[Mesa-dev] [PATCH 3/6] nir: add variant of lower_io_to_scalar to be called earlier
Timothy Arceri
tarceri at itsqueeze.com
Fri Oct 6 02:14:26 UTC 2017
This is intended to be called before nir_lower_io() so that we
can do some linking optimisations with the results. It can also
be used with drivers that don't use nir_lower_io() at all such
as RADV.
---
src/compiler/nir/nir.h | 2 +
src/compiler/nir/nir_lower_io_to_scalar.c | 261 ++++++++++++++++++++++++++++++
2 files changed, 263 insertions(+)
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index bb5aba605a1..b4b89e8961a 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2452,6 +2452,8 @@ bool nir_lower_load_const_to_scalar(nir_shader *shader);
bool nir_lower_read_invocation_to_scalar(nir_shader *shader);
bool nir_lower_phis_to_scalar(nir_shader *shader);
void nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask);
+void nir_lower_io_to_scalar_early(nir_shader *shader, unsigned first,
+ unsigned last);
bool nir_lower_samplers(nir_shader *shader,
const struct gl_shader_program *shader_program);
diff --git a/src/compiler/nir/nir_lower_io_to_scalar.c b/src/compiler/nir/nir_lower_io_to_scalar.c
index fffd1d3d2bb..4a7d86261f7 100644
--- a/src/compiler/nir/nir_lower_io_to_scalar.c
+++ b/src/compiler/nir/nir_lower_io_to_scalar.c
@@ -127,3 +127,264 @@ nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask)
}
}
}
+
+static nir_variable **
+get_channel_variables(struct hash_table *ht, nir_variable *var)
+{
+ nir_variable **chan_vars;
+ struct hash_entry *entry = _mesa_hash_table_search(ht, var);
+ if (!entry) {
+ chan_vars = (nir_variable **) calloc(4, sizeof(nir_variable *));
+ _mesa_hash_table_insert(ht, var, chan_vars);
+ } else {
+ chan_vars = (nir_variable **) entry->data;
+ }
+
+ return chan_vars;
+}
+
+/*
+ * This function differs from nir_deref_clone() in that it gets its type from
+ * the parent deref rather than our source deref. This is useful when splitting
+ * vectors because we want to use the scalar type of the new parent rather than
+ * then the old vector type.
+ */
+static nir_deref_array *
+clone_deref_array(const nir_deref_array *darr, nir_deref *parent)
+{
+ nir_deref_array *ndarr = nir_deref_array_create(parent);
+
+ ndarr->deref.type = glsl_get_array_element(parent->type);
+ if (darr->deref.child)
+ ndarr->deref.child =
+ &clone_deref_array(nir_deref_as_array(darr->deref.child),
+ &ndarr->deref)->deref;
+
+ ndarr->deref_array_type = darr->deref_array_type;
+ ndarr->base_offset = darr->base_offset;
+ if (ndarr->deref_array_type == nir_deref_array_type_indirect)
+ nir_src_copy(&ndarr->indirect, &darr->indirect, parent);
+
+ return ndarr;
+}
+
+static void
+lower_load_to_scalar_early(nir_builder *b, nir_intrinsic_instr *intr,
+ nir_variable *var, struct hash_table *split_inputs,
+ struct hash_table *split_outputs)
+{
+ b->cursor = nir_before_instr(&intr->instr);
+
+ assert(intr->dest.is_ssa);
+
+ nir_ssa_def *loads[4];
+
+ nir_variable **chan_vars;
+ if (var->data.mode == nir_var_shader_in) {
+ chan_vars = get_channel_variables(split_inputs, var);
+ } else {
+ chan_vars = get_channel_variables(split_outputs, var);
+ }
+
+ for (unsigned i = 0; i < intr->num_components; i++) {
+ nir_variable *chan_var = chan_vars[var->data.location_frac + i];
+ if (!chan_vars[var->data.location_frac + i]) {
+ chan_var = nir_variable_clone(var, b->shader);
+ chan_var->data.location_frac = var->data.location_frac + i;
+ chan_var->type = glsl_channel_type(chan_var->type);
+
+ chan_vars[var->data.location_frac + i] = chan_var;
+
+ nir_shader_add_variable(b->shader, chan_var);
+ }
+
+ nir_intrinsic_instr *chan_intr =
+ nir_intrinsic_instr_create(b->shader, intr->intrinsic);
+ nir_ssa_dest_init(&chan_intr->instr, &chan_intr->dest,
+ 1, intr->dest.ssa.bit_size, NULL);
+ chan_intr->num_components = 1;
+ chan_intr->variables[0] = nir_deref_var_create(chan_intr, chan_var);
+
+ if (intr->variables[0]->deref.child) {
+ chan_intr->variables[0]->deref.child =
+ &clone_deref_array(nir_deref_as_array(intr->variables[0]->deref.child),
+ &chan_intr->variables[0]->deref)->deref;
+ }
+
+ if (intr->intrinsic == nir_intrinsic_interp_var_at_offset ||
+ intr->intrinsic == nir_intrinsic_interp_var_at_sample)
+ nir_src_copy(chan_intr->src, intr->src, &chan_intr->instr);
+
+ nir_builder_instr_insert(b, &chan_intr->instr);
+
+ loads[i] = &chan_intr->dest.ssa;
+ }
+
+ nir_ssa_def_rewrite_uses(&intr->dest.ssa,
+ nir_src_for_ssa(nir_vec(b, loads,
+ intr->num_components)));
+
+ /* Remove the old load intrinsic */
+ nir_instr_remove(&intr->instr);
+}
+
+static void
+lower_store_output_to_scalar_early(nir_builder *b, nir_intrinsic_instr *intr,
+ nir_variable *var,
+ struct hash_table *split_outputs)
+{
+ b->cursor = nir_before_instr(&intr->instr);
+
+ nir_ssa_def *value = nir_ssa_for_src(b, intr->src[0], intr->num_components);
+
+ nir_variable **chan_vars = get_channel_variables(split_outputs, var);
+ for (unsigned i = 0; i < intr->num_components; i++) {
+ if (!(nir_intrinsic_write_mask(intr) & (1 << i)))
+ continue;
+
+ nir_variable *chan_var = chan_vars[var->data.location_frac + i];
+ if (!chan_vars[var->data.location_frac + i]) {
+ chan_var = nir_variable_clone(var, b->shader);
+ chan_var->data.location_frac = var->data.location_frac + i;
+ chan_var->type = glsl_channel_type(chan_var->type);
+
+ chan_vars[var->data.location_frac + i] = chan_var;
+
+ nir_shader_add_variable(b->shader, chan_var);
+ }
+
+ nir_intrinsic_instr *chan_intr =
+ nir_intrinsic_instr_create(b->shader, intr->intrinsic);
+ chan_intr->num_components = 1;
+
+ nir_intrinsic_set_write_mask(chan_intr, 0x1);
+
+ chan_intr->variables[0] = nir_deref_var_create(chan_intr, chan_var);
+ chan_intr->src[0] = nir_src_for_ssa(nir_channel(b, value, i));
+
+ if (intr->variables[0]->deref.child) {
+ chan_intr->variables[0]->deref.child =
+ &clone_deref_array(nir_deref_as_array(intr->variables[0]->deref.child),
+ &chan_intr->variables[0]->deref)->deref;
+ }
+
+ nir_builder_instr_insert(b, &chan_intr->instr);
+ }
+
+ /* Remove the old store intrinsic */
+ nir_instr_remove(&intr->instr);
+}
+
+/*
+ * This function is intended to be called earlier than nir_lower_io_to_scalar()
+ * i.e. before nir_lower_io() is called.
+ */
+void
+nir_lower_io_to_scalar_early(nir_shader *shader, unsigned first, unsigned last)
+{
+ nir_variable_mode mask = 0;
+ if (shader->info.stage != first)
+ mask |= nir_var_shader_in;
+
+ if (shader->info.stage != last)
+ mask |= nir_var_shader_out;
+
+ struct hash_table *split_inputs =
+ _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+ struct hash_table *split_outputs =
+ _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ nir_builder b;
+ nir_builder_init(&b, function->impl);
+
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr_safe(instr, block) {
+ if (instr->type != nir_instr_type_intrinsic)
+ continue;
+
+ nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
+
+ if (intr->num_components == 1)
+ continue;
+
+ if (intr->intrinsic != nir_intrinsic_load_var &&
+ intr->intrinsic != nir_intrinsic_store_var &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_centroid &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_sample &&
+ intr->intrinsic != nir_intrinsic_interp_var_at_offset)
+ continue;
+
+ nir_variable *var = intr->variables[0]->var;
+ nir_variable_mode mode = var->data.mode;
+
+ /* TODO: add patch support */
+ if (var->data.patch)
+ continue;
+
+ /* TODO: add doubles support */
+ if (glsl_type_is_64bit(glsl_without_array(var->type)))
+ continue;
+
+ if (var->data.location < VARYING_SLOT_VAR0 &&
+ var->data.location >= 0)
+ continue;
+
+ /* Don't bother splitting if we can't opt away any unused
+ * components.
+ */
+ if (var->data.always_active_io)
+ continue;
+
+ /* Skip types we cannot split */
+ if (glsl_type_is_matrix(glsl_without_array(var->type)) ||
+ glsl_type_is_struct(glsl_without_array(var->type)))
+ continue;
+
+ switch (intr->intrinsic) {
+ case nir_intrinsic_interp_var_at_centroid:
+ case nir_intrinsic_interp_var_at_sample:
+ case nir_intrinsic_interp_var_at_offset:
+ case nir_intrinsic_load_var:
+ if ((mask & nir_var_shader_in && mode == nir_var_shader_in) ||
+ (mask & nir_var_shader_out && mode == nir_var_shader_out))
+ lower_load_to_scalar_early(&b, intr, var, split_inputs,
+ split_outputs);
+ break;
+ case nir_intrinsic_store_var:
+ if (mask & nir_var_shader_out &&
+ mode == nir_var_shader_out)
+ lower_store_output_to_scalar_early(&b, intr, var,
+ split_outputs);
+ break;
+ default:
+ break;
+ }
+ }
+ }
+ }
+ }
+
+ /* Remove old input from the shaders inputs list */
+ struct hash_entry *entry;
+ hash_table_foreach(split_inputs, entry) {
+ nir_variable *var = (nir_variable *) entry->key;
+ exec_node_remove(&var->node);
+
+ free(entry->data);
+ }
+
+ /* Remove old output from the shaders outputs list */
+ hash_table_foreach(split_outputs, entry) {
+ nir_variable *var = (nir_variable *) entry->key;
+ exec_node_remove(&var->node);
+
+ free(entry->data);
+ }
+
+ _mesa_hash_table_destroy(split_inputs, NULL);
+ _mesa_hash_table_destroy(split_outputs, NULL);
+}
--
2.13.6
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