[Mesa-dev] [PATCH 13/16] i965/fs: Add a saturation propagation optimization pass.
Jordan Justen
jljusten at gmail.com
Fri Jan 17 14:02:39 PST 2014
On Thu, Dec 19, 2013 at 1:40 PM, Matt Turner <mattst88 at gmail.com> wrote:
> 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: 1512588 -> 1501297 (-0.75%)
> instructions in affected programs: 723097 -> 711806 (-1.56%)
> GAINED: 0
> LOST: 4
> ---
> 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 | 102 +++++++++++++++++++++
> 4 files changed, 105 insertions(+)
> create mode 100644 src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
>
> diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources
> index 36d8261..3f901da 100644
> --- a/src/mesa/drivers/dri/i965/Makefile.sources
> +++ b/src/mesa/drivers/dri/i965/Makefile.sources
> @@ -62,6 +62,7 @@ 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_value_numbering.cpp \
> brw_fs_vector_splitting.cpp \
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> index 08837da..12b6d4a 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> @@ -3304,6 +3304,7 @@ fs_visitor::run()
> progress = opt_peephole_sel() || progress;
> progress = dead_control_flow_eliminate(this) || progress;
> vn_progress = opt_value_numbering();
> + progress = opt_saturate_propagation() || progress;
> progress = register_coalesce() || progress;
> progress = compute_to_mrf() || progress;
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
> index 75de18e..07360ae 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs.h
> +++ b/src/mesa/drivers/dri/i965/brw_fs.h
> @@ -368,6 +368,7 @@ 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..91a1338
> --- /dev/null
> +++ b/src/mesa/drivers/dri/i965/brw_fs_saturate_propagation.cpp
> @@ -0,0 +1,102 @@
> +/*
> + * 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 &&
> + scan_inst->can_do_saturate()) {
> + scan_inst->saturate = true;
> + inst->saturate = false;
> + progress = true;
> + }
> + for (int i = 0; i < 3; i++) {
Tab here.
12 & 13 (with your proposed changes)
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
-Jordan
> + 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;
> +}
> --
> 1.8.3.2
>
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