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/*
* 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
*
* Implements a pass that propagates the SAT modifier from a MOV.SAT into the
* instruction that produced the source of the MOV.SAT, thereby allowing the
* MOV's src and dst to be coalesced and the MOV removed.
*
* For instance,
*
* ADD tmp, src0, src1
* MOV.SAT dst, tmp
*
* would be transformed into
*
* ADD.SAT tmp, src0, src1
* MOV dst, tmp
*/
static bool
opt_saturate_propagation_local(fs_visitor *v, bblock_t *block)
{
bool progress = false;
int ip = block->end_ip + 1;
foreach_inst_in_block_reverse(fs_inst, inst, block) {
ip--;
if (inst->opcode != BRW_OPCODE_MOV ||
!inst->saturate ||
inst->dst.file != GRF ||
inst->dst.type != inst->src[0].type ||
inst->src[0].file != GRF ||
inst->src[0].abs ||
inst->src[0].negate)
continue;
int src_var = v->live_intervals->var_from_reg(inst->src[0]);
int src_end_ip = v->live_intervals->end[src_var];
bool interfered = false;
foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst, inst) {
if (scan_inst->overwrites_reg(inst->src[0])) {
if (scan_inst->is_partial_write() ||
(scan_inst->dst.type != inst->dst.type &&
!scan_inst->can_change_types()))
break;
if (scan_inst->saturate) {
inst->saturate = false;
progress = true;
} else if (src_end_ip <= ip || inst->dst.equals(inst->src[0])) {
if (scan_inst->can_do_saturate()) {
if (scan_inst->dst.type != inst->dst.type) {
scan_inst->dst.type = inst->dst.type;
for (int i = 0; i < scan_inst->sources; i++) {
scan_inst->src[i].type = inst->dst.type;
}
}
scan_inst->saturate = true;
inst->saturate = false;
progress = true;
}
}
break;
}
for (int i = 0; i < scan_inst->sources; 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) {
if (scan_inst->opcode != BRW_OPCODE_MOV ||
!scan_inst->saturate ||
scan_inst->src[0].abs ||
scan_inst->src[0].negate) {
interfered = true;
break;
}
}
}
if (interfered)
break;
}
}
return progress;
}
bool
fs_visitor::opt_saturate_propagation()
{
bool progress = false;
calculate_live_intervals();
foreach_block (block, cfg) {
progress = opt_saturate_propagation_local(this, block) || progress;
}
/* Live intervals are still valid. */
return progress;
}
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