Refactor: use 'BLI_task_parallel_range' in Draw Cache

One drawback to trying to predict the number of threads that will be
used in the `task_graph` is that we are only sure of the number when the
threads are running.

Using `BLI_task_parallel_range` allows the driver to
choose the best thread distribution through `parallel_reduce`.

The benefit is most evident on hardware with fewer cores.

This is the result on an 4-core laptop:
||before:|after:
|---|---|---|
|large_mesh_editing:|Average: 5.203638 FPS|Average: 5.398925 FPS
||rdata 15ms iter 43ms (frame 193ms)|rdata 14ms iter 36ms (frame 187ms)

Differential Revision: https://developer.blender.org/D11558

1 files changed, 1 insertions, 2 deletions

diff --git a/source/blender/gpu/GPU_index_buffer.h b/source/blender/gpu/GPU_index_buffer.h
index 48f80e321b6..a89ed91674f 100644
--- a/source/blender/gpu/GPU_index_buffer.h
+++ b/source/blender/gpu/GPU_index_buffer.h
@@ -58,8 +58,7 @@ GPUIndexBuf *GPU_indexbuf_build_on_device(uint index_len);
  *
  * Function inspired by the reduction directives of multithread work APIs..
  */
-void GPU_indexbuf_join_copies(GPUIndexBufBuilder *builder,
-                              const GPUIndexBufBuilder *parent_builder);
+void GPU_indexbuf_join(GPUIndexBufBuilder *builder, const GPUIndexBufBuilder *parent_builder);
 
 void GPU_indexbuf_add_generic_vert(GPUIndexBufBuilder *, uint v);
 void GPU_indexbuf_add_primitive_restart(GPUIndexBufBuilder *);