Fix [[nodiscard]] build errors and BUCK deps across comms, gloo, caffe2 by gyllstromk · Pull Request #960 · meta-pytorch/torchcomms

gyllstromk · 2026-03-06T01:16:04Z

Summary:
ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy,
hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree,
hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with
[[nodiscard]]. Combined with -Werror, this causes build failures wherever
return values are discarded.

Originally discovered building with ROCm 7.2 headers, but confirmed to
also affect ROCm 7.0 builds (reported independently by yvliu and hqguo).
The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP
headers — the fix is the same for both versions.

Changes:

Add (void) casts to suppress [[nodiscard]] warnings across comms/
(tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files
Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client
with common:common) and comms/tcp_devmem/unpack (explicit glog dep path)
that surface when building these targets under ROCm constraints

The (void) casts are no-ops on CUDA and older ROCm — safe to land
regardless of ROCm version.

Reviewed By: bbeckca

Differential Revision: D93759269

meta-codesync · 2026-03-06T23:57:23Z

@gyllstromk has exported this pull request. If you are a Meta employee, you can view the originating Diff in D93759269.

Summary: X-link: meta-pytorch/torchcomms#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…omms, gloo, caffe2 (#176671) Summary: X-link: pytorch/gloo#494 X-link: meta-pytorch/torchcomms#960 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Test Plan: ## Reproducing the [[nodiscard]] build errors (ROCm 7.0+) ROCm 7.0 HIP headers annotate CUDA-mapped API functions with `[[nodiscard]]` (e.g. `hipStreamDestroy`, `hipSetDevice`, `hipFree`). With `-Werror` enabled, any call site that discards the return value fails to compile: ``` error: ignoring return value of function declared with 'nodiscard' attribute [-Werror,-Wunused-result] cudaSetDevice(device); ^~~~~~~~~~~~~~~~~~~~~~ ``` To reproduce, build any affected target with ROCm >= 7.0. Example using the gloo HIP collectives (which calls `cudaSetDevice` and `cudaDeviceEnablePeerAccess` without checking the return value): ```bash hipcc -std=c++17 -Werror \ -I<pytorch_root> -I<rocm_7.0_path>/include \ -c gloo/cuda_collectives_native.h # → error: ignoring return value ... [-Werror,-Wunused-result] ``` The fix adds `(void)` casts to explicitly discard the return value, which is the standard C++ pattern for suppressing `[[nodiscard]]` warnings. The casts are no-ops on CUDA and older ROCm versions. ## Verification (fbcode, mode/amd-gpu with ROCm 7.0 headers) ```bash # ctran (ibutils.cc, LogInit.cc) buck2 build mode/amd-gpu fbcode//comms/ctran/backends/ib:ib buck2 build mode/amd-gpu fbcode//comms/ctran/utils:utils # rcclx (cudawrap.cc, register.cc, RcclxScubaLogger.h) buck2 build mode/amd-gpu fbcode//comms/rcclx:rcclx-dev # tcp_devmem (batch_unpack_producer.cc, shared_region.cc) buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/unpack:batch_unpack_producer buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/common:common # gloo (cuda_collectives_native.h) buck2 build mode/amd-gpu fbcode//gloo:gloo_gpu_hip ``` All targets build successfully. The BUCK dep fixes for `comms/tcp_devmem/nccl` (nccl-gen, nccl-sim) and `comms/tcp_devmem/unpack` resolve link-time errors that surface when building under ROCm constraints. Reviewed By: bbeckca Differential Revision: D93759269

…e2 (pytorch#494) Summary: X-link: meta-pytorch/torchcomms#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…omms, gloo, caffe2 (pytorch#176671) Summary: X-link: pytorch/gloo#494 X-link: meta-pytorch/torchcomms#960 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Test Plan: ## Reproducing the [[nodiscard]] build errors (ROCm 7.0+) ROCm 7.0 HIP headers annotate CUDA-mapped API functions with `[[nodiscard]]` (e.g. `hipStreamDestroy`, `hipSetDevice`, `hipFree`). With `-Werror` enabled, any call site that discards the return value fails to compile: ``` error: ignoring return value of function declared with 'nodiscard' attribute [-Werror,-Wunused-result] cudaSetDevice(device); ^~~~~~~~~~~~~~~~~~~~~~ ``` To reproduce, build any affected target with ROCm >= 7.0. Example using the gloo HIP collectives (which calls `cudaSetDevice` and `cudaDeviceEnablePeerAccess` without checking the return value): ```bash hipcc -std=c++17 -Werror \ -I<pytorch_root> -I<rocm_7.0_path>/include \ -c gloo/cuda_collectives_native.h # → error: ignoring return value ... [-Werror,-Wunused-result] ``` The fix adds `(void)` casts to explicitly discard the return value, which is the standard C++ pattern for suppressing `[[nodiscard]]` warnings. The casts are no-ops on CUDA and older ROCm versions. ## Verification (fbcode, mode/amd-gpu with ROCm 7.0 headers) ```bash # ctran (ibutils.cc, LogInit.cc) buck2 build mode/amd-gpu fbcode//comms/ctran/backends/ib:ib buck2 build mode/amd-gpu fbcode//comms/ctran/utils:utils # rcclx (cudawrap.cc, register.cc, RcclxScubaLogger.h) buck2 build mode/amd-gpu fbcode//comms/rcclx:rcclx-dev # tcp_devmem (batch_unpack_producer.cc, shared_region.cc) buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/unpack:batch_unpack_producer buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/common:common # gloo (cuda_collectives_native.h) buck2 build mode/amd-gpu fbcode//gloo:gloo_gpu_hip ``` All targets build successfully. The BUCK dep fixes for `comms/tcp_devmem/nccl` (nccl-gen, nccl-sim) and `comms/tcp_devmem/unpack` resolve link-time errors that surface when building under ROCm constraints. Reviewed By: bbeckca Differential Revision: D93759269

…e2 (pytorch#494) Summary: Pull Request resolved: pytorch#494 X-link: meta-pytorch/torchcomms#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…omms, gloo, caffe2 (pytorch#176671) Summary: X-link: pytorch/gloo#494 X-link: meta-pytorch/torchcomms#960 Pull Request resolved: pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Test Plan: ## Reproducing the [[nodiscard]] build errors (ROCm 7.0+) ROCm 7.0 HIP headers annotate CUDA-mapped API functions with `[[nodiscard]]` (e.g. `hipStreamDestroy`, `hipSetDevice`, `hipFree`). With `-Werror` enabled, any call site that discards the return value fails to compile: ``` error: ignoring return value of function declared with 'nodiscard' attribute [-Werror,-Wunused-result] cudaSetDevice(device); ^~~~~~~~~~~~~~~~~~~~~~ ``` To reproduce, build any affected target with ROCm >= 7.0. Example using the gloo HIP collectives (which calls `cudaSetDevice` and `cudaDeviceEnablePeerAccess` without checking the return value): ```bash hipcc -std=c++17 -Werror \ -I<pytorch_root> -I<rocm_7.0_path>/include \ -c gloo/cuda_collectives_native.h # → error: ignoring return value ... [-Werror,-Wunused-result] ``` The fix adds `(void)` casts to explicitly discard the return value, which is the standard C++ pattern for suppressing `[[nodiscard]]` warnings. The casts are no-ops on CUDA and older ROCm versions. ## Verification (fbcode, mode/amd-gpu with ROCm 7.0 headers) ```bash # ctran (ibutils.cc, LogInit.cc) buck2 build mode/amd-gpu fbcode//comms/ctran/backends/ib:ib buck2 build mode/amd-gpu fbcode//comms/ctran/utils:utils # rcclx (cudawrap.cc, register.cc, RcclxScubaLogger.h) buck2 build mode/amd-gpu fbcode//comms/rcclx:rcclx-dev # tcp_devmem (batch_unpack_producer.cc, shared_region.cc) buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/unpack:batch_unpack_producer buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/common:common # gloo (cuda_collectives_native.h) buck2 build mode/amd-gpu fbcode//gloo:gloo_gpu_hip ``` All targets build successfully. The BUCK dep fixes for `comms/tcp_devmem/nccl` (nccl-gen, nccl-sim) and `comms/tcp_devmem/unpack` resolve link-time errors that surface when building under ROCm constraints. Reviewed By: bbeckca Differential Revision: D93759269

…e2 (pytorch#494) Summary: X-link: meta-pytorch/torchcomms#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…omms, gloo, caffe2 (pytorch#176671) Summary: X-link: pytorch/gloo#494 X-link: meta-pytorch/torchcomms#960 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Test Plan: ## Reproducing the [[nodiscard]] build errors (ROCm 7.0+) ROCm 7.0 HIP headers annotate CUDA-mapped API functions with `[[nodiscard]]` (e.g. `hipStreamDestroy`, `hipSetDevice`, `hipFree`). With `-Werror` enabled, any call site that discards the return value fails to compile: ``` error: ignoring return value of function declared with 'nodiscard' attribute [-Werror,-Wunused-result] cudaSetDevice(device); ^~~~~~~~~~~~~~~~~~~~~~ ``` To reproduce, build any affected target with ROCm >= 7.0. Example using the gloo HIP collectives (which calls `cudaSetDevice` and `cudaDeviceEnablePeerAccess` without checking the return value): ```bash hipcc -std=c++17 -Werror \ -I<pytorch_root> -I<rocm_7.0_path>/include \ -c gloo/cuda_collectives_native.h # → error: ignoring return value ... [-Werror,-Wunused-result] ``` The fix adds `(void)` casts to explicitly discard the return value, which is the standard C++ pattern for suppressing `[[nodiscard]]` warnings. The casts are no-ops on CUDA and older ROCm versions. ## Verification (fbcode, mode/amd-gpu with ROCm 7.0 headers) ```bash # ctran (ibutils.cc, LogInit.cc) buck2 build mode/amd-gpu fbcode//comms/ctran/backends/ib:ib buck2 build mode/amd-gpu fbcode//comms/ctran/utils:utils # rcclx (cudawrap.cc, register.cc, RcclxScubaLogger.h) buck2 build mode/amd-gpu fbcode//comms/rcclx:rcclx-dev # tcp_devmem (batch_unpack_producer.cc, shared_region.cc) buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/unpack:batch_unpack_producer buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/common:common # gloo (cuda_collectives_native.h) buck2 build mode/amd-gpu fbcode//gloo:gloo_gpu_hip ``` All targets build successfully. The BUCK dep fixes for `comms/tcp_devmem/nccl` (nccl-gen, nccl-sim) and `comms/tcp_devmem/unpack` resolve link-time errors that surface when building under ROCm constraints. Reviewed By: bbeckca Differential Revision: D93759269

…e2 (meta-pytorch#960) Summary: X-link: pytorch/gloo#494 Pull Request resolved: meta-pytorch#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…e2 (pytorch#494) Summary: Pull Request resolved: pytorch#494 X-link: meta-pytorch/torchcomms#960 X-link: pytorch/pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Reviewed By: bbeckca Differential Revision: D93759269

…omms, gloo, caffe2 (pytorch#176671) Summary: X-link: pytorch/gloo#494 X-link: meta-pytorch/torchcomms#960 Pull Request resolved: pytorch#176671 ROCm 7.0+ HIP headers annotate API functions (hipStreamDestroy, hipMemcpyAsync, hipStreamSynchronize, hipSetDevice, hipGetDevice, hipFree, hipHostUnregister, hipDeviceEnablePeerAccess, cuGetErrorString) with [[nodiscard]]. Combined with -Werror, this causes build failures wherever return values are discarded. Originally discovered building with ROCm 7.2 headers, but confirmed to also affect ROCm 7.0 builds (reported independently by yvliu and hqguo). The [[nodiscard]] attribute is present in both ROCm 7.0 and 7.2 HIP headers — the fix is the same for both versions. Changes: - Add (void) casts to suppress [[nodiscard]] warnings across comms/ (tcp_devmem, ctran, rcclx), gloo/, and caffe2/ (nativert) — 12 C++ files - Fix BUCK dependency issues in comms/tcp_devmem/nccl (replace devmgr-client with common:common) and comms/tcp_devmem/unpack (explicit glog dep path) that surface when building these targets under ROCm constraints The (void) casts are no-ops on CUDA and older ROCm — safe to land regardless of ROCm version. Test Plan: ## Reproducing the [[nodiscard]] build errors (ROCm 7.0+) ROCm 7.0 HIP headers annotate CUDA-mapped API functions with `[[nodiscard]]` (e.g. `hipStreamDestroy`, `hipSetDevice`, `hipFree`). With `-Werror` enabled, any call site that discards the return value fails to compile: ``` error: ignoring return value of function declared with 'nodiscard' attribute [-Werror,-Wunused-result] cudaSetDevice(device); ^~~~~~~~~~~~~~~~~~~~~~ ``` To reproduce, build any affected target with ROCm >= 7.0. Example using the gloo HIP collectives (which calls `cudaSetDevice` and `cudaDeviceEnablePeerAccess` without checking the return value): ```bash hipcc -std=c++17 -Werror \ -I<pytorch_root> -I<rocm_7.0_path>/include \ -c gloo/cuda_collectives_native.h # → error: ignoring return value ... [-Werror,-Wunused-result] ``` The fix adds `(void)` casts to explicitly discard the return value, which is the standard C++ pattern for suppressing `[[nodiscard]]` warnings. The casts are no-ops on CUDA and older ROCm versions. ## Verification (fbcode, mode/amd-gpu with ROCm 7.0 headers) ```bash # ctran (ibutils.cc, LogInit.cc) buck2 build mode/amd-gpu fbcode//comms/ctran/backends/ib:ib buck2 build mode/amd-gpu fbcode//comms/ctran/utils:utils # rcclx (cudawrap.cc, register.cc, RcclxScubaLogger.h) buck2 build mode/amd-gpu fbcode//comms/rcclx:rcclx-dev # tcp_devmem (batch_unpack_producer.cc, shared_region.cc) buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/unpack:batch_unpack_producer buck2 build mode/amd-gpu fbcode//comms/tcp_devmem/common:common # gloo (cuda_collectives_native.h) buck2 build mode/amd-gpu fbcode//gloo:gloo_gpu_hip ``` All targets build successfully. The BUCK dep fixes for `comms/tcp_devmem/nccl` (nccl-gen, nccl-sim) and `comms/tcp_devmem/unpack` resolve link-time errors that surface when building under ROCm constraints. Reviewed By: bbeckca Differential Revision: D93759269

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Fix [[nodiscard]] build errors and BUCK deps across comms, gloo, caffe2#960

Fix [[nodiscard]] build errors and BUCK deps across comms, gloo, caffe2#960
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