Cleanup: remove some unused Cycles GPU code

To make porting to other architectures easier, clarifying that this does not
need to be supported. The unused parallel_reduce implementation assumed warp
size 32, but is easy to update if we ever need it in the future.

5 files changed, 0 insertions, 78 deletions

diff --git a/intern/cycles/kernel/CMakeLists.txt b/intern/cycles/kernel/CMakeLists.txt
index 8e7b46ab574..6e3ac1bd32f 100644
--- a/intern/cycles/kernel/CMakeLists.txt
+++ b/intern/cycles/kernel/CMakeLists.txt
@@ -50,7 +50,6 @@ set(SRC_KERNEL_DEVICE_GPU_HEADERS
   device/gpu/kernel.h
   device/gpu/parallel_active_index.h
   device/gpu/parallel_prefix_sum.h
-  device/gpu/parallel_reduce.h
   device/gpu/parallel_sorted_index.h
   device/gpu/work_stealing.h
 )
diff --git a/intern/cycles/kernel/device/cuda/compat.h b/intern/cycles/kernel/device/cuda/compat.h
index d7365e631aa..b392455c740 100644
--- a/intern/cycles/kernel/device/cuda/compat.h
+++ b/intern/cycles/kernel/device/cuda/compat.h
@@ -72,7 +72,6 @@ typedef unsigned long long uint64_t;
 
 #define ccl_gpu_syncthreads() __syncthreads()
 #define ccl_gpu_ballot(predicate) __ballot_sync(0xFFFFFFFF, predicate)
-#define ccl_gpu_shfl_down_sync(mask, var, detla) __shfl_down_sync(mask, var, detla)
 
 /* GPU texture objects */
 
diff --git a/intern/cycles/kernel/device/gpu/parallel_reduce.h b/intern/cycles/kernel/device/gpu/parallel_reduce.h
deleted file mode 100644
index 2b30dc9c666..00000000000
--- a/intern/cycles/kernel/device/gpu/parallel_reduce.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/* SPDX-License-Identifier: Apache-2.0
- * Copyright 2021-2022 Blender Foundation */
-
-#pragma once
-
-CCL_NAMESPACE_BEGIN
-
-/* Parallel sum of array input_data with size n into output_sum.
- *
- * Adapted from "Optimizing Parallel Reduction in GPU", Mark Harris.
- *
- * This version adds multiple elements per thread sequentially.  This reduces
- * the overall cost of the algorithm while keeping the work complexity O(n) and
- * the step complexity O(log n). (Brent's Theorem optimization) */
-
-#ifdef __HIP__
-#  define GPU_PARALLEL_SUM_DEFAULT_BLOCK_SIZE 1024
-#else
-#  define GPU_PARALLEL_SUM_DEFAULT_BLOCK_SIZE 512
-#endif
-
-template<uint blocksize, typename InputT, typename OutputT, typename ConvertOp>
-__device__ void gpu_parallel_sum(
-    const InputT *input_data, const uint n, OutputT *output_sum, OutputT zero, ConvertOp convert)
-{
-  extern ccl_gpu_shared OutputT shared_data[];
-
-  const uint tid = ccl_gpu_thread_idx_x;
-  const uint gridsize = blocksize * ccl_gpu_grid_dim_x();
-
-  OutputT sum = zero;
-  for (uint i = ccl_gpu_block_idx_x * blocksize + tid; i < n; i += gridsize) {
-    sum += convert(input_data[i]);
-  }
-  shared_data[tid] = sum;
-
-  ccl_gpu_syncthreads();
-
-  if (blocksize >= 512 && tid < 256) {
-    shared_data[tid] = sum = sum + shared_data[tid + 256];
-  }
-
-  ccl_gpu_syncthreads();
-
-  if (blocksize >= 256 && tid < 128) {
-    shared_data[tid] = sum = sum + shared_data[tid + 128];
-  }
-
-  ccl_gpu_syncthreads();
-
-  if (blocksize >= 128 && tid < 64) {
-    shared_data[tid] = sum = sum + shared_data[tid + 64];
-  }
-
-  ccl_gpu_syncthreads();
-
-  if (blocksize >= 64 && tid < 32) {
-    shared_data[tid] = sum = sum + shared_data[tid + 32];
-  }
-
-  ccl_gpu_syncthreads();
-
-  if (tid < 32) {
-    for (int offset = ccl_gpu_warp_size / 2; offset > 0; offset /= 2) {
-      sum += ccl_shfl_down_sync(0xFFFFFFFF, sum, offset);
-    }
-  }
-
-  if (tid == 0) {
-    output_sum[ccl_gpu_block_idx_x] = sum;
-  }
-}
-
-CCL_NAMESPACE_END
diff --git a/intern/cycles/kernel/device/hip/compat.h b/intern/cycles/kernel/device/hip/compat.h
index 6e117b84337..94d9d1273e8 100644
--- a/intern/cycles/kernel/device/hip/compat.h
+++ b/intern/cycles/kernel/device/hip/compat.h
@@ -71,7 +71,6 @@ typedef unsigned long long uint64_t;
 
 #define ccl_gpu_syncthreads() __syncthreads()
 #define ccl_gpu_ballot(predicate) __ballot(predicate)
-#define ccl_gpu_shfl_down_sync(mask, var, detla) __shfl_down(var, detla)
 
 /* GPU texture objects */
 typedef hipTextureObject_t ccl_gpu_tex_object;
diff --git a/intern/cycles/kernel/device/optix/compat.h b/intern/cycles/kernel/device/optix/compat.h
index e7fe7139cc1..ae7a0309e51 100644
--- a/intern/cycles/kernel/device/optix/compat.h
+++ b/intern/cycles/kernel/device/optix/compat.h
@@ -74,7 +74,6 @@ typedef unsigned long long uint64_t;
 
 #define ccl_gpu_syncthreads() __syncthreads()
 #define ccl_gpu_ballot(predicate) __ballot_sync(0xFFFFFFFF, predicate)
-#define ccl_gpu_shfl_down_sync(mask, var, detla) __shfl_down_sync(mask, var, detla)
 
 /* GPU texture objects */