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/*
* Copyright © 2018 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 "nir.h"
#include "nir_builder.h"
#include "util/fast_idiv_by_const.h"
#include "util/u_math.h"
static nir_ssa_def *
build_udiv(nir_builder *b, nir_ssa_def *n, uint64_t d)
{
if (d == 0) {
return nir_imm_intN_t(b, 0, n->bit_size);
} else if (util_is_power_of_two_or_zero64(d)) {
return nir_ushr(b, n, nir_imm_int(b, util_logbase2_64(d)));
} else {
struct util_fast_udiv_info m =
util_compute_fast_udiv_info(d, n->bit_size, n->bit_size);
if (m.pre_shift)
n = nir_ushr(b, n, nir_imm_int(b, m.pre_shift));
if (m.increment)
n = nir_uadd_sat(b, n, nir_imm_intN_t(b, m.increment, n->bit_size));
n = nir_umul_high(b, n, nir_imm_intN_t(b, m.multiplier, n->bit_size));
if (m.post_shift)
n = nir_ushr(b, n, nir_imm_int(b, m.post_shift));
return n;
}
}
static nir_ssa_def *
build_umod(nir_builder *b, nir_ssa_def *n, uint64_t d)
{
if (d == 0) {
return nir_imm_intN_t(b, 0, n->bit_size);
} else if (util_is_power_of_two_or_zero64(d)) {
return nir_iand(b, n, nir_imm_intN_t(b, d - 1, n->bit_size));
} else {
return nir_isub(b, n, nir_imul(b, build_udiv(b, n, d),
nir_imm_intN_t(b, d, n->bit_size)));
}
}
static nir_ssa_def *
build_idiv(nir_builder *b, nir_ssa_def *n, int64_t d)
{
if (d == 0) {
return nir_imm_intN_t(b, 0, n->bit_size);
} else if (d == 1) {
return n;
} else if (d == -1) {
return nir_ineg(b, n);
} else if (util_is_power_of_two_or_zero64(d)) {
uint64_t abs_d = d < 0 ? -d : d;
nir_ssa_def *uq = nir_ishr(b, n, nir_imm_int(b, util_logbase2_64(abs_d)));
nir_ssa_def *n_neg = nir_ilt(b, n, nir_imm_intN_t(b, 0, n->bit_size));
nir_ssa_def *neg = d < 0 ? nir_inot(b, n_neg) : n_neg;
return nir_bcsel(b, neg, nir_ineg(b, uq), uq);
} else {
struct util_fast_sdiv_info m =
util_compute_fast_sdiv_info(d, n->bit_size);
nir_ssa_def *res =
nir_imul_high(b, n, nir_imm_intN_t(b, m.multiplier, n->bit_size));
if (d > 0 && m.multiplier < 0)
res = nir_iadd(b, res, n);
if (d < 0 && m.multiplier > 0)
res = nir_isub(b, res, n);
if (m.shift)
res = nir_ishr(b, res, nir_imm_int(b, m.shift));
res = nir_iadd(b, res, nir_ushr(b, res, nir_imm_int(b, n->bit_size - 1)));
return res;
}
}
static bool
nir_opt_idiv_const_instr(nir_builder *b, nir_alu_instr *alu)
{
assert(alu->dest.dest.is_ssa);
assert(alu->src[0].src.is_ssa && alu->src[1].src.is_ssa);
nir_const_value *const_denom = nir_src_as_const_value(alu->src[1].src);
if (!const_denom)
return false;
unsigned bit_size = alu->src[1].src.ssa->bit_size;
b->cursor = nir_before_instr(&alu->instr);
nir_ssa_def *q[4];
for (unsigned comp = 0; comp < alu->dest.dest.ssa.num_components; comp++) {
/* Get the numerator for the channel */
nir_ssa_def *n = nir_channel(b, alu->src[0].src.ssa,
alu->src[0].swizzle[comp]);
/* Get the denominator for the channel */
int64_t d;
switch (bit_size) {
case 8:
d = const_denom->i8[alu->src[1].swizzle[comp]];
break;
case 16:
d = const_denom->i16[alu->src[1].swizzle[comp]];
break;
case 32:
d = const_denom->i32[alu->src[1].swizzle[comp]];
break;
case 64:
d = const_denom->i64[alu->src[1].swizzle[comp]];
break;
default:
unreachable("Invalid bit size");
}
nir_alu_type d_type = nir_op_infos[alu->op].input_types[1];
if (nir_alu_type_get_base_type(d_type) == nir_type_uint) {
/* The code above sign-extended. If we're lowering an unsigned op,
* we need to mask it off to the correct number of bits so that a
* cast to uint64_t will do the right thing.
*/
if (bit_size < 64)
d &= (1ull << bit_size) - 1;
}
switch (alu->op) {
case nir_op_udiv:
q[comp] = build_udiv(b, n, d);
break;
case nir_op_idiv:
q[comp] = build_idiv(b, n, d);
break;
case nir_op_umod:
q[comp] = build_umod(b, n, d);
break;
default:
unreachable("Unknown integer division op");
}
}
nir_ssa_def *qvec = nir_vec(b, q, alu->dest.dest.ssa.num_components);
nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa, nir_src_for_ssa(qvec));
nir_instr_remove(&alu->instr);
return true;
}
static bool
nir_opt_idiv_const_impl(nir_function_impl *impl, unsigned min_bit_size)
{
bool progress = false;
nir_builder b;
nir_builder_init(&b, impl);
nir_foreach_block(block, impl) {
nir_foreach_instr_safe(instr, block) {
if (instr->type != nir_instr_type_alu)
continue;
nir_alu_instr *alu = nir_instr_as_alu(instr);
if (alu->op != nir_op_udiv &&
alu->op != nir_op_idiv &&
alu->op != nir_op_umod)
continue;
assert(alu->dest.dest.is_ssa);
if (alu->dest.dest.ssa.bit_size < min_bit_size)
continue;
progress |= nir_opt_idiv_const_instr(&b, alu);
}
}
if (progress) {
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance);
}
return progress;
}
bool
nir_opt_idiv_const(nir_shader *shader, unsigned min_bit_size)
{
bool progress = false;
nir_foreach_function(function, shader) {
if (function->impl)
progress |= nir_opt_idiv_const_impl(function->impl, min_bit_size);
}
return progress;
}
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