[Mesa-dev] [PATCH 1/2] nir: add an option for skipping split_alu_of_phi
Samuel Pitoiset
samuel.pitoiset at gmail.com
Tue Apr 23 15:45:50 UTC 2019
On 4/23/19 5:16 PM, Jason Ekstrand wrote:
> On Tue, Apr 23, 2019 at 7:46 AM Samuel Pitoiset
> <samuel.pitoiset at gmail.com <mailto:samuel.pitoiset at gmail.com>> wrote:
>
>
> On 4/23/19 10:45 AM, Bas Nieuwenhuizen wrote:
> > On Tue, Apr 23, 2019 at 9:35 AM Samuel Pitoiset
> > <samuel.pitoiset at gmail.com <mailto:samuel.pitoiset at gmail.com>>
> wrote:
> >> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com
> <mailto:samuel.pitoiset at gmail.com>>
> >> ---
> >> src/amd/vulkan/radv_shader.c | 2 +-
> >> src/compiler/nir/nir.h | 3 ++-
> >> src/compiler/nir/nir_opt_if.c | 17
> ++++++++++-------
> >> src/freedreno/ir3/ir3_nir.c | 2 +-
> >> src/gallium/auxiliary/nir/tgsi_to_nir.c | 2 +-
> >> src/gallium/drivers/freedreno/a2xx/ir2_nir.c | 2 +-
> >> src/gallium/drivers/radeonsi/si_shader_nir.c | 2 +-
> >> src/intel/compiler/brw_nir.c | 2 +-
> >> src/mesa/state_tracker/st_glsl_to_nir.cpp | 2 +-
> >> 9 files changed, 19 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/src/amd/vulkan/radv_shader.c
> b/src/amd/vulkan/radv_shader.c
> >> index 13f1f9aa9dc..54a4e732230 100644
> >> --- a/src/amd/vulkan/radv_shader.c
> >> +++ b/src/amd/vulkan/radv_shader.c
> >> @@ -158,7 +158,7 @@ radv_optimize_nir(struct nir_shader
> *shader, bool optimize_conservatively,
> >> NIR_PASS(progress, shader,
> nir_opt_remove_phis);
> >> NIR_PASS(progress, shader, nir_opt_dce);
> >> }
> >> - NIR_PASS(progress, shader, nir_opt_if, true);
> >> + NIR_PASS(progress, shader, nir_opt_if, true,
> false);
> >> NIR_PASS(progress, shader, nir_opt_dead_cf);
> >> NIR_PASS(progress, shader, nir_opt_cse);
> >> NIR_PASS(progress, shader,
> nir_opt_peephole_select, 8, true, true);
> >> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> >> index 7d2062d3691..d7506d6ddd1 100644
> >> --- a/src/compiler/nir/nir.h
> >> +++ b/src/compiler/nir/nir.h
> >> @@ -3474,7 +3474,8 @@ bool nir_opt_gcm(nir_shader *shader, bool
> value_number);
> >>
> >> bool nir_opt_idiv_const(nir_shader *shader, unsigned
> min_bit_size);
> >>
> >> -bool nir_opt_if(nir_shader *shader, bool
> aggressive_last_continue);
> >> +bool nir_opt_if(nir_shader *shader, bool aggressive_last_continue,
> >> + bool skip_alu_of_phi);
> > Can we have a flag for this instead (e.g. something like
> > nir_opt_if_skip_alu_of_phi)? I think have a function with a bunch of
> > bools is less than ideal as you can't see at the calling site
> what is
> > for what arg.
> Yes, that seems better to me.
>
>
> This is the worst kind of hack all around. We're making NIR more
> complicated and adding a flag to disable a useful and correct piece of
> an optimization, not because it causes a perf regression but because
> the back-end compiler is broken and this is easier than fixing it
> properly. Seriously? Can't we just fix the LLVM back-end? Or, if
> this optimization is actually doing something wrong, fix it? Or maybe
> actually figure out what pattern is causing LLVM to fall over and have
> a hack in your NIR -> LLVM pass? On the list of "good ways to fix
> this problem", this seems to be pretty far down if it hasn't fallen
> off the bottom.
Best hack of the month? :-)
As discussed over IRC, this is definitely not the best solution, I don't
like it either as I said.
I will work on a different solution maybe in our NIR->LLVM pass.
The aggressive_last_continue option should also be removed (make it
default?).
>
> --Jason
>
> >> bool nir_opt_intrinsics(nir_shader *shader);
> >>
> >> diff --git a/src/compiler/nir/nir_opt_if.c
> b/src/compiler/nir/nir_opt_if.c
> >> index f674185f1e2..149b3bd1659 100644
> >> --- a/src/compiler/nir/nir_opt_if.c
> >> +++ b/src/compiler/nir/nir_opt_if.c
> >> @@ -1385,7 +1385,8 @@ opt_if_cf_list(nir_builder *b, struct
> exec_list *cf_list,
> >> * not do anything to cause the metadata to become invalid.
> >> */
> >> static bool
> >> -opt_if_safe_cf_list(nir_builder *b, struct exec_list *cf_list)
> >> +opt_if_safe_cf_list(nir_builder *b, struct exec_list *cf_list,
> >> + bool skip_alu_of_phi)
> >> {
> >> bool progress = false;
> >> foreach_list_typed(nir_cf_node, cf_node, node, cf_list) {
> >> @@ -1395,16 +1396,17 @@ opt_if_safe_cf_list(nir_builder *b,
> struct exec_list *cf_list)
> >>
> >> case nir_cf_node_if: {
> >> nir_if *nif = nir_cf_node_as_if(cf_node);
> >> - progress |= opt_if_safe_cf_list(b, &nif->then_list);
> >> - progress |= opt_if_safe_cf_list(b, &nif->else_list);
> >> + progress |= opt_if_safe_cf_list(b, &nif->then_list,
> skip_alu_of_phi);
> >> + progress |= opt_if_safe_cf_list(b, &nif->else_list,
> skip_alu_of_phi);
> >> progress |= opt_if_evaluate_condition_use(b, nif);
> >> break;
> >> }
> >>
> >> case nir_cf_node_loop: {
> >> nir_loop *loop = nir_cf_node_as_loop(cf_node);
> >> - progress |= opt_if_safe_cf_list(b, &loop->body);
> >> - progress |= opt_split_alu_of_phi(b, loop);
> >> + progress |= opt_if_safe_cf_list(b, &loop->body,
> skip_alu_of_phi);
> >> + if (!skip_alu_of_phi)
> >> + progress |= opt_split_alu_of_phi(b, loop);
> >> break;
> >> }
> >>
> >> @@ -1417,7 +1419,8 @@ opt_if_safe_cf_list(nir_builder *b,
> struct exec_list *cf_list)
> >> }
> >>
> >> bool
> >> -nir_opt_if(nir_shader *shader, bool aggressive_last_continue)
> >> +nir_opt_if(nir_shader *shader, bool aggressive_last_continue,
> >> + bool skip_alu_of_phi)
> >> {
> >> bool progress = false;
> >>
> >> @@ -1430,7 +1433,7 @@ nir_opt_if(nir_shader *shader, bool
> aggressive_last_continue)
> >>
> >> nir_metadata_require(function->impl,
> nir_metadata_block_index |
> >> nir_metadata_dominance);
> >> - progress = opt_if_safe_cf_list(&b, &function->impl->body);
> >> + progress = opt_if_safe_cf_list(&b,
> &function->impl->body, skip_alu_of_phi);
> >> nir_metadata_preserve(function->impl,
> nir_metadata_block_index |
> >> nir_metadata_dominance);
> >>
> >> diff --git a/src/freedreno/ir3/ir3_nir.c
> b/src/freedreno/ir3/ir3_nir.c
> >> index 76230e3be50..1bec3c030a9 100644
> >> --- a/src/freedreno/ir3/ir3_nir.c
> >> +++ b/src/freedreno/ir3/ir3_nir.c
> >> @@ -147,7 +147,7 @@ ir3_optimize_loop(nir_shader *s)
> >> OPT(s, nir_copy_prop);
> >> OPT(s, nir_opt_dce);
> >> }
> >> - progress |= OPT(s, nir_opt_if, false);
> >> + progress |= OPT(s, nir_opt_if, false, false);
> >> progress |= OPT(s, nir_opt_remove_phis);
> >> progress |= OPT(s, nir_opt_undef);
> >>
> >> diff --git a/src/gallium/auxiliary/nir/tgsi_to_nir.c
> b/src/gallium/auxiliary/nir/tgsi_to_nir.c
> >> index c55e8b84a41..6b40bff1f73 100644
> >> --- a/src/gallium/auxiliary/nir/tgsi_to_nir.c
> >> +++ b/src/gallium/auxiliary/nir/tgsi_to_nir.c
> >> @@ -2066,7 +2066,7 @@ ttn_optimize_nir(nir_shader *nir, bool
> scalar)
> >> NIR_PASS(progress, nir, nir_opt_dce);
> >> }
> >>
> >> - NIR_PASS(progress, nir, nir_opt_if, false);
> >> + NIR_PASS(progress, nir, nir_opt_if, false, false);
> >> NIR_PASS(progress, nir, nir_opt_dead_cf);
> >> NIR_PASS(progress, nir, nir_opt_cse);
> >> NIR_PASS(progress, nir, nir_opt_peephole_select, 8,
> true, true);
> >> diff --git a/src/gallium/drivers/freedreno/a2xx/ir2_nir.c
> b/src/gallium/drivers/freedreno/a2xx/ir2_nir.c
> >> index ee348ca6a93..3522971e435 100644
> >> --- a/src/gallium/drivers/freedreno/a2xx/ir2_nir.c
> >> +++ b/src/gallium/drivers/freedreno/a2xx/ir2_nir.c
> >> @@ -94,7 +94,7 @@ ir2_optimize_loop(nir_shader *s)
> >> OPT(s, nir_opt_dce);
> >> }
> >> progress |= OPT(s, nir_opt_loop_unroll,
> nir_var_all);
> >> - progress |= OPT(s, nir_opt_if, false);
> >> + progress |= OPT(s, nir_opt_if, false, false);
> >> progress |= OPT(s, nir_opt_remove_phis);
> >> progress |= OPT(s, nir_opt_undef);
> >>
> >> diff --git a/src/gallium/drivers/radeonsi/si_shader_nir.c
> b/src/gallium/drivers/radeonsi/si_shader_nir.c
> >> index 5a925f19e09..7f1fe4ba2e9 100644
> >> --- a/src/gallium/drivers/radeonsi/si_shader_nir.c
> >> +++ b/src/gallium/drivers/radeonsi/si_shader_nir.c
> >> @@ -879,7 +879,7 @@ si_lower_nir(struct si_shader_selector* sel)
> >> NIR_PASS(progress, sel->nir,
> nir_copy_prop);
> >> NIR_PASS(progress, sel->nir, nir_opt_dce);
> >> }
> >> - NIR_PASS(progress, sel->nir, nir_opt_if, true);
> >> + NIR_PASS(progress, sel->nir, nir_opt_if, true,
> false);
> >> NIR_PASS(progress, sel->nir, nir_opt_dead_cf);
> >> NIR_PASS(progress, sel->nir, nir_opt_cse);
> >> NIR_PASS(progress, sel->nir,
> nir_opt_peephole_select, 8, true, true);
> >> diff --git a/src/intel/compiler/brw_nir.c
> b/src/intel/compiler/brw_nir.c
> >> index e0a393fc298..ba911049ce3 100644
> >> --- a/src/intel/compiler/brw_nir.c
> >> +++ b/src/intel/compiler/brw_nir.c
> >> @@ -607,7 +607,7 @@ brw_nir_optimize(nir_shader *nir, const
> struct brw_compiler *compiler,
> >> OPT(nir_copy_prop);
> >> OPT(nir_opt_dce);
> >> }
> >> - OPT(nir_opt_if, false);
> >> + OPT(nir_opt_if, false, false);
> >> if (nir->options->max_unroll_iterations != 0) {
> >> OPT(nir_opt_loop_unroll, indirect_mask);
> >> }
> >> diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp
> b/src/mesa/state_tracker/st_glsl_to_nir.cpp
> >> index 97b2831b880..3f1f78e875b 100644
> >> --- a/src/mesa/state_tracker/st_glsl_to_nir.cpp
> >> +++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp
> >> @@ -324,7 +324,7 @@ st_nir_opts(nir_shader *nir, bool scalar)
> >> NIR_PASS(progress, nir, nir_copy_prop);
> >> NIR_PASS(progress, nir, nir_opt_dce);
> >> }
> >> - NIR_PASS(progress, nir, nir_opt_if, false);
> >> + NIR_PASS(progress, nir, nir_opt_if, false, false);
> >> NIR_PASS(progress, nir, nir_opt_dead_cf);
> >> NIR_PASS(progress, nir, nir_opt_cse);
> >> NIR_PASS(progress, nir, nir_opt_peephole_select, 8,
> true, true);
> >> --
> >> 2.21.0
> >>
> >> _______________________________________________
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> >> mesa-dev at lists.freedesktop.org
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