-attributes and -Wno-reorder to reduce build log noise

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[dvrogozh]

Please, help to CC people who made the initial change for review and feedback. Use git-blame to find.

-isystem did work for us. It has silenced warnings for the code in SYCL headers and exposed actual warning for our kernels. The plan was and is to further fix remainder warnings. The warnings you observe, are they against SYCL headers code or against our own kernel we host in this project? If the former - something had stopped working for -isystem trick and we need to find root cause. If the later - warnings for our own kernels needs to be fixed, not silenced!

[Silv3S]

@dvrogozh thanks for review. I removed -isystem as it doesn't silence any SYCL warnings. Also it floods build logs with this warning, repeated for each kernel:

# With patch
[7178/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationLeakyReluKernels_gen_ActivationLeakyReluKernels.cpp.o
c++: warning: /opt/intel/oneapi/compiler/2025.3/include/sycl: linker input file unused because linking not done
[7179/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationHardsigmoidKernels_gen_ActivationHardsigmoidKernels.cpp.o
c++: warning: /opt/intel/oneapi/compiler/2025.3/include/sycl: linker input file unused because linking not done
[7180/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationLogSigmoidKernels_gen_ActivationLogSigmoidKernels.cpp.o
c++: warning: /opt/intel/oneapi/compiler/2025.3/include/sycl: linker input file unused because linking not done

# With patch removed
[7178/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationLeakyReluKernels_gen_ActivationLeakyReluKernels.cpp.o
[7179/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationSoftplusKernels_gen_ActivationSoftplusKernels.cpp.o
[7180/8426] Building SYCL (Device) object torch-xpu-ops-sycl-ActivationGeluKernel_gen_ActivationGeluKernel.cpp.o

Regarding warnings which I wanted to silence - they are visible with and without -isystem. For example in some unrelated CI Linux build https://github.com/intel/torch-xpu-ops/actions/runs/19564034097/job/56030166103#step:6:13194

/home/jenkins/actions-runner/_work/torch-xpu-ops/torch-xpu-ops/pytorch/third_party/torch-xpu-ops/src/ATen/native/xpu/sycl/SortingKernels.h:19:30: warning: ‘sycl::reqd_sub_group_size’ scoped attribute directive ignored [-Wattributes]
   19 |       sycl::nd_item<1> item) const {
      |                              ^~~~~
/home/jenkins/actions-runner/_work/torch-xpu-ops/torch-xpu-ops/pytorch/third_party/torch-xpu-ops/src/ATen/native/xpu/sycl/SortingKernels.h:100:30: warning: ‘sycl::reqd_sub_group_size’ scoped attribute directive ignored [-Wattributes]
  100 |       sycl::nd_item<1> item) const {

and

/tmp/icx-582c2a1559/FusedSgdKernels-header-93eb53.h:122:40: warning: ‘visibility’ attribute ignored [-Wattributes]
  122 |   static constexpr const char* getName() { return "_ZTSN2at6native3xpu29MultiTensorApplyKernelFunctorIPNS1_16TLMetaForAddressILi2EEEPNS1_11TLMetaForWGENS1_12_GLOBAL__N_119FusedSgdMathFunctorIdLi2EEEJddPKfddbbbSC_SC_EEE"; }
      |                                        ^
/tmp/icx-582c2a1559/FusedSgdKernels-header-93eb53.h:124:42: warning: ‘visibility’ attribute ignored [-Wattributes]
  124 |   static constexpr unsigned getNumParams() { return 6; }
      |                                          ^
/tmp/icx-582c2a1559/FusedSgdKernels-header-93eb53.h:126:70: warning: ‘visibility’ attribute ignored [-Wattributes]
  126 |   static constexpr const kernel_param_desc_t& getParamDesc(unsigned i) {

[dvrogozh]

Regarding warnings which I wanted to silence - they are visible with and without -isystem

Are you using oneapi 2025.3? If yes, then the behavior you observe is expected as this is the first version which does not need the -isystem workaround. Earlier versions of the compiler, i.e. oneapi 2025.2, 2025.1 and below, has an issue that it flooded output with warnings on SYCL headers themselves which are unrelated to our sycl code. The workaround to fix that is to add -isystem.

If you are using 2025.3, then I suggest that we should protect adding -isystem with the oneapi version check and avoid adding it for 2025.3+.

As for the warning examples you've posted, I believe these are legitimate warnings for our code in this repository and such warnings needs to be fixed rather than silenced. If we can't fix them for whatever reason we first need to raise issue with oneapi team and only then consider silencing them.

[Silv3S]

Yes, I used 2025.3 for tests, that's why I didn't observe any difference. As you proposed I kept isystem flag guarded by oneAPI check to keep this workaround for older compiler versions.

[dvrogozh]

@Silv3S , thank you for update. Last comment from my side, I think PR title "Reduce build warnings by removing w/a for older compilers" went out of sync with actual content as PR now fixes reordering warnings in one kernel and updates wa. Can you, please, align the PR title?

[dvrogozh]

LGTM

[Silv3S]

@guangyey could you please merge?

[guangyey]

OK, why not.