Mesa (master): i965/fs: Add a saturation propagation optimization pass.
Matt Turner
mattst88 at kemper.freedesktop.org
Wed Jan 29 01:46:33 UTC 2014
Module: Mesa
Branch: master
Commit: 947c828d5cbffe9640ac63103a6223112eeff27f
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=947c828d5cbffe9640ac63103a6223112eeff27f
Author: Matt Turner <mattst88 at gmail.com>
Date: Thu Dec 12 00:30:16 2013 -0800
i965/fs: Add a saturation propagation optimization pass.
Transforms, for example,
mul vgrf3, vgrf2, vgrf1
mov.sat vgrf4, vgrf3
into
mul.sat vgrf3, vgrf2, vgrf1
mov vgrf4, vgrf3
which gives register_coalescing an opportunity to remove the MOV
instruction.
total instructions in shared programs: 1515039 -> 1504634 (-0.69%)
instructions in affected programs: 798586 -> 788181 (-1.30%)
GAINED: 0
LOST: 4
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
---
src/mesa/drivers/dri/i965/Makefile.sources | 1 +
src/mesa/drivers/dri/i965/brw_fs.cpp | 1 +
src/mesa/drivers/dri/i965/brw_fs.h | 1 +
.../dri/i965/brw_fs_saturate_propagation.cpp | 104 ++++++++++++++++++++
4 files changed, 107 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources
index a3fb417..4c5a2a0 100644
--- a/src/mesa/drivers/dri/i965/Makefile.sources
+++ b/src/mesa/drivers/dri/i965/Makefile.sources
@@ -63,6 +63,7 @@ i965_FILES = \
brw_fs_live_variables.cpp \
brw_fs_peephole_predicated_break.cpp \
brw_fs_reg_allocate.cpp \
+ brw_fs_saturate_propagation.cpp \
brw_fs_sel_peephole.cpp \
brw_fs_vector_splitting.cpp \
brw_fs_visitor.cpp \
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 1e6c3e0..d7301dd 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3362,6 +3362,7 @@ fs_visitor::run()
progress = dead_code_eliminate_local() || progress;
progress = opt_peephole_sel() || progress;
progress = dead_control_flow_eliminate(this) || progress;
+ progress = opt_saturate_propagation() || progress;
progress = register_coalesce() || progress;
progress = compute_to_mrf() || progress;
} while (progress);
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 2ccb8c4..9c5c13a 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -371,6 +371,7 @@ public:
void try_replace_with_sel();
bool opt_peephole_sel();
bool opt_peephole_predicated_break();
+ bool opt_saturate_propagation();
void emit_bool_to_cond_code(ir_rvalue *condition);
void emit_if_gen6(ir_if *ir);
void emit_unspill(fs_inst *inst, fs_reg reg, uint32_t spill_offset,
diff --git a/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
new file mode 100644
index 0000000..9c2e451
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright © 2013 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 "brw_fs.h"
+#include "brw_fs_live_variables.h"
+#include "brw_cfg.h"
+
+/** @file brw_fs_saturate_propagation.cpp
+ */
+
+static bool
+opt_saturate_propagation_local(fs_visitor *v, bblock_t *block)
+{
+ bool progress = false;
+ int ip = block->start_ip;
+
+ for (fs_inst *inst = (fs_inst *)block->start;
+ inst != block->end->next;
+ inst = (fs_inst *) inst->next) {
+ ip++;
+
+ if (inst->opcode != BRW_OPCODE_MOV ||
+ inst->dst.file != GRF ||
+ !inst->saturate)
+ continue;
+
+ int src_var = v->live_intervals->var_from_reg(&inst->src[0]);
+ int src_end_ip = v->live_intervals->end[src_var];
+ if (src_end_ip > ip && !inst->dst.equals(inst->src[0]))
+ continue;
+
+ int scan_ip = ip;
+ bool interfered = false;
+ for (fs_inst *scan_inst = (fs_inst *) inst->prev;
+ scan_inst != block->start->prev;
+ scan_inst = (fs_inst *) scan_inst->prev) {
+ scan_ip--;
+
+ if (scan_inst->dst.file == GRF &&
+ scan_inst->dst.reg == inst->src[0].reg &&
+ scan_inst->dst.reg_offset == inst->src[0].reg_offset) {
+ if (scan_inst->can_do_saturate()) {
+ scan_inst->saturate = true;
+ inst->saturate = false;
+ progress = true;
+ }
+ break;
+ }
+ for (int i = 0; i < 3; i++) {
+ if (scan_inst->src[i].file == GRF &&
+ scan_inst->src[i].reg == inst->src[0].reg &&
+ scan_inst->src[i].reg_offset == inst->src[0].reg_offset) {
+ interfered = true;
+ break;
+ }
+ }
+
+ if (interfered)
+ break;
+ }
+ }
+
+ return progress;
+}
+
+bool
+fs_visitor::opt_saturate_propagation()
+{
+ bool progress = false;
+
+ calculate_live_intervals();
+
+ cfg_t cfg(&instructions);
+
+ for (int b = 0; b < cfg.num_blocks; b++) {
+ progress = opt_saturate_propagation_local(this, cfg.blocks[b])
+ || progress;
+ }
+
+ if (progress)
+ invalidate_live_intervals();
+
+ return progress;
+}
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