Mesa (master): nir: Add a pass for propagating invariant decorations
Jason Ekstrand
jekstrand at kemper.freedesktop.org
Mon Jun 20 19:05:44 UTC 2016
Module: Mesa
Branch: master
Commit: 202751fbb7e3d35c1aa84f325f862245dab67f6c
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=202751fbb7e3d35c1aa84f325f862245dab67f6c
Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date: Mon Jun 13 12:47:19 2016 -0700
nir: Add a pass for propagating invariant decorations
This pass is similar to propagate_invariance in the GLSL compiler. The
real "output" of this pass is that any algebraic operations which are
eventually consumed by an invariant variable get marked as "exact".
Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Cc: "12.0" <mesa-stable at lists.freedesktop.org>
---
src/compiler/Makefile.sources | 1 +
src/compiler/nir/nir.h | 2 +
src/compiler/nir/nir_propagate_invariant.c | 196 +++++++++++++++++++++++++++++
3 files changed, 199 insertions(+)
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index 5c4ea65..0ff9b23 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -231,6 +231,7 @@ NIR_FILES = \
nir/nir_phi_builder.c \
nir/nir_phi_builder.h \
nir/nir_print.c \
+ nir/nir_propagate_invariant.c \
nir/nir_remove_dead_variables.c \
nir/nir_repair_ssa.c \
nir/nir_search.c \
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index ec7b0c7..1725ee3 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2290,6 +2290,8 @@ bool nir_lower_returns(nir_shader *shader);
bool nir_inline_functions(nir_shader *shader);
+bool nir_propagate_invariant(nir_shader *shader);
+
void nir_lower_var_copy_instr(nir_intrinsic_instr *copy, void *mem_ctx);
void nir_lower_var_copies(nir_shader *shader);
diff --git a/src/compiler/nir/nir_propagate_invariant.c b/src/compiler/nir/nir_propagate_invariant.c
new file mode 100644
index 0000000..7b5bd6c
--- /dev/null
+++ b/src/compiler/nir/nir_propagate_invariant.c
@@ -0,0 +1,196 @@
+/*
+ * 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"
+
+static void
+add_src(nir_src *src, struct set *invariants)
+{
+ if (src->is_ssa) {
+ _mesa_set_add(invariants, src->ssa);
+ } else {
+ _mesa_set_add(invariants, src->reg.reg);
+ }
+}
+
+static bool
+add_src_cb(nir_src *src, void *state)
+{
+ add_src(src, state);
+ return true;
+}
+
+static bool
+dest_is_invariant(nir_dest *dest, struct set *invariants)
+{
+ if (dest->is_ssa) {
+ return _mesa_set_search(invariants, &dest->ssa);
+ } else {
+ return _mesa_set_search(invariants, dest->reg.reg);
+ }
+}
+
+static void
+add_cf_node(nir_cf_node *cf, struct set *invariants)
+{
+ if (cf->type == nir_cf_node_if) {
+ nir_if *if_stmt = nir_cf_node_as_if(cf);
+ add_src(&if_stmt->condition, invariants);
+ }
+
+ if (cf->parent)
+ add_cf_node(cf->parent, invariants);
+}
+
+static void
+add_var(nir_variable *var, struct set *invariants)
+{
+ _mesa_set_add(invariants, var);
+}
+
+static bool
+var_is_invariant(nir_variable *var, struct set * invariants)
+{
+ return var->data.invariant || _mesa_set_search(invariants, var);
+}
+
+static void
+propagate_invariant_instr(nir_instr *instr, struct set *invariants)
+{
+ switch (instr->type) {
+ case nir_instr_type_alu: {
+ nir_alu_instr *alu = nir_instr_as_alu(instr);
+ if (!dest_is_invariant(&alu->dest.dest, invariants))
+ break;
+
+ alu->exact = true;
+ nir_foreach_src(instr, add_src_cb, invariants);
+ break;
+ }
+
+ case nir_instr_type_tex: {
+ nir_tex_instr *tex = nir_instr_as_tex(instr);
+ if (dest_is_invariant(&tex->dest, invariants))
+ nir_foreach_src(instr, add_src_cb, invariants);
+ break;
+ }
+
+ case nir_instr_type_intrinsic: {
+ nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_copy_var:
+ /* If the destination is invariant then so is the source */
+ if (var_is_invariant(intrin->variables[0]->var, invariants))
+ add_var(intrin->variables[1]->var, invariants);
+ break;
+
+ case nir_intrinsic_load_var:
+ if (dest_is_invariant(&intrin->dest, invariants))
+ add_var(intrin->variables[0]->var, invariants);
+ break;
+
+ case nir_intrinsic_store_var:
+ if (var_is_invariant(intrin->variables[0]->var, invariants))
+ add_src(&intrin->src[0], invariants);
+ break;
+
+ default:
+ /* Nothing to do */
+ break;
+ }
+ }
+
+ case nir_instr_type_jump:
+ case nir_instr_type_ssa_undef:
+ case nir_instr_type_load_const:
+ break; /* Nothing to do */
+
+ case nir_instr_type_phi: {
+ nir_phi_instr *phi = nir_instr_as_phi(instr);
+ if (!dest_is_invariant(&phi->dest, invariants))
+ break;
+
+ nir_foreach_phi_src(src, phi) {
+ add_src(&src->src, invariants);
+ add_cf_node(&src->pred->cf_node, invariants);
+ }
+ break;
+ }
+
+ case nir_instr_type_call:
+ unreachable("This pass must be run after function inlining");
+
+ case nir_instr_type_parallel_copy:
+ default:
+ unreachable("Cannot have this instruction type");
+ }
+}
+
+static bool
+propagate_invariant_impl(nir_function_impl *impl, struct set *invariants)
+{
+ bool progress = false;
+
+ while (true) {
+ uint32_t prev_entries = invariants->entries;
+
+ nir_foreach_block_reverse(block, impl) {
+ nir_foreach_instr_reverse(instr, block)
+ propagate_invariant_instr(instr, invariants);
+ }
+
+ /* Keep running until we make no more progress. */
+ if (invariants->entries > prev_entries) {
+ progress = true;
+ continue;
+ } else {
+ break;
+ }
+ }
+
+ if (progress) {
+ nir_metadata_preserve(impl, nir_metadata_block_index |
+ nir_metadata_dominance |
+ nir_metadata_live_ssa_defs);
+ }
+
+ return progress;
+}
+
+bool
+nir_propagate_invariant(nir_shader *shader)
+{
+ /* Hash set of invariant things */
+ struct set *invariants = _mesa_set_create(NULL, _mesa_hash_pointer,
+ _mesa_key_pointer_equal);
+
+ bool progress = false;
+ nir_foreach_function(function, shader) {
+ if (function->impl && propagate_invariant_impl(function->impl, invariants))
+ progress = true;
+ }
+
+ _mesa_set_destroy(invariants, NULL);
+
+ return progress;
+}
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