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/*
* Copyright © 2012 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_cfg.h"
namespace { /* avoid conflict with opt_copy_propagation_elements */
struct acp_entry : public exec_node {
fs_reg dst;
fs_reg src;
};
}
bool
fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
{
if (inst->src[arg].file != entry->dst.file ||
inst->src[arg].reg != entry->dst.reg ||
inst->src[arg].reg_offset != entry->dst.reg_offset) {
return false;
}
/* See resolve_ud_negate() and comment in brw_fs_emit.cpp. */
if (inst->conditional_mod &&
inst->src[arg].type == BRW_REGISTER_TYPE_UD &&
entry->src.negate)
return false;
bool has_source_modifiers = entry->src.abs || entry->src.negate;
if (intel->gen == 6 && inst->is_math() &&
(has_source_modifiers || entry->src.file == UNIFORM))
return false;
inst->src[arg].file = entry->src.file;
inst->src[arg].reg = entry->src.reg;
inst->src[arg].reg_offset = entry->src.reg_offset;
if (!inst->src[arg].abs) {
inst->src[arg].abs = entry->src.abs;
inst->src[arg].negate ^= entry->src.negate;
}
return true;
}
/** @file brw_fs_copy_propagation.cpp
*
* Support for local copy propagation by walking the list of instructions
* and maintaining the ACP table of available copies for propagation.
*
* See Muchnik's Advanced Compiler Design and Implementation, section
* 12.5 (p356).
*/
/* Walks a basic block and does copy propagation on it using the acp
* list.
*/
bool
fs_visitor::opt_copy_propagate_local(void *mem_ctx,
fs_bblock *block, exec_list *acp)
{
bool progress = false;
for (fs_inst *inst = block->start;
inst != block->end->next;
inst = (fs_inst *)inst->next) {
/* Try propagating into this instruction. */
foreach_list(entry_node, acp) {
acp_entry *entry = (acp_entry *)entry_node;
for (int i = 0; i < 3; i++) {
if (try_copy_propagate(inst, i, entry))
progress = true;
}
}
/* kill the destination from the ACP */
if (inst->dst.file == GRF) {
foreach_list_safe(entry_node, acp) {
acp_entry *entry = (acp_entry *)entry_node;
if (inst->overwrites_reg(entry->dst) ||
inst->overwrites_reg(entry->src)) {
entry->remove();
}
}
}
/* If this instruction is a raw copy, add it to the ACP. */
if (inst->opcode == BRW_OPCODE_MOV &&
inst->dst.file == GRF &&
((inst->src[0].file == GRF &&
(inst->src[0].reg != inst->dst.reg ||
inst->src[0].reg_offset != inst->dst.reg_offset)) ||
inst->src[0].file == UNIFORM) &&
inst->src[0].type == inst->dst.type &&
!inst->saturate &&
!inst->predicated &&
!inst->force_uncompressed &&
!inst->force_sechalf &&
inst->src[0].smear == -1) {
acp_entry *entry = ralloc(mem_ctx, acp_entry);
entry->dst = inst->dst;
entry->src = inst->src[0];
acp->push_tail(entry);
}
}
return progress;
}
bool
fs_visitor::opt_copy_propagate()
{
bool progress = false;
void *mem_ctx = ralloc_context(this->mem_ctx);
fs_cfg cfg(this);
for (int b = 0; b < cfg.num_blocks; b++) {
fs_bblock *block = cfg.blocks[b];
exec_list acp;
progress = opt_copy_propagate_local(mem_ctx, block, &acp) || progress;
}
ralloc_free(mem_ctx);
if (progress)
live_intervals_valid = false;
return progress;
}
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