--- /dev/null
+/*
+ * Copyright © 2019 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
+build_write_masked_store(nir_builder *b, nir_deref_instr *vec_deref,
+ nir_ssa_def *value, unsigned component)
+{
+ assert(value->num_components == 1);
+ unsigned num_components = glsl_get_components(vec_deref->type);
+ assert(num_components > 1 && num_components <= NIR_MAX_VEC_COMPONENTS);
+
+ nir_ssa_def *u = nir_ssa_undef(b, 1, value->bit_size);
+ nir_ssa_def *comps[NIR_MAX_VEC_COMPONENTS];
+ for (unsigned i = 0; i < num_components; i++)
+ comps[i] = (i == component) ? value : u;
+
+ nir_ssa_def *vec = nir_vec(b, comps, num_components);
+ nir_store_deref(b, vec_deref, vec, (1u << component));
+}
+
+static void
+build_write_masked_stores(nir_builder *b, nir_deref_instr *vec_deref,
+ nir_ssa_def *value, nir_ssa_def *index,
+ unsigned start, unsigned end)
+{
+ if (start == end - 1) {
+ build_write_masked_store(b, vec_deref, value, start);
+ } else {
+ unsigned mid = start + (end - start) / 2;
+ nir_push_if(b, nir_ilt(b, index, nir_imm_int(b, mid)));
+ build_write_masked_stores(b, vec_deref, value, index, start, mid);
+ nir_push_else(b, NULL);
+ build_write_masked_stores(b, vec_deref, value, index, mid, end);
+ nir_pop_if(b, NULL);
+ }
+}
+
+static bool
+nir_lower_array_deref_of_vec_impl(nir_function_impl *impl,
+ nir_variable_mode modes,
+ nir_lower_array_deref_of_vec_options options)
+{
+ bool progress = false;
+
+ nir_builder b;
+ nir_builder_init(&b, impl);
+
+ nir_foreach_block(block, impl) {
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+ assert(intrin->intrinsic != nir_intrinsic_copy_deref);
+
+ if (intrin->intrinsic != nir_intrinsic_load_deref &&
+ intrin->intrinsic != nir_intrinsic_interp_deref_at_centroid &&
+ intrin->intrinsic != nir_intrinsic_interp_deref_at_sample &&
+ intrin->intrinsic != nir_intrinsic_interp_deref_at_offset &&
+ intrin->intrinsic != nir_intrinsic_store_deref)
+ continue;
+
+ nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
+ if (!(deref->mode & modes))
+ continue;
+
+ /* We only care about array derefs that act on vectors */
+ if (deref->deref_type != nir_deref_type_array)
+ continue;
+
+ nir_deref_instr *vec_deref = nir_deref_instr_parent(deref);
+ if (!glsl_type_is_vector(vec_deref->type))
+ continue;
+
+ assert(intrin->num_components == 1);
+ unsigned num_components = glsl_get_components(vec_deref->type);
+ assert(num_components > 1 && num_components <= NIR_MAX_VEC_COMPONENTS);
+
+ b.cursor = nir_after_instr(&intrin->instr);
+
+ if (intrin->intrinsic == nir_intrinsic_store_deref) {
+ assert(intrin->src[1].is_ssa);
+ nir_ssa_def *value = intrin->src[1].ssa;
+
+ if (nir_src_is_const(deref->arr.index)) {
+ if (!(options & nir_lower_direct_array_deref_of_vec_store))
+ continue;
+
+ unsigned index = nir_src_as_uint(deref->arr.index);
+ /* If index is OOB, we throw the old store away and don't
+ * replace it with anything.
+ */
+ if (index < num_components)
+ build_write_masked_store(&b, vec_deref, value, index);
+ } else {
+ if (!(options & nir_lower_indirect_array_deref_of_vec_store))
+ continue;
+
+ nir_ssa_def *index = nir_ssa_for_src(&b, deref->arr.index, 1);
+ build_write_masked_stores(&b, vec_deref, value, index,
+ 0, num_components);
+ }
+ nir_instr_remove(&intrin->instr);
+
+ progress = true;
+ } else {
+ if (nir_src_is_const(deref->arr.index)) {
+ if (!(options & nir_lower_direct_array_deref_of_vec_load))
+ continue;
+ } else {
+ if (!(options & nir_lower_indirect_array_deref_of_vec_load))
+ continue;
+ }
+
+ /* Turn the load into a vector load */
+ nir_instr_rewrite_src(&intrin->instr, &intrin->src[0],
+ nir_src_for_ssa(&vec_deref->dest.ssa));
+ intrin->dest.ssa.num_components = num_components;
+ intrin->num_components = num_components;
+
+ nir_ssa_def *index = nir_ssa_for_src(&b, deref->arr.index, 1);
+ nir_ssa_def *scalar =
+ nir_vector_extract(&b, &intrin->dest.ssa, index);
+ if (scalar->parent_instr->type == nir_instr_type_ssa_undef) {
+ nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
+ nir_src_for_ssa(scalar));
+ nir_instr_remove(&intrin->instr);
+ } else {
+ nir_ssa_def_rewrite_uses_after(&intrin->dest.ssa,
+ nir_src_for_ssa(scalar),
+ scalar->parent_instr);
+ }
+ progress = true;
+ }
+ }
+ }
+
+ if (progress) {
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+ }
+
+ return progress;
+}
+
+/* Lowers away array dereferences on vectors
+ *
+ * These are allowed on certain variable types such as SSBOs and TCS outputs.
+ * However, not everyone can actually handle them everywhere. There are also
+ * cases where we want to lower them for performance reasons.
+ *
+ * This patch assumes that copy_deref instructions have already been lowered.
+ */
+bool
+nir_lower_array_deref_of_vec(nir_shader *shader, nir_variable_mode modes,
+ nir_lower_array_deref_of_vec_options options)
+{
+ bool progress = false;
+
+ nir_foreach_function(function, shader) {
+ if (function->impl &&
+ nir_lower_array_deref_of_vec_impl(function->impl, modes, options))
+ progress = true;
+ }
+
+ return progress;
+}