[Perf] Add cross-GPU subgroup.ballot(predicate) primitive#600
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[Perf] Add cross-GPU subgroup.ballot(predicate) primitive#600hughperkins wants to merge 1 commit intomainfrom
hughperkins wants to merge 1 commit intomainfrom
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Implement a portable ballot operation that returns a u32 bitmask where bit i is set if lane i's predicate is non-zero. Works across CUDA (__ballot_sync), AMDGPU (amdgcn_ballot.i32), and SPIR-V/Vulkan (OpGroupNonUniformBallot). Follows the same cross-backend pattern as subgroup.shuffle: a single Python API (subgroup.ballot) dispatches to the appropriate backend intrinsic at codegen time. On AMDGPU CDNA with 64-wide wavefronts only the low 32 bits are returned, consistent with the u32 return type.
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Implement a portable ballot operation that returns a u32 bitmask where bit i is set if lane i's predicate is non-zero. Works across CUDA (__ballot_sync), AMDGPU (amdgcn_ballot.i32), and SPIR-V/Vulkan (OpGroupNonUniformBallot).
Follows the same cross-backend pattern as subgroup.shuffle: a single Python API (subgroup.ballot) dispatches to the appropriate backend intrinsic at codegen time. On AMDGPU CDNA with 64-wide wavefronts only the low 32 bits are returned, consistent with the u32 return type.
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