Mesa (master): nir: Add an IO scalarizing pass using the intrinsic' s first_component.
Eric Anholt
anholt at kemper.freedesktop.org
Fri Aug 19 20:13:40 UTC 2016
Module: Mesa
Branch: master
Commit: 9f1411d1ecc0029f4a6697849e657ac7b2a64f94
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=9f1411d1ecc0029f4a6697849e657ac7b2a64f94
Author: Eric Anholt <eric at anholt.net>
Date: Thu Aug 4 12:42:45 2016 -0700
nir: Add an IO scalarizing pass using the intrinsic's first_component.
vc4 wants to have per-scalar IO load/stores so that dead code elimination
can happen on a more granular basis, which it has been doing in the
backend using a multiplication by 4 of the intrinsic's driver_location.
We can represent it properly in the NIR using the first_component field,
though.
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
---
src/compiler/Makefile.sources | 1 +
src/compiler/nir/nir.h | 1 +
src/compiler/nir/nir_lower_io_to_scalar.c | 129 ++++++++++++++++++++++++++++++
3 files changed, 131 insertions(+)
diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
index a2dd234..cfb6359 100644
--- a/src/compiler/Makefile.sources
+++ b/src/compiler/Makefile.sources
@@ -203,6 +203,7 @@ NIR_FILES = \
nir/nir_lower_indirect_derefs.c \
nir/nir_lower_io.c \
nir/nir_lower_io_to_temporaries.c \
+ nir/nir_lower_io_to_scalar.c \
nir/nir_lower_io_types.c \
nir/nir_lower_passthrough_edgeflags.c \
nir/nir_lower_phis_to_scalar.c \
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index e09cf3b..5e527d8 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2395,6 +2395,7 @@ void nir_lower_alu_to_scalar(nir_shader *shader);
void nir_lower_load_const_to_scalar(nir_shader *shader);
void nir_lower_phis_to_scalar(nir_shader *shader);
+void nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask);
void 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
new file mode 100644
index 0000000..f2345d5
--- /dev/null
+++ b/src/compiler/nir/nir_lower_io_to_scalar.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright © 2016 Broadcom
+ *
+ * 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"
+
+/** @file nir_lower_io_to_scalar.c
+ *
+ * Replaces nir_load_input/nir_store_output operations with num_components !=
+ * 1 with individual per-channel operations.
+ */
+
+static void
+lower_load_input_to_scalar(nir_builder *b, nir_intrinsic_instr *intr)
+{
+ b->cursor = nir_before_instr(&intr->instr);
+
+ assert(intr->dest.is_ssa);
+
+ nir_ssa_def *loads[4];
+
+ for (unsigned i = 0; i < intr->num_components; i++) {
+ 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;
+
+ nir_intrinsic_set_base(chan_intr, nir_intrinsic_base(intr));
+ nir_intrinsic_set_component(chan_intr, nir_intrinsic_component(intr) + i);
+ /* offset */
+ chan_intr->src[0] = intr->src[0];
+
+ 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)));
+ nir_instr_remove(&intr->instr);
+}
+
+static void
+lower_store_output_to_scalar(nir_builder *b, nir_intrinsic_instr *intr)
+{
+ b->cursor = nir_before_instr(&intr->instr);
+
+ nir_ssa_def *value = nir_ssa_for_src(b, intr->src[0], intr->num_components);
+
+ for (unsigned i = 0; i < intr->num_components; i++) {
+ if (!(nir_intrinsic_write_mask(intr) & (1 << i)))
+ continue;
+
+ nir_intrinsic_instr *chan_intr =
+ nir_intrinsic_instr_create(b->shader, intr->intrinsic);
+ chan_intr->num_components = 1;
+
+ nir_intrinsic_set_base(chan_intr, nir_intrinsic_base(intr));
+ nir_intrinsic_set_write_mask(chan_intr, 0x1);
+ nir_intrinsic_set_component(chan_intr, nir_intrinsic_component(intr) + i);
+
+ /* value */
+ chan_intr->src[0] = nir_src_for_ssa(nir_channel(b, value, i));
+ /* offset */
+ chan_intr->src[1] = intr->src[1];
+
+ nir_builder_instr_insert(b, &chan_intr->instr);
+ }
+
+ nir_instr_remove(&intr->instr);
+}
+
+void
+nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask)
+{
+ 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;
+
+ switch (intr->intrinsic) {
+ case nir_intrinsic_load_input:
+ if (mask & nir_var_shader_in)
+ lower_load_input_to_scalar(&b, intr);
+ break;
+ case nir_intrinsic_store_output:
+ if (mask & nir_var_shader_out)
+ lower_store_output_to_scalar(&b, intr);
+ break;
+ default:
+ break;
+ }
+ }
+ }
+ }
+ }
+}
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