[Mesa-dev] [PATCH] nir: Add a pass for lower indirect variable dereferences
Jason Ekstrand
jason at jlekstrand.net
Tue Mar 8 18:41:02 UTC 2016
On Wed, Feb 24, 2016 at 10:25 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:
> On Sat, Feb 13, 2016 at 8:48 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > This new pass lowers load/store_var intrinsics that act on indirect
> derefs
> > to if-ladder of direct load/store_var intrinsics. The if-ladders
> perform a
> > simple binary search on the indirect.
> > ---
> > src/compiler/Makefile.sources | 1 +
> > src/compiler/nir/Makefile.sources | 1 +
> > src/compiler/nir/nir.h | 2 +
> > src/compiler/nir/nir_lower_indirect_derefs.c | 239
> +++++++++++++++++++++++++++
> > 4 files changed, 243 insertions(+)
> > create mode 100644 src/compiler/nir/nir_lower_indirect_derefs.c
> >
> > diff --git a/src/compiler/Makefile.sources
> b/src/compiler/Makefile.sources
> > index c9780d6..9f3bcf0 100644
> > --- a/src/compiler/Makefile.sources
> > +++ b/src/compiler/Makefile.sources
> > @@ -189,6 +189,7 @@ NIR_FILES = \
> > nir/nir_lower_load_const_to_scalar.c \
> > nir/nir_lower_locals_to_regs.c \
> > nir/nir_lower_idiv.c \
> > + nir/nir_lower_indirect_derefs.c \
> > nir/nir_lower_io.c \
> > nir/nir_lower_outputs_to_temporaries.c \
> > nir/nir_lower_phis_to_scalar.c \
> > diff --git a/src/compiler/nir/Makefile.sources
> b/src/compiler/nir/Makefile.sources
> > index 0755a10..f31547b 100644
> > --- a/src/compiler/nir/Makefile.sources
> > +++ b/src/compiler/nir/Makefile.sources
> > @@ -33,6 +33,7 @@ NIR_FILES = \
> > nir_lower_load_const_to_scalar.c \
> > nir_lower_locals_to_regs.c \
> > nir_lower_idiv.c \
> > + nir_lower_indirect_derefs.c \
> > nir_lower_io.c \
> > nir_lower_outputs_to_temporaries.c \
> > nir_lower_phis_to_scalar.c \
> > diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> > index cccb3a4..cfbac81 100644
> > --- a/src/compiler/nir/nir.h
> > +++ b/src/compiler/nir/nir.h
> > @@ -2055,6 +2055,8 @@ void nir_lower_var_copies(nir_shader *shader);
> >
> > bool nir_lower_global_vars_to_local(nir_shader *shader);
> >
> > +bool nir_lower_indirect_derefs(nir_shader *shader, uint32_t mode_mask);
> > +
> > bool nir_lower_locals_to_regs(nir_shader *shader);
> >
> > void nir_lower_outputs_to_temporaries(nir_shader *shader);
> > diff --git a/src/compiler/nir/nir_lower_indirect_derefs.c
> b/src/compiler/nir/nir_lower_indirect_derefs.c
> > new file mode 100644
> > index 0000000..69f2df4
> > --- /dev/null
> > +++ b/src/compiler/nir/nir_lower_indirect_derefs.c
> > @@ -0,0 +1,239 @@
> > +/*
> > + * Copyright © 2016 Intel Corporation
> > + *
> > + * Permission is hereby granted, free of charge, to any person
> obtaining a
> > + * copy of this software and associated documentation files (the
> "Software"),
> > + * to deal in the Software without restriction, including without
> limitation
> > + * the rights to use, copy, modify, merge, publish, distribute,
> sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the
> next
> > + * paragraph) shall be included in all copies or substantial portions
> of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> > + * IN THE SOFTWARE.
> > + */
> > +
> > +#include "nir.h"
> > +#include "nir_builder.h"
> > +
> > +static void
> > +emit_load_store(nir_builder *b, nir_intrinsic_instr *orig_instr,
> > + nir_deref_var *deref, nir_deref *tail,
> > + nir_ssa_def **dest, nir_ssa_def *src);
> > +
> > +static void
> > +emit_indirect_load_store(nir_builder *b, nir_intrinsic_instr
> *orig_instr,
> > + nir_deref_var *deref, nir_deref *arr_parent,
> > + int start, int end,
> > + nir_ssa_def **dest, nir_ssa_def *src)
> > +{
> > + assert(arr_parent->child &&
> > + arr_parent->child->deref_type == nir_deref_type_array);
> > + nir_deref_array *arr = nir_deref_as_array(arr_parent->child);
> > + assert(arr->deref_array_type == nir_deref_array_type_indirect);
> > + assert(arr->indirect.is_ssa);
> > +
> > + assert(start < end);
> > + if (start == end - 1) {
> > + /* Base case. Just emit the load/store op */
> > + nir_deref_array direct = *arr;
> > + direct.deref_array_type = nir_deref_array_type_direct;
> > + direct.base_offset += start;
> > + direct.indirect = NIR_SRC_INIT;
> > +
> > + arr_parent->child = &direct.deref;
> > + emit_load_store(b, orig_instr, deref, &arr->deref, dest, src);
> > + arr_parent->child = &arr->deref;
> > + } else {
> > + int mid = start + (end - start) / 2;
> > +
> > + nir_ssa_def *then_dest, *else_dest;
> > +
> > + nir_if *if_stmt = nir_if_create(b->shader);
> > + if_stmt->condition = nir_src_for_ssa(nir_ilt(b, arr->indirect.ssa,
> > + nir_imm_int(b,
> mid)));
> > + nir_cf_node_insert(b->cursor, &if_stmt->cf_node);
> > +
> > + b->cursor = nir_after_cf_list(&if_stmt->then_list);
> > + emit_indirect_load_store(b, orig_instr, deref, arr_parent,
> > + start, mid, &then_dest, src);
> > +
> > + b->cursor = nir_after_cf_list(&if_stmt->else_list);
> > + emit_indirect_load_store(b, orig_instr, deref, arr_parent,
> > + mid, end, &else_dest, src);
> > +
> > + b->cursor = nir_after_cf_node(&if_stmt->cf_node);
> > +
> > + if (src == NULL) {
> > + /* We're a load. We need to insert a phi node */
> > + nir_phi_instr *phi = nir_phi_instr_create(b->shader);
> > + nir_ssa_dest_init(&phi->instr, &phi->dest,
> > + then_dest->num_components, NULL);
> > +
> > + nir_phi_src *src0 = ralloc(phi, nir_phi_src);
> > + src0->pred =
> nir_cf_node_as_block(nir_if_last_then_node(if_stmt));
> > + src0->src = nir_src_for_ssa(then_dest);
> > + exec_list_push_tail(&phi->srcs, &src0->node);
> > +
> > + nir_phi_src *src1 = ralloc(phi, nir_phi_src);
> > + src1->pred =
> nir_cf_node_as_block(nir_if_last_else_node(if_stmt));
> > + src1->src = nir_src_for_ssa(else_dest);
> > + exec_list_push_tail(&phi->srcs, &src1->node);
> > +
> > + nir_builder_instr_insert(b, &phi->instr);
> > + *dest = &phi->dest.ssa;
> > + }
> > + }
> > +}
> > +
> > +static void
> > +emit_load_store(nir_builder *b, nir_intrinsic_instr *orig_instr,
> > + nir_deref_var *deref, nir_deref *tail,
> > + nir_ssa_def **dest, nir_ssa_def *src)
> > +{
> > + for (; tail->child; tail = tail->child) {
> > + if (tail->child->deref_type != nir_deref_type_array)
> > + continue;
> > +
> > + nir_deref_array *arr = nir_deref_as_array(tail->child);
> > + if (arr->deref_array_type != nir_deref_array_type_indirect)
> > + continue;
> > +
> > + int length = glsl_get_length(tail->type);
> > +
> > + emit_indirect_load_store(b, orig_instr, deref, tail,
> -arr->base_offset,
> > + length - arr->base_offset, dest, src);
> > + return;
> > + }
> > +
> > + assert(tail && tail->child == NULL);
> > +
> > + /* We reached the end of the deref chain. Emit the instruction */
> > +
> > + if (src == NULL) {
> > + /* This is a load instruction */
> > + nir_intrinsic_instr *load =
> > + nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_var);
> > + load->num_components = orig_instr->num_components;
> > + load->variables[0] =
> > + nir_deref_as_var(nir_copy_deref(load, &deref->deref));
> > + nir_ssa_dest_init(&load->instr, &load->dest,
> > + load->num_components, NULL);
> > + nir_builder_instr_insert(b, &load->instr);
> > + *dest = &load->dest.ssa;
> > + } else {
> > + /* This is a store instruction */
> > + nir_intrinsic_instr *store =
> > + nir_intrinsic_instr_create(b->shader, nir_intrinsic_store_var);
> > + store->num_components = orig_instr->num_components;
> > + store->const_index[0] = orig_instr->const_index[0]; /* writemask
> */
>
> This should probably use Rob's new setters/getters to make it more
> readable/robust. Other than that, this patch is
>
Done
> Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
>
Thanks!
>
> > + store->variables[0] =
> > + nir_deref_as_var(nir_copy_deref(store, &deref->deref));
> > + store->src[0] = nir_src_for_ssa(src);
> > + nir_builder_instr_insert(b, &store->instr);
> > + }
> > +}
> > +
> > +static bool
> > +deref_has_indirect(nir_deref_var *deref)
> > +{
> > + for (nir_deref *tail = deref->deref.child; tail; tail = tail->child)
> {
> > + if (tail->deref_type != nir_deref_type_array)
> > + continue;
> > +
> > + nir_deref_array *arr = nir_deref_as_array(tail);
> > + if (arr->deref_array_type == nir_deref_array_type_indirect)
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > +struct lower_indirect_state {
> > + nir_builder builder;
> > + uint32_t mode_mask;
> > + bool progress;
> > +};
> > +
> > +static bool
> > +lower_indirect_block(nir_block *block, void *void_state)
> > +{
> > + struct lower_indirect_state *state = void_state;
> > +
> > + nir_foreach_instr_safe(block, instr) {
> > + if (instr->type != nir_instr_type_intrinsic)
> > + continue;
> > +
> > + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
> > + if (intrin->intrinsic != nir_intrinsic_load_var &&
> > + intrin->intrinsic != nir_intrinsic_store_var)
> > + continue;
> > +
> > + if (!deref_has_indirect(intrin->variables[0]))
> > + continue;
> > +
> > + /* Only lower variables whose mode is in the mask */
> > + if (!(state->mode_mask & (1 <<
> intrin->variables[0]->var->data.mode)))
> > + continue;
> > +
> > + state->builder.cursor = nir_before_instr(&intrin->instr);
> > +
> > + if (intrin->intrinsic == nir_intrinsic_load_var) {
> > + nir_ssa_def *result;
> > + emit_load_store(&state->builder, intrin, intrin->variables[0],
> > + &intrin->variables[0]->deref, &result, NULL);
> > + nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
> nir_src_for_ssa(result));
> > + } else {
> > + assert(intrin->src[0].is_ssa);
> > + emit_load_store(&state->builder, intrin, intrin->variables[0],
> > + &intrin->variables[0]->deref, NULL,
> intrin->src[0].ssa);
> > + }
> > + nir_instr_remove(&intrin->instr);
> > + state->progress = true;
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool
> > +lower_indirects_impl(nir_function_impl *impl, uint32_t mode_mask)
> > +{
> > + struct lower_indirect_state state;
> > +
> > + state.progress = false;
> > + state.mode_mask = mode_mask;
> > + nir_builder_init(&state.builder, impl);
> > +
> > + nir_foreach_block(impl, lower_indirect_block, &state);
> > +
> > + if (state.progress)
> > + nir_metadata_preserve(impl, nir_metadata_none);
> > +
> > + return state.progress;
> > +}
> > +
> > +/** Lowers indirect variable loads/stores to direct loads/stores.
> > + *
> > + * The pass works by replacing any indirect load or store with an
> if-ladder
> > + * that does a binary search on the array index.
> > + */
> > +bool
> > +nir_lower_indirect_derefs(nir_shader *shader, uint32_t mode_mask)
> > +{
> > + bool progress = false;
> > +
> > + nir_foreach_function(shader, function) {
> > + if (function->impl)
> > + progress = lower_indirects_impl(function->impl, mode_mask) ||
> progress;
> > + }
> > +
> > + return progress;
> > +}
> > --
> > 2.5.0.400.gff86faf
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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