[mlir][spirv][gpu] Add lowering for `gpu.subgroup_broadcast`

[kuhar]

We are missing SPIR-V lowering patterns for the gpu.subgroup_broadcast op. These be added to to https://github.com/llvm/llvm-project/blob/main/mlir/lib/Conversion/GPUToSPIRV/GPUToSPIRV.cpp

We have two cases:

1. gpu.subgroup_broadcast specific_lane --> spirv.GroupNonUniformBroadcast
2. gpu.subgroup_broadcast first_lane -> spirv.GroupNonUniformBroadcastFirst https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#OpGroupNonUniformBroadcastFirst

Plain broadcast exists in the SPIR-V dialect, broadcast first lane needs to be added.

[llvmbot]

@llvm/issue-subscribers-mlir-spirv

Author: Jakub Kuderski (kuhar)

We are missing SPIR-V lowering patterns for the [`gpu.subgroup_broadcast` op](https://mlir.llvm.org/docs/Dialects/GPU/#gpusubgroup_broadcast-gpusubgroupbroadcastop). These be added to to https://github.com/llvm/llvm-project/blob/main/mlir/lib/Conversion/GPUToSPIRV/GPUToSPIRV.cpp

We have two cases:

1. gpu.subgroup_broadcast specific_lane --> spirv.GroupNonUniformBroadcast
2. gpu.subgroup_broadcast first_lane -> spirv.GroupNonUniformBroadcastFirst https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#OpGroupNonUniformBroadcastFirst

Plain broadcast exists in the SPIR-V dialect, broadcast lane needs to be added.

[llvmbot]

@llvm/issue-subscribers-mlir-gpu

Author: Jakub Kuderski (kuhar)

We are missing SPIR-V lowering patterns for the [`gpu.subgroup_broadcast` op](https://mlir.llvm.org/docs/Dialects/GPU/#gpusubgroup_broadcast-gpusubgroupbroadcastop). These be added to to https://github.com/llvm/llvm-project/blob/main/mlir/lib/Conversion/GPUToSPIRV/GPUToSPIRV.cpp

We have two cases:

1. gpu.subgroup_broadcast specific_lane --> spirv.GroupNonUniformBroadcast
2. gpu.subgroup_broadcast first_lane -> spirv.GroupNonUniformBroadcastFirst https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#OpGroupNonUniformBroadcastFirst

Plain broadcast exists in the SPIR-V dialect, broadcast lane needs to be added.

[Rayfxl]

Is anyone currently working on this issue? If not, I’d be happy to take it.

[itikhono]

@Rayfxl hi! have you started to work on this? if not, may I take it?

[Rayfxl]

@Rayfxl hi! have you started to work on this? if not, may I take it?

I was planning to work on this, but I haven’t started yet due to being busy with work. I’m not sure if anyone else has picked it up, so please feel free to take it if you’d like.