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;
}
bool
fs_visitor::dead_code_eliminate()
{
bool progress = false;
calculate_live_intervals();
int num_vars = live_intervals->num_vars;
BITSET_WORD *live = ralloc_array(NULL, BITSET_WORD, BITSET_WORDS(num_vars));
foreach_block (block, cfg) {
memcpy(live, live_intervals->bd[block->num].liveout,
sizeof(BITSET_WORD) * BITSET_WORDS(num_vars));
foreach_inst_in_block_reverse(fs_inst, inst, block) {
if (inst->dst.file == GRF &&
!inst->has_side_effects() &&
!inst->writes_flag()) {
bool result_live = false;
if (inst->regs_written == 1) {
int var = live_intervals->var_from_reg(&inst->dst);
result_live = BITSET_TEST(live, var);
} else {
int var = live_intervals->var_from_vgrf[inst->dst.reg];
for (int i = 0; i < inst->regs_written; i++) {
result_live = result_live || BITSET_TEST(live, var + i);
}
}
if (!result_live) {
progress = true;
if (inst->writes_accumulator) {
inst->dst = fs_reg(retype(brw_null_reg(), inst->dst.type));
} else {
inst->opcode = BRW_OPCODE_NOP;
continue;
}
}
}
if (inst->dst.file == GRF) {
if (!inst->is_partial_write()) {
int var = live_intervals->var_from_vgrf[inst->dst.reg];
for (int i = 0; i < inst->regs_written; i++) {
BITSET_CLEAR(live, var + inst->dst.reg_offset + i);
}
}
}
for (int i = 0; i < inst->sources; i++) {
if (inst->src[i].file == GRF) {
int var = live_intervals->var_from_vgrf[inst->src[i].reg];
for (int j = 0; j < inst->regs_read(this, i); j++) {
BITSET_SET(live, var + inst->src[i].reg_offset + j);
}
}
}
}
}
