src/compiler/nir/nir_lower_alu_to_scalar.c - third_party/mesa - Git at Google

 /*
  * Copyright © 2014-2015 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.
  */

 #include "nir.h"
 #include "nir_builder.h"

 /** @file nir_lower_alu_to_scalar.c
  *
  * Replaces nir_alu_instr operations with more than one channel used in the
  * arguments with individual per-channel operations.
  */

 static void
 nir_alu_ssa_dest_init(nir_alu_instr *instr, unsigned num_components,
                       unsigned bit_size)
 {
    nir_ssa_dest_init(&instr->instr, &instr->dest.dest, num_components,
                      bit_size, NULL);
    instr->dest.write_mask = (1 << num_components) - 1;
 }

 static void
 lower_reduction(nir_alu_instr *instr, nir_op chan_op, nir_op merge_op,
                 nir_builder *builder)
 {
    unsigned num_components = nir_op_infos[instr->op].input_sizes[0];

    nir_ssa_def *last = NULL;
    for (unsigned i = 0; i < num_components; i++) {
       nir_alu_instr *chan = nir_alu_instr_create(builder->shader, chan_op);
       nir_alu_ssa_dest_init(chan, 1, instr->dest.dest.ssa.bit_size);
       nir_alu_src_copy(&chan->src[0], &instr->src[0], chan);
       chan->src[0].swizzle[0] = chan->src[0].swizzle[i];
       if (nir_op_infos[chan_op].num_inputs > 1) {
          assert(nir_op_infos[chan_op].num_inputs == 2);
          nir_alu_src_copy(&chan->src[1], &instr->src[1], chan);
          chan->src[1].swizzle[0] = chan->src[1].swizzle[i];
       }
       chan->exact = instr->exact;

       nir_builder_instr_insert(builder, &chan->instr);

       if (i == 0) {
          last = &chan->dest.dest.ssa;
       } else {
          last = nir_build_alu(builder, merge_op,
                               last, &chan->dest.dest.ssa, NULL, NULL);
       }
    }

    assert(instr->dest.write_mask == 1);
    nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(last));
    nir_instr_remove(&instr->instr);
 }

 static bool
 lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
 {
    unsigned num_src = nir_op_infos[instr->op].num_inputs;
    unsigned i, chan;

    assert(instr->dest.dest.is_ssa);
    assert(instr->dest.write_mask != 0);

    b->cursor = nir_before_instr(&instr->instr);
    b->exact = instr->exact;

 #define LOWER_REDUCTION(name, chan, merge) \
    case name##2: \
    case name##3: \
    case name##4: \
       lower_reduction(instr, chan, merge, b); \
       return true;

    switch (instr->op) {
    case nir_op_vec4:
    case nir_op_vec3:
    case nir_op_vec2:
    case nir_op_cube_face_coord:
    case nir_op_cube_face_index:
       /* We don't need to scalarize these ops, they're the ones generated to
        * group up outputs into a value that can be SSAed.
        */
       return false;

    case nir_op_pack_half_2x16:
       if (!b->shader->options->lower_pack_half_2x16)
          return false;

       nir_ssa_def *src_vec2 = nir_ssa_for_alu_src(b, instr, 0);

       nir_ssa_def *val =
          nir_pack_half_2x16_split(b, nir_channel(b, src_vec2, 0),
                                      nir_channel(b, src_vec2, 1));

       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
       nir_instr_remove(&instr->instr);
       return true;

    case nir_op_unpack_unorm_4x8:
    case nir_op_unpack_snorm_4x8:
    case nir_op_unpack_unorm_2x16:
    case nir_op_unpack_snorm_2x16:
       /* There is no scalar version of these ops, unless we were to break it
        * down to bitshifts and math (which is definitely not intended).
        */
       return false;

    case nir_op_unpack_half_2x16: {
       if (!b->shader->options->lower_unpack_half_2x16)
          return false;

       nir_ssa_def *packed = nir_ssa_for_alu_src(b, instr, 0);

       nir_ssa_def *comps[2];
       comps[0] = nir_unpack_half_2x16_split_x(b, packed);
       comps[1] = nir_unpack_half_2x16_split_y(b, packed);
       nir_ssa_def *vec = nir_vec(b, comps, 2);

       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
       nir_instr_remove(&instr->instr);
       return true;
    }

    case nir_op_pack_uvec2_to_uint: {
       assert(b->shader->options->lower_pack_snorm_2x16 ||
              b->shader->options->lower_pack_unorm_2x16);

       nir_ssa_def *word = nir_extract_u16(b, nir_ssa_for_alu_src(b, instr, 0),
                                              nir_imm_int(b, 0));
       nir_ssa_def *val =
          nir_ior(b, nir_ishl(b, nir_channel(b, word, 1), nir_imm_int(b, 16)),
                                 nir_channel(b, word, 0));

       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
       nir_instr_remove(&instr->instr);
       break;
    }

    case nir_op_pack_uvec4_to_uint: {
       assert(b->shader->options->lower_pack_snorm_4x8 ||
              b->shader->options->lower_pack_unorm_4x8);

       nir_ssa_def *byte = nir_extract_u8(b, nir_ssa_for_alu_src(b, instr, 0),
                                             nir_imm_int(b, 0));
       nir_ssa_def *val =
          nir_ior(b, nir_ior(b, nir_ishl(b, nir_channel(b, byte, 3), nir_imm_int(b, 24)),
                                nir_ishl(b, nir_channel(b, byte, 2), nir_imm_int(b, 16))),
                     nir_ior(b, nir_ishl(b, nir_channel(b, byte, 1), nir_imm_int(b, 8)),
                                nir_channel(b, byte, 0)));

       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
       nir_instr_remove(&instr->instr);
       break;
    }

    case nir_op_fdph: {
       nir_ssa_def *src0_vec = nir_ssa_for_alu_src(b, instr, 0);
       nir_ssa_def *src1_vec = nir_ssa_for_alu_src(b, instr, 1);

       nir_ssa_def *sum[4];
       for (unsigned i = 0; i < 3; i++) {
          sum[i] = nir_fmul(b, nir_channel(b, src0_vec, i),
                               nir_channel(b, src1_vec, i));
       }
       sum[3] = nir_channel(b, src1_vec, 3);

       nir_ssa_def *val = nir_fadd(b, nir_fadd(b, sum[0], sum[1]),
                                      nir_fadd(b, sum[2], sum[3]));

       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
       nir_instr_remove(&instr->instr);
       return true;
    }

    case nir_op_unpack_64_2x32:
    case nir_op_unpack_32_2x16:
       return false;

       LOWER_REDUCTION(nir_op_fdot, nir_op_fmul, nir_op_fadd);
       LOWER_REDUCTION(nir_op_ball_fequal, nir_op_feq, nir_op_iand);
       LOWER_REDUCTION(nir_op_ball_iequal, nir_op_ieq, nir_op_iand);
       LOWER_REDUCTION(nir_op_bany_fnequal, nir_op_fne, nir_op_ior);
       LOWER_REDUCTION(nir_op_bany_inequal, nir_op_ine, nir_op_ior);
       LOWER_REDUCTION(nir_op_fall_equal, nir_op_seq, nir_op_fand);
       LOWER_REDUCTION(nir_op_fany_nequal, nir_op_sne, nir_op_for);

    default:
       break;
    }

    if (instr->dest.dest.ssa.num_components == 1)
       return false;

    unsigned num_components = instr->dest.dest.ssa.num_components;
    nir_ssa_def *comps[NIR_MAX_VEC_COMPONENTS] = { NULL };

    for (chan = 0; chan < NIR_MAX_VEC_COMPONENTS; chan++) {
       if (!(instr->dest.write_mask & (1 << chan)))
          continue;

       nir_alu_instr *lower = nir_alu_instr_create(b->shader, instr->op);
       for (i = 0; i < num_src; i++) {
          /* We only handle same-size-as-dest (input_sizes[] == 0) or scalar
           * args (input_sizes[] == 1).
           */
          assert(nir_op_infos[instr->op].input_sizes[i] < 2);
          unsigned src_chan = (nir_op_infos[instr->op].input_sizes[i] == 1 ?
                               0 : chan);

          nir_alu_src_copy(&lower->src[i], &instr->src[i], lower);
          for (int j = 0; j < NIR_MAX_VEC_COMPONENTS; j++)
             lower->src[i].swizzle[j] = instr->src[i].swizzle[src_chan];
       }

       nir_alu_ssa_dest_init(lower, 1, instr->dest.dest.ssa.bit_size);
       lower->dest.saturate = instr->dest.saturate;
       comps[chan] = &lower->dest.dest.ssa;
       lower->exact = instr->exact;

       nir_builder_instr_insert(b, &lower->instr);
    }

    nir_ssa_def *vec = nir_vec(b, comps, num_components);

    nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));

    nir_instr_remove(&instr->instr);
    return true;
 }

 static bool
 nir_lower_alu_to_scalar_impl(nir_function_impl *impl)
 {
    nir_builder builder;
    nir_builder_init(&builder, impl);
    bool progress = false;

    nir_foreach_block(block, impl) {
       nir_foreach_instr_safe(instr, block) {
          if (instr->type == nir_instr_type_alu) {
             progress = lower_alu_instr_scalar(nir_instr_as_alu(instr),
                                               &builder) || progress;
          }
       }
    }

    nir_metadata_preserve(impl, nir_metadata_block_index |
                                nir_metadata_dominance);

    return progress;
 }

 bool
 nir_lower_alu_to_scalar(nir_shader *shader)
 {
    bool progress = false;

    nir_foreach_function(function, shader) {
       if (function->impl)
          progress = nir_lower_alu_to_scalar_impl(function->impl) || progress;
    }

    return progress;
 }
	/*
	* Copyright © 2014-2015 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.
	*/

	#include "nir.h"
	#include "nir_builder.h"

	/** @file nir_lower_alu_to_scalar.c
	*
	* Replaces nir_alu_instr operations with more than one channel used in the
	* arguments with individual per-channel operations.
	*/

	static void
	nir_alu_ssa_dest_init(nir_alu_instr *instr, unsigned num_components,
	unsigned bit_size)
	{
	nir_ssa_dest_init(&instr->instr, &instr->dest.dest, num_components,
	bit_size, NULL);
	instr->dest.write_mask = (1 << num_components) - 1;
	}

	static void
	lower_reduction(nir_alu_instr *instr, nir_op chan_op, nir_op merge_op,
	nir_builder *builder)
	{
	unsigned num_components = nir_op_infos[instr->op].input_sizes[0];

	nir_ssa_def *last = NULL;
	for (unsigned i = 0; i < num_components; i++) {
	nir_alu_instr *chan = nir_alu_instr_create(builder->shader, chan_op);
	nir_alu_ssa_dest_init(chan, 1, instr->dest.dest.ssa.bit_size);
	nir_alu_src_copy(&chan->src[0], &instr->src[0], chan);
	chan->src[0].swizzle[0] = chan->src[0].swizzle[i];
	if (nir_op_infos[chan_op].num_inputs > 1) {
	assert(nir_op_infos[chan_op].num_inputs == 2);
	nir_alu_src_copy(&chan->src[1], &instr->src[1], chan);
	chan->src[1].swizzle[0] = chan->src[1].swizzle[i];
	}
	chan->exact = instr->exact;

	nir_builder_instr_insert(builder, &chan->instr);

	if (i == 0) {
	last = &chan->dest.dest.ssa;
	} else {
	last = nir_build_alu(builder, merge_op,
	last, &chan->dest.dest.ssa, NULL, NULL);
	}
	}

	assert(instr->dest.write_mask == 1);
	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(last));
	nir_instr_remove(&instr->instr);
	}

	static bool
	lower_alu_instr_scalar(nir_alu_instr instr, nir_builder b)
	{
	unsigned num_src = nir_op_infos[instr->op].num_inputs;
	unsigned i, chan;

	assert(instr->dest.dest.is_ssa);
	assert(instr->dest.write_mask != 0);

	b->cursor = nir_before_instr(&instr->instr);
	b->exact = instr->exact;

	#define LOWER_REDUCTION(name, chan, merge) \
	case name##2: \
	case name##3: \
	case name##4: \
	lower_reduction(instr, chan, merge, b); \
	return true;

	switch (instr->op) {
	case nir_op_vec4:
	case nir_op_vec3:
	case nir_op_vec2:
	case nir_op_cube_face_coord:
	case nir_op_cube_face_index:
	/* We don't need to scalarize these ops, they're the ones generated to
	* group up outputs into a value that can be SSAed.
	*/
	return false;

	case nir_op_pack_half_2x16:
	if (!b->shader->options->lower_pack_half_2x16)
	return false;

	nir_ssa_def *src_vec2 = nir_ssa_for_alu_src(b, instr, 0);

	nir_ssa_def *val =
	nir_pack_half_2x16_split(b, nir_channel(b, src_vec2, 0),
	nir_channel(b, src_vec2, 1));

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
	nir_instr_remove(&instr->instr);
	return true;

	case nir_op_unpack_unorm_4x8:
	case nir_op_unpack_snorm_4x8:
	case nir_op_unpack_unorm_2x16:
	case nir_op_unpack_snorm_2x16:
	/* There is no scalar version of these ops, unless we were to break it
	* down to bitshifts and math (which is definitely not intended).
	*/
	return false;

	case nir_op_unpack_half_2x16: {
	if (!b->shader->options->lower_unpack_half_2x16)
	return false;

	nir_ssa_def *packed = nir_ssa_for_alu_src(b, instr, 0);

	nir_ssa_def *comps[2];
	comps[0] = nir_unpack_half_2x16_split_x(b, packed);
	comps[1] = nir_unpack_half_2x16_split_y(b, packed);
	nir_ssa_def *vec = nir_vec(b, comps, 2);

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
	nir_instr_remove(&instr->instr);
	return true;
	}

	case nir_op_pack_uvec2_to_uint: {
	assert(b->shader->options->lower_pack_snorm_2x16 \|\|
	b->shader->options->lower_pack_unorm_2x16);

	nir_ssa_def *word = nir_extract_u16(b, nir_ssa_for_alu_src(b, instr, 0),
	nir_imm_int(b, 0));
	nir_ssa_def *val =
	nir_ior(b, nir_ishl(b, nir_channel(b, word, 1), nir_imm_int(b, 16)),
	nir_channel(b, word, 0));

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
	nir_instr_remove(&instr->instr);
	break;
	}

	case nir_op_pack_uvec4_to_uint: {
	assert(b->shader->options->lower_pack_snorm_4x8 \|\|
	b->shader->options->lower_pack_unorm_4x8);

	nir_ssa_def *byte = nir_extract_u8(b, nir_ssa_for_alu_src(b, instr, 0),
	nir_imm_int(b, 0));
	nir_ssa_def *val =
	nir_ior(b, nir_ior(b, nir_ishl(b, nir_channel(b, byte, 3), nir_imm_int(b, 24)),
	nir_ishl(b, nir_channel(b, byte, 2), nir_imm_int(b, 16))),
	nir_ior(b, nir_ishl(b, nir_channel(b, byte, 1), nir_imm_int(b, 8)),
	nir_channel(b, byte, 0)));

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
	nir_instr_remove(&instr->instr);
	break;
	}

	case nir_op_fdph: {
	nir_ssa_def *src0_vec = nir_ssa_for_alu_src(b, instr, 0);
	nir_ssa_def *src1_vec = nir_ssa_for_alu_src(b, instr, 1);

	nir_ssa_def *sum[4];
	for (unsigned i = 0; i < 3; i++) {
	sum[i] = nir_fmul(b, nir_channel(b, src0_vec, i),
	nir_channel(b, src1_vec, i));
	}
	sum[3] = nir_channel(b, src1_vec, 3);

	nir_ssa_def *val = nir_fadd(b, nir_fadd(b, sum[0], sum[1]),
	nir_fadd(b, sum[2], sum[3]));

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
	nir_instr_remove(&instr->instr);
	return true;
	}

	case nir_op_unpack_64_2x32:
	case nir_op_unpack_32_2x16:
	return false;

	LOWER_REDUCTION(nir_op_fdot, nir_op_fmul, nir_op_fadd);
	LOWER_REDUCTION(nir_op_ball_fequal, nir_op_feq, nir_op_iand);
	LOWER_REDUCTION(nir_op_ball_iequal, nir_op_ieq, nir_op_iand);
	LOWER_REDUCTION(nir_op_bany_fnequal, nir_op_fne, nir_op_ior);
	LOWER_REDUCTION(nir_op_bany_inequal, nir_op_ine, nir_op_ior);
	LOWER_REDUCTION(nir_op_fall_equal, nir_op_seq, nir_op_fand);
	LOWER_REDUCTION(nir_op_fany_nequal, nir_op_sne, nir_op_for);

	default:
	break;
	}

	if (instr->dest.dest.ssa.num_components == 1)
	return false;

	unsigned num_components = instr->dest.dest.ssa.num_components;
	nir_ssa_def *comps[NIR_MAX_VEC_COMPONENTS] = { NULL };

	for (chan = 0; chan < NIR_MAX_VEC_COMPONENTS; chan++) {
	if (!(instr->dest.write_mask & (1 << chan)))
	continue;

	nir_alu_instr *lower = nir_alu_instr_create(b->shader, instr->op);
	for (i = 0; i < num_src; i++) {
	/* We only handle same-size-as-dest (input_sizes[] == 0) or scalar
	* args (input_sizes[] == 1).
	*/
	assert(nir_op_infos[instr->op].input_sizes[i] < 2);
	unsigned src_chan = (nir_op_infos[instr->op].input_sizes[i] == 1 ?
	0 : chan);

	nir_alu_src_copy(&lower->src[i], &instr->src[i], lower);
	for (int j = 0; j < NIR_MAX_VEC_COMPONENTS; j++)
	lower->src[i].swizzle[j] = instr->src[i].swizzle[src_chan];
	}

	nir_alu_ssa_dest_init(lower, 1, instr->dest.dest.ssa.bit_size);
	lower->dest.saturate = instr->dest.saturate;
	comps[chan] = &lower->dest.dest.ssa;
	lower->exact = instr->exact;

	nir_builder_instr_insert(b, &lower->instr);
	}

	nir_ssa_def *vec = nir_vec(b, comps, num_components);

	nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));

	nir_instr_remove(&instr->instr);
	return true;
	}

	static bool
	nir_lower_alu_to_scalar_impl(nir_function_impl *impl)
	{
	nir_builder builder;
	nir_builder_init(&builder, impl);
	bool progress = false;

	nir_foreach_block(block, impl) {
	nir_foreach_instr_safe(instr, block) {
	if (instr->type == nir_instr_type_alu) {
	progress = lower_alu_instr_scalar(nir_instr_as_alu(instr),
	&builder) \|\| progress;
	}
	}
	}

	nir_metadata_preserve(impl, nir_metadata_block_index \|
	nir_metadata_dominance);

	return progress;
	}

	bool
	nir_lower_alu_to_scalar(nir_shader *shader)
	{
	bool progress = false;

	nir_foreach_function(function, shader) {
	if (function->impl)
	progress = nir_lower_alu_to_scalar_impl(function->impl) \|\| progress;
	}

	return progress;
	}