I had noticed the code to remove dead deref's in a few of the passes (at least on your wip branch), and had wondered a bit about not just requiring all the deref related lowering to happen in ssa and possibly require dce after, although admittedly hadn't thought about it *too* much yet..
I kinda expected to use the dce clean things up once we are in a deref-instruction world.. re: validation passes, could we not just allow dead deref instructions to be ok. That seems like kind of a natural thing.. BR, -R On Wed, Mar 28, 2018 at 7:43 PM, Jason Ekstrand <ja...@jlekstrand.net> wrote: > One interesting and unexpected side effect of this series has been that dead > code elimination is now required to clean up unused deref instructions. > This can be a problem for passes which alter and/or delete the variable > because they may leave invalid deref instructions lying around. This is a > bit troublesome because it causes validation issues and can confused later > passes if there are invalid deref instructions even if they are unused. I > have added a helper that allows you to easily check if a deref instruction > is in use and remove it and its ancestors if it is not. This seems to help a > bit but means that you have to manually clean up derefs whenever you alter > or remove a variable. Another option would be to write a simple dead deref > elimination pass that other optimization passes can run. > > I'm not 100% sure what I think of that. On the balance, though, I think the > amount that removing deref chains simplifies the IR still makes it worth it. > > > On March 23, 2018 14:43:16 Jason Ekstrand <ja...@jlekstrand.net> wrote: > >> This is something that Connor and I have been talking about for some time >> now. The basic idea is to replace the current singly linked nir_deref >> list >> with deref instructions. This is similar to what LLVM does and it offers >> quite a bit more freedom when we start getting more realistic pointers >> from >> compute applications. >> >> This series implements an almost complete conversion for both i965 and >> anv. >> The two remaining gaps are nir_lower_locals_to_regs and >> nir_lower_samplers. >> The former will have to wait for ir3 to be converted and the later will >> have to wait for radeonsi. I've got patches for nir_lower_samplers but >> not >> nir_lower_samplers_as_deref which is required by at least radeonsi. Once >> those are in place, we should be able to drop the lowering pass from the >> Intel back-end completely. >> >> The next step (which I will start on next week) will be removing legacy >> derefs from core NIR. This will also involve significant reworks in some >> passes such as vars_to_ssa which still uses legacy derefs internally even >> for things which use deref instructions. >> >> Clearly, we can't remove anything until all of the other drivers are >> converted. However, this series should be a good basis for anyone wanting >> to work on converting another driver since almost all of the core NIR >> passes now work with both types of derefs so you can convert in whatever >> way makes sense. >> >> This series can be found as a branch on gitlab: >> >> >> https://gitlab.freedesktop.org/jekstrand/mesa/commits/review/nir-deref-instrs-v1 >> >> Cc: Rob Clark <robdcl...@gmail.com> >> Cc: Timothy Arceri <tarc...@itsqueeze.com> >> Cc: Eric Anholt <e...@anholt.net> >> Cc: Connor Abbott <cwabbo...@gmail.com> >> Cc: Bas Nieuwenhuizen <b...@basnieuwenhuizen.nl> >> Cc: Karol Herbst <kher...@redhat.com> >> >> Jason Ekstrand (61): >> nir: Add src/dest num_components helpers >> nir: Return a cursor from nir_instr_remove >> nir/vars_to_ssa: Remove copies from the correct set >> nir/lower_indirect_derefs: Support interp_var_at intrinsics >> intel/vec4: Set channel_sizes for MOV_INDIRECT sources >> nir/validator: Validate that all used variables exist >> nir: Add a deref instruction type >> nir/builder: Add deref building helpers >> nir: Add _deref versions of all of the _var intrinsics >> nir: Add deref sources to texture instructions >> nir: Add helpers for working with deref instructions >> anv,i965,radv,st,ir3: Call nir_lower_deref_instrs >> glsl/nir: Only claim to handle intrinsic functions >> glsl/nir: Use deref instructions instead of dref chains >> prog/nir: Simplify some load/store operations >> prog/nir: Use deref instructions for params >> nir/lower_atomics: Rework the main walker loop a bit >> nir: Support deref instructions in remove_dead_variables >> nir: Add a pass for fixing deref modes >> nir: Support deref instructions in lower_global_vars_to_local >> nir: Support deref instructions in lower_io_to_temporaries >> nir: Add a deref path helper struct >> nir: Support deref instructions in lower_var_copies >> nir: Support deref instructions in split_var_copies >> nir: Support deref instructions in lower_vars_to_ssa >> nir: Support deref instructions in lower_indirect_derefs >> nir/deref: Add a deref cleanup function >> nir: Support deref instructions in lower_system_values >> nir: Support deref instructions in lower_clip_cull >> nir: Support deref instructions in propagate_invariant >> nir: Support deref instructions in gather_info >> nir: Support deref instructions in lower_io >> nir: Support deref instructions in lower_atomics >> nir: Support deref instructions in lower_wpos_ytransform >> nir: Support deref instructions in lower_pos_center >> nir: Support deref instructions in remove_unused_varyings >> intel,ir3: Disable nir_opt_copy_prop_vars >> intel/nir: Fixup deref modes after lowering patch vertices >> i965: Move nir_lower_deref_instrs to right before locals_to_regs >> st/nir: Move lower_deref_instrs later >> spirv: Use deref instructions for most variables >> nir: Add a concept of per-member structs and a lowering pass >> nir/lower_system_values: Support SYSTEM_VALUE_LOCAL_GROUP_SIZE >> spirv: Use the LOCAL_GROUP_SIZE system value >> nir/spirv: Pass nir_variable_data into apply_var_decoration >> anv/pipeline: Lower more constant initializers earlier >> spirv: Use NIR per-member splitting >> spirv: Make push constants an offset-based pointer >> spirv: Clean up vtn_pointer_to_offset >> spirv: Allow pointers to have a deref at the base >> spirv: Update vtn_pointer_to/from_ssa to handle deref pointers >> spirv: Record the type of functions >> spirv/cfg: Make the builder fully capable for both walks >> nir,spirv: Rework function calls >> anv/pipeline: Do less deref instruction lowering >> anv/pipeline: Convert lower_input_attachments to deref instructions >> anv/pipeline: Convert YCbCr lowering to deref instructiosn >> anv/apply_pipeline_layout: Simplify extract_tex_src_plane >> anv/pipeline: Convert apply_pipeline_layout to deref instructions >> intel/fs: Use image_deref intrinsics instead of image_var >> intel/nir: Only lower load/store derefs >> >> src/amd/vulkan/radv_shader.c | 10 + >> src/compiler/Makefile.sources | 3 + >> src/compiler/glsl/glsl_to_nir.cpp | 265 ++++------ >> src/compiler/nir/meson.build | 3 + >> src/compiler/nir/nir.c | 107 ++-- >> src/compiler/nir/nir.h | 175 +++++- >> src/compiler/nir/nir_builder.h | 236 +++++++++ >> src/compiler/nir/nir_clone.c | 65 ++- >> src/compiler/nir/nir_deref.c | 393 ++++++++++++++ >> src/compiler/nir/nir_deref.h | 55 ++ >> src/compiler/nir/nir_gather_info.c | 26 +- >> src/compiler/nir/nir_inline_functions.c | 193 +------ >> src/compiler/nir/nir_instr_set.c | 78 +++ >> src/compiler/nir/nir_intrinsics.h | 88 ++++ >> src/compiler/nir/nir_linking_helpers.c | 50 +- >> src/compiler/nir/nir_lower_atomics.c | 137 ++++- >> .../nir/nir_lower_clip_cull_distance_arrays.c | 69 ++- >> src/compiler/nir/nir_lower_global_vars_to_local.c | 62 ++- >> src/compiler/nir/nir_lower_indirect_derefs.c | 169 +++++- >> src/compiler/nir/nir_lower_io.c | 70 ++- >> src/compiler/nir/nir_lower_io_to_temporaries.c | 2 + >> src/compiler/nir/nir_lower_system_values.c | 23 +- >> src/compiler/nir/nir_lower_var_copies.c | 90 +++- >> src/compiler/nir/nir_lower_vars_to_ssa.c | 77 ++- >> src/compiler/nir/nir_lower_wpos_center.c | 13 +- >> src/compiler/nir/nir_lower_wpos_ytransform.c | 51 +- >> src/compiler/nir/nir_opt_copy_prop_vars.c | 19 +- >> src/compiler/nir/nir_opt_copy_propagate.c | 62 ++- >> src/compiler/nir/nir_opt_dce.c | 7 + >> src/compiler/nir/nir_print.c | 119 +++-- >> src/compiler/nir/nir_propagate_invariant.c | 23 +- >> src/compiler/nir/nir_remove_dead_variables.c | 117 +++- >> src/compiler/nir/nir_serialize.c | 137 +++-- >> src/compiler/nir/nir_split_per_member_structs.c | 289 ++++++++++ >> src/compiler/nir/nir_split_var_copies.c | 42 ++ >> src/compiler/nir/nir_sweep.c | 4 - >> src/compiler/nir/nir_validate.c | 143 +++-- >> src/compiler/spirv/spirv_to_nir.c | 180 ++++--- >> src/compiler/spirv/vtn_cfg.c | 231 ++++---- >> src/compiler/spirv/vtn_glsl450.c | 19 +- >> src/compiler/spirv/vtn_private.h | 28 +- >> src/compiler/spirv/vtn_variables.c | 586 >> +++++++-------------- >> src/gallium/drivers/freedreno/ir3/ir3_cmdline.c | 3 + >> src/gallium/drivers/freedreno/ir3/ir3_nir.c | 2 +- >> src/intel/compiler/brw_fs.h | 2 +- >> src/intel/compiler/brw_fs_nir.cpp | 157 +++--- >> src/intel/compiler/brw_nir.c | 4 +- >> src/intel/compiler/brw_vec4.cpp | 5 +- >> src/intel/vulkan/anv_nir_apply_pipeline_layout.c | 187 +++---- >> src/intel/vulkan/anv_nir_lower_input_attachments.c | 31 +- >> src/intel/vulkan/anv_nir_lower_ycbcr_textures.c | 34 +- >> src/intel/vulkan/anv_pipeline.c | 19 +- >> src/mesa/drivers/dri/i965/brw_nir_uniforms.cpp | 2 + >> src/mesa/drivers/dri/i965/brw_program.c | 1 + >> src/mesa/program/prog_to_nir.c | 65 +-- >> src/mesa/state_tracker/st_glsl_to_nir.cpp | 2 + >> 56 files changed, 3451 insertions(+), 1579 deletions(-) >> create mode 100644 src/compiler/nir/nir_deref.c >> create mode 100644 src/compiler/nir/nir_deref.h >> create mode 100644 src/compiler/nir/nir_split_per_member_structs.c >> >> -- >> 2.5.0.400.gff86faf > > > > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
