[Mesa-dev] [PATCH] nir: Add a pass for lower indirect variable dereferences
Connor Abbott
cwabbott0 at gmail.com
Thu Feb 25 06:25:47 UTC 2016
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
Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>
> + 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
More information about the mesa-dev
mailing list