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/*
* Copyright © 2014 Broadcom
*
* 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.
*/
/**
* @file vc4_opt_algebraic.c
*
* This is the optimization pass for miscellaneous changes to instructions
* where we can simplify the operation by some knowledge about the specific
* operations.
*
* Mostly this will be a matter of turning things into MOVs so that they can
* later be copy-propagated out.
*/
#include "vc4_qir.h"
#include "util/u_math.h"
static bool debug;
static void
dump_from(struct vc4_compile *c, struct qinst *inst)
{
if (!debug)
return;
fprintf(stderr, "optimizing: ");
qir_dump_inst(c, inst);
fprintf(stderr, "\n");
}
static void
dump_to(struct vc4_compile *c, struct qinst *inst)
{
if (!debug)
return;
fprintf(stderr, "to: ");
qir_dump_inst(c, inst);
fprintf(stderr, "\n");
}
static bool
is_zero(struct vc4_compile *c, struct qinst **defs, struct qreg reg)
{
reg = qir_follow_movs(defs, reg);
return (reg.file == QFILE_UNIF &&
c->uniform_contents[reg.index] == QUNIFORM_CONSTANT &&
c->uniform_data[reg.index] == 0);
}
static bool
is_1f(struct vc4_compile *c, struct qinst **defs, struct qreg reg)
{
reg = qir_follow_movs(defs, reg);
return (reg.file == QFILE_UNIF &&
c->uniform_contents[reg.index] == QUNIFORM_CONSTANT &&
c->uniform_data[reg.index] == fui(1.0));
}
static void
replace_with_mov(struct vc4_compile *c, struct qinst *inst, struct qreg arg)
{
dump_from(c, inst);
inst->op = QOP_MOV;
inst->src[0] = arg;
inst->src[1] = c->undef;
dump_to(c, inst);
}
static bool
add_replace_zero(struct vc4_compile *c,
struct qinst **defs,
struct qinst *inst,
int arg)
{
if (!is_zero(c, defs, inst->src[arg]))
return false;
replace_with_mov(c, inst, inst->src[1 - arg]);
return true;
}
static bool
fmul_replace_zero(struct vc4_compile *c,
struct qinst **defs,
struct qinst *inst,
int arg)
{
if (!is_zero(c, defs, inst->src[arg]))
return false;
replace_with_mov(c, inst, inst->src[arg]);
return true;
}
static bool
fmul_replace_one(struct vc4_compile *c,
struct qinst **defs,
struct qinst *inst,
int arg)
{
if (!is_1f(c, defs, inst->src[arg]))
return false;
replace_with_mov(c, inst, inst->src[1 - arg]);
return true;
}
bool
qir_opt_algebraic(struct vc4_compile *c)
{
bool progress = false;
struct simple_node *node;
struct qinst *defs[c->num_temps];
foreach(node, &c->instructions) {
struct qinst *inst = (struct qinst *)node;
if (inst->dst.file == QFILE_TEMP)
defs[inst->dst.index] = inst;
switch (inst->op) {
case QOP_SF:
/* SF just looks at the sign bit, or whether all the
* bits are 0. This is preserved across an itof
* transformation.
*/
if (inst->src[0].file == QFILE_TEMP &&
defs[inst->src[0].index]->op == QOP_ITOF) {
dump_from(c, inst);
inst->src[0] =
defs[inst->src[0].index]->src[0];
progress = true;
dump_to(c, inst);
break;
}
break;
case QOP_SEL_X_Y_ZS:
case QOP_SEL_X_Y_ZC:
case QOP_SEL_X_Y_NS:
case QOP_SEL_X_Y_NC:
if (qir_reg_equals(inst->src[0], inst->src[1])) {
/* Turn "dst = (sf == x) ? a : a)" into
* "dst = a"
*/
replace_with_mov(c, inst, inst->src[1]);
progress = true;
break;
}
if (is_zero(c, defs, inst->src[1])) {
/* Replace references to a 0 uniform value
* with the SEL_X_0 equivalent.
*/
dump_from(c, inst);
inst->op -= (QOP_SEL_X_Y_ZS - QOP_SEL_X_0_ZS);
inst->src[1] = c->undef;
progress = true;
dump_to(c, inst);
break;
}
if (is_zero(c, defs, inst->src[0])) {
/* Replace references to a 0 uniform value
* with the SEL_X_0 equivalent, flipping the
* condition being evaluated since the operand
* order is flipped.
*/
dump_from(c, inst);
inst->op -= QOP_SEL_X_Y_ZS;
inst->op ^= 1;
inst->op += QOP_SEL_X_0_ZS;
inst->src[0] = inst->src[1];
inst->src[1] = c->undef;
progress = true;
dump_to(c, inst);
break;
}
break;
case QOP_FSUB:
case QOP_SUB:
if (is_zero(c, defs, inst->src[1])) {
replace_with_mov(c, inst, inst->src[0]);
}
break;
case QOP_ADD:
if (add_replace_zero(c, defs, inst, 0) ||
add_replace_zero(c, defs, inst, 1)) {
progress = true;
break;
}
break;
case QOP_FADD:
if (add_replace_zero(c, defs, inst, 0) ||
add_replace_zero(c, defs, inst, 1)) {
progress = true;
break;
}
/* FADD(a, FSUB(0, b)) -> FSUB(a, b) */
if (inst->src[1].file == QFILE_TEMP &&
defs[inst->src[1].index]->op == QOP_FSUB) {
struct qinst *fsub = defs[inst->src[1].index];
if (is_zero(c, defs, fsub->src[0])) {
dump_from(c, inst);
inst->op = QOP_FSUB;
inst->src[1] = fsub->src[1];
progress = true;
dump_to(c, inst);
break;
}
}
/* FADD(FSUB(0, b), a) -> FSUB(a, b) */
if (inst->src[0].file == QFILE_TEMP &&
defs[inst->src[0].index]->op == QOP_FSUB) {
struct qinst *fsub = defs[inst->src[0].index];
if (is_zero(c, defs, fsub->src[0])) {
dump_from(c, inst);
inst->op = QOP_FSUB;
inst->src[0] = inst->src[1];
inst->src[1] = fsub->src[1];
dump_to(c, inst);
progress = true;
break;
}
}
break;
case QOP_FMUL:
if (fmul_replace_zero(c, defs, inst, 0) ||
fmul_replace_zero(c, defs, inst, 1) ||
fmul_replace_one(c, defs, inst, 0) ||
fmul_replace_one(c, defs, inst, 1)) {
progress = true;
break;
}
break;
default:
break;
}
}
return progress;
}
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