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/*
* 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;
nir_intrinsic_set_write_mask(store, nir_intrinsic_write_mask(orig_instr));
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;
}
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