[Mesa-dev] [PATCH 1/2] nir: add an option for skipping split_alu_of_phi
Jason Ekstrand
jason at jlekstrand.net
Wed Apr 24 00:59:18 UTC 2019
On Tue, Apr 23, 2019 at 7:39 PM Timothy Arceri <tarceri at itsqueeze.com>
wrote:
> On 24/4/19 1:45 am, Samuel Pitoiset wrote:
> >
> > 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?).
>
> The aggressive_last_continue option is not a hack to avoid a bug in a
> driver backend it is to avoid perf regressions. That said we may be able
> to remove it now that Jason has landed
> cd4ffb376f2aeefdd6a1b80d69a1580c4e569778
>
I don't think anyone was claiming it was. The only claim made was that
it's probably an ultimately unnecessary option and we should try to apply
it universally.
--Jason
> >
> >>
> >> --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
> >> >>
> >> >> _______________________________________________
> >> >> mesa-dev mailing list
> >> >> mesa-dev at lists.freedesktop.org
> >> <mailto:mesa-dev at lists.freedesktop.org>
> >> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >> _______________________________________________
> >> mesa-dev mailing list
> >> mesa-dev at lists.freedesktop.org <mailto:
> mesa-dev at lists.freedesktop.org>
> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >>
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
>
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