Attachment 120957 Details for Bug 92760 – NIR indirect lowering pass

NIR indirect lowering pass

nir_lower_indirect_derefs.c (text/plain), 8.22 KB, created by Jason Ekstrand on 2016-01-11 18:02:36 UTC

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Creator: Jason Ekstrand

Created: 2016-01-11 18:02:36 UTC

Size: 8.22 KB

patch

obsolete

>/*
> * Copyright Â© 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 */
>      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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Attachments on bug 92760: 120957 | 122690

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