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      1 /*
      2  * Copyright  2015 Intel Corporation
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the "Software"),
      6  * to deal in the Software without restriction, including without limitation
      7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8  * and/or sell copies of the Software, and to permit persons to whom the
      9  * Software is furnished to do so, subject to the following conditions:
     10  *
     11  * The above copyright notice and this permission notice (including the next
     12  * paragraph) shall be included in all copies or substantial portions of the
     13  * Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     21  * IN THE SOFTWARE.
     22  */
     23 
     24 #include "brw_nir.h"
     25 #include "brw_vec4.h"
     26 #include "brw_vec4_builder.h"
     27 #include "brw_vec4_surface_builder.h"
     28 #include "brw_program.h"
     29 
     30 using namespace brw;
     31 using namespace brw::surface_access;
     32 
     33 namespace brw {
     34 
     35 void
     36 vec4_visitor::emit_nir_code()
     37 {
     38    if (nir->num_uniforms > 0)
     39       nir_setup_uniforms();
     40 
     41    nir_setup_system_values();
     42 
     43    /* get the main function and emit it */
     44    nir_foreach_function(function, nir) {
     45       assert(strcmp(function->name, "main") == 0);
     46       assert(function->impl);
     47       nir_emit_impl(function->impl);
     48    }
     49 }
     50 
     51 void
     52 vec4_visitor::nir_setup_system_value_intrinsic(nir_intrinsic_instr *instr)
     53 {
     54    dst_reg *reg;
     55 
     56    switch (instr->intrinsic) {
     57    case nir_intrinsic_load_vertex_id:
     58       unreachable("should be lowered by lower_vertex_id().");
     59 
     60    case nir_intrinsic_load_vertex_id_zero_base:
     61       reg = &nir_system_values[SYSTEM_VALUE_VERTEX_ID_ZERO_BASE];
     62       if (reg->file == BAD_FILE)
     63          *reg = *make_reg_for_system_value(SYSTEM_VALUE_VERTEX_ID_ZERO_BASE);
     64       break;
     65 
     66    case nir_intrinsic_load_base_vertex:
     67       reg = &nir_system_values[SYSTEM_VALUE_BASE_VERTEX];
     68       if (reg->file == BAD_FILE)
     69          *reg = *make_reg_for_system_value(SYSTEM_VALUE_BASE_VERTEX);
     70       break;
     71 
     72    case nir_intrinsic_load_instance_id:
     73       reg = &nir_system_values[SYSTEM_VALUE_INSTANCE_ID];
     74       if (reg->file == BAD_FILE)
     75          *reg = *make_reg_for_system_value(SYSTEM_VALUE_INSTANCE_ID);
     76       break;
     77 
     78    case nir_intrinsic_load_base_instance:
     79       reg = &nir_system_values[SYSTEM_VALUE_BASE_INSTANCE];
     80       if (reg->file == BAD_FILE)
     81          *reg = *make_reg_for_system_value(SYSTEM_VALUE_BASE_INSTANCE);
     82       break;
     83 
     84    case nir_intrinsic_load_draw_id:
     85       reg = &nir_system_values[SYSTEM_VALUE_DRAW_ID];
     86       if (reg->file == BAD_FILE)
     87          *reg = *make_reg_for_system_value(SYSTEM_VALUE_DRAW_ID);
     88       break;
     89 
     90    default:
     91       break;
     92    }
     93 }
     94 
     95 static bool
     96 setup_system_values_block(nir_block *block, vec4_visitor *v)
     97 {
     98    nir_foreach_instr(instr, block) {
     99       if (instr->type != nir_instr_type_intrinsic)
    100          continue;
    101 
    102       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
    103       v->nir_setup_system_value_intrinsic(intrin);
    104    }
    105 
    106    return true;
    107 }
    108 
    109 void
    110 vec4_visitor::nir_setup_system_values()
    111 {
    112    nir_system_values = ralloc_array(mem_ctx, dst_reg, SYSTEM_VALUE_MAX);
    113    for (unsigned i = 0; i < SYSTEM_VALUE_MAX; i++) {
    114       nir_system_values[i] = dst_reg();
    115    }
    116 
    117    nir_foreach_function(function, nir) {
    118       assert(strcmp(function->name, "main") == 0);
    119       assert(function->impl);
    120       nir_foreach_block(block, function->impl) {
    121          setup_system_values_block(block, this);
    122       }
    123    }
    124 }
    125 
    126 void
    127 vec4_visitor::nir_setup_uniforms()
    128 {
    129    uniforms = nir->num_uniforms / 16;
    130 }
    131 
    132 void
    133 vec4_visitor::nir_emit_impl(nir_function_impl *impl)
    134 {
    135    nir_locals = ralloc_array(mem_ctx, dst_reg, impl->reg_alloc);
    136    for (unsigned i = 0; i < impl->reg_alloc; i++) {
    137       nir_locals[i] = dst_reg();
    138    }
    139 
    140    foreach_list_typed(nir_register, reg, node, &impl->registers) {
    141       unsigned array_elems =
    142          reg->num_array_elems == 0 ? 1 : reg->num_array_elems;
    143       const unsigned num_regs = array_elems * DIV_ROUND_UP(reg->bit_size, 32);
    144       nir_locals[reg->index] = dst_reg(VGRF, alloc.allocate(num_regs));
    145 
    146       if (reg->bit_size == 64)
    147          nir_locals[reg->index].type = BRW_REGISTER_TYPE_DF;
    148    }
    149 
    150    nir_ssa_values = ralloc_array(mem_ctx, dst_reg, impl->ssa_alloc);
    151 
    152    nir_emit_cf_list(&impl->body);
    153 }
    154 
    155 void
    156 vec4_visitor::nir_emit_cf_list(exec_list *list)
    157 {
    158    exec_list_validate(list);
    159    foreach_list_typed(nir_cf_node, node, node, list) {
    160       switch (node->type) {
    161       case nir_cf_node_if:
    162          nir_emit_if(nir_cf_node_as_if(node));
    163          break;
    164 
    165       case nir_cf_node_loop:
    166          nir_emit_loop(nir_cf_node_as_loop(node));
    167          break;
    168 
    169       case nir_cf_node_block:
    170          nir_emit_block(nir_cf_node_as_block(node));
    171          break;
    172 
    173       default:
    174          unreachable("Invalid CFG node block");
    175       }
    176    }
    177 }
    178 
    179 void
    180 vec4_visitor::nir_emit_if(nir_if *if_stmt)
    181 {
    182    /* First, put the condition in f0 */
    183    src_reg condition = get_nir_src(if_stmt->condition, BRW_REGISTER_TYPE_D, 1);
    184    vec4_instruction *inst = emit(MOV(dst_null_d(), condition));
    185    inst->conditional_mod = BRW_CONDITIONAL_NZ;
    186 
    187    /* We can just predicate based on the X channel, as the condition only
    188     * goes on its own line */
    189    emit(IF(BRW_PREDICATE_ALIGN16_REPLICATE_X));
    190 
    191    nir_emit_cf_list(&if_stmt->then_list);
    192 
    193    /* note: if the else is empty, dead CF elimination will remove it */
    194    emit(BRW_OPCODE_ELSE);
    195 
    196    nir_emit_cf_list(&if_stmt->else_list);
    197 
    198    emit(BRW_OPCODE_ENDIF);
    199 }
    200 
    201 void
    202 vec4_visitor::nir_emit_loop(nir_loop *loop)
    203 {
    204    emit(BRW_OPCODE_DO);
    205 
    206    nir_emit_cf_list(&loop->body);
    207 
    208    emit(BRW_OPCODE_WHILE);
    209 }
    210 
    211 void
    212 vec4_visitor::nir_emit_block(nir_block *block)
    213 {
    214    nir_foreach_instr(instr, block) {
    215       nir_emit_instr(instr);
    216    }
    217 }
    218 
    219 void
    220 vec4_visitor::nir_emit_instr(nir_instr *instr)
    221 {
    222    base_ir = instr;
    223 
    224    switch (instr->type) {
    225    case nir_instr_type_load_const:
    226       nir_emit_load_const(nir_instr_as_load_const(instr));
    227       break;
    228 
    229    case nir_instr_type_intrinsic:
    230       nir_emit_intrinsic(nir_instr_as_intrinsic(instr));
    231       break;
    232 
    233    case nir_instr_type_alu:
    234       nir_emit_alu(nir_instr_as_alu(instr));
    235       break;
    236 
    237    case nir_instr_type_jump:
    238       nir_emit_jump(nir_instr_as_jump(instr));
    239       break;
    240 
    241    case nir_instr_type_tex:
    242       nir_emit_texture(nir_instr_as_tex(instr));
    243       break;
    244 
    245    case nir_instr_type_ssa_undef:
    246       nir_emit_undef(nir_instr_as_ssa_undef(instr));
    247       break;
    248 
    249    default:
    250       fprintf(stderr, "VS instruction not yet implemented by NIR->vec4\n");
    251       break;
    252    }
    253 }
    254 
    255 static dst_reg
    256 dst_reg_for_nir_reg(vec4_visitor *v, nir_register *nir_reg,
    257                     unsigned base_offset, nir_src *indirect)
    258 {
    259    dst_reg reg;
    260 
    261    reg = v->nir_locals[nir_reg->index];
    262    if (nir_reg->bit_size == 64)
    263       reg.type = BRW_REGISTER_TYPE_DF;
    264    reg = offset(reg, 8, base_offset);
    265    if (indirect) {
    266       reg.reladdr =
    267          new(v->mem_ctx) src_reg(v->get_nir_src(*indirect,
    268                                                 BRW_REGISTER_TYPE_D,
    269                                                 1));
    270    }
    271    return reg;
    272 }
    273 
    274 dst_reg
    275 vec4_visitor::get_nir_dest(const nir_dest &dest)
    276 {
    277    if (dest.is_ssa) {
    278       dst_reg dst =
    279          dst_reg(VGRF, alloc.allocate(DIV_ROUND_UP(dest.ssa.bit_size, 32)));
    280       if (dest.ssa.bit_size == 64)
    281          dst.type = BRW_REGISTER_TYPE_DF;
    282       nir_ssa_values[dest.ssa.index] = dst;
    283       return dst;
    284    } else {
    285       return dst_reg_for_nir_reg(this, dest.reg.reg, dest.reg.base_offset,
    286                                  dest.reg.indirect);
    287    }
    288 }
    289 
    290 dst_reg
    291 vec4_visitor::get_nir_dest(const nir_dest &dest, enum brw_reg_type type)
    292 {
    293    return retype(get_nir_dest(dest), type);
    294 }
    295 
    296 dst_reg
    297 vec4_visitor::get_nir_dest(const nir_dest &dest, nir_alu_type type)
    298 {
    299    return get_nir_dest(dest, brw_type_for_nir_type(type));
    300 }
    301 
    302 src_reg
    303 vec4_visitor::get_nir_src(const nir_src &src, enum brw_reg_type type,
    304                           unsigned num_components)
    305 {
    306    dst_reg reg;
    307 
    308    if (src.is_ssa) {
    309       assert(src.ssa != NULL);
    310       reg = nir_ssa_values[src.ssa->index];
    311    }
    312    else {
    313       reg = dst_reg_for_nir_reg(this, src.reg.reg, src.reg.base_offset,
    314                                 src.reg.indirect);
    315    }
    316 
    317    reg = retype(reg, type);
    318 
    319    src_reg reg_as_src = src_reg(reg);
    320    reg_as_src.swizzle = brw_swizzle_for_size(num_components);
    321    return reg_as_src;
    322 }
    323 
    324 src_reg
    325 vec4_visitor::get_nir_src(const nir_src &src, nir_alu_type type,
    326                           unsigned num_components)
    327 {
    328    return get_nir_src(src, brw_type_for_nir_type(type), num_components);
    329 }
    330 
    331 src_reg
    332 vec4_visitor::get_nir_src(const nir_src &src, unsigned num_components)
    333 {
    334    /* if type is not specified, default to signed int */
    335    return get_nir_src(src, nir_type_int32, num_components);
    336 }
    337 
    338 src_reg
    339 vec4_visitor::get_indirect_offset(nir_intrinsic_instr *instr)
    340 {
    341    nir_src *offset_src = nir_get_io_offset_src(instr);
    342    nir_const_value *const_value = nir_src_as_const_value(*offset_src);
    343 
    344    if (const_value) {
    345       /* The only constant offset we should find is 0.  brw_nir.c's
    346        * add_const_offset_to_base() will fold other constant offsets
    347        * into instr->const_index[0].
    348        */
    349       assert(const_value->u32[0] == 0);
    350       return src_reg();
    351    }
    352 
    353    return get_nir_src(*offset_src, BRW_REGISTER_TYPE_UD, 1);
    354 }
    355 
    356 void
    357 vec4_visitor::nir_emit_load_const(nir_load_const_instr *instr)
    358 {
    359    dst_reg reg;
    360 
    361    if (instr->def.bit_size == 64) {
    362       reg = dst_reg(VGRF, alloc.allocate(2));
    363       reg.type = BRW_REGISTER_TYPE_DF;
    364    } else {
    365       reg = dst_reg(VGRF, alloc.allocate(1));
    366       reg.type = BRW_REGISTER_TYPE_D;
    367    }
    368 
    369    unsigned remaining = brw_writemask_for_size(instr->def.num_components);
    370 
    371    /* @FIXME: consider emitting vector operations to save some MOVs in
    372     * cases where the components are representable in 8 bits.
    373     * For now, we emit a MOV for each distinct value.
    374     */
    375    for (unsigned i = 0; i < instr->def.num_components; i++) {
    376       unsigned writemask = 1 << i;
    377 
    378       if ((remaining & writemask) == 0)
    379          continue;
    380 
    381       for (unsigned j = i; j < instr->def.num_components; j++) {
    382          if ((instr->def.bit_size == 32 &&
    383               instr->value.u32[i] == instr->value.u32[j]) ||
    384              (instr->def.bit_size == 64 &&
    385               instr->value.f64[i] == instr->value.f64[j])) {
    386             writemask |= 1 << j;
    387          }
    388       }
    389 
    390       reg.writemask = writemask;
    391       if (instr->def.bit_size == 64) {
    392          emit(MOV(reg, setup_imm_df(instr->value.f64[i])));
    393       } else {
    394          emit(MOV(reg, brw_imm_d(instr->value.i32[i])));
    395       }
    396 
    397       remaining &= ~writemask;
    398    }
    399 
    400    /* Set final writemask */
    401    reg.writemask = brw_writemask_for_size(instr->def.num_components);
    402 
    403    nir_ssa_values[instr->def.index] = reg;
    404 }
    405 
    406 void
    407 vec4_visitor::nir_emit_intrinsic(nir_intrinsic_instr *instr)
    408 {
    409    dst_reg dest;
    410    src_reg src;
    411 
    412    switch (instr->intrinsic) {
    413 
    414    case nir_intrinsic_load_input: {
    415       nir_const_value *const_offset = nir_src_as_const_value(instr->src[0]);
    416 
    417       /* We set EmitNoIndirectInput for VS */
    418       assert(const_offset);
    419 
    420       dest = get_nir_dest(instr->dest);
    421       dest.writemask = brw_writemask_for_size(instr->num_components);
    422 
    423       src = src_reg(ATTR, instr->const_index[0] + const_offset->u32[0],
    424                     glsl_type::uvec4_type);
    425       src = retype(src, dest.type);
    426 
    427       bool is_64bit = nir_dest_bit_size(instr->dest) == 64;
    428       if (is_64bit) {
    429          dst_reg tmp = dst_reg(this, glsl_type::dvec4_type);
    430          src.swizzle = BRW_SWIZZLE_XYZW;
    431          shuffle_64bit_data(tmp, src, false);
    432          emit(MOV(dest, src_reg(tmp)));
    433       } else {
    434          /* Swizzle source based on component layout qualifier */
    435          src.swizzle = BRW_SWZ_COMP_INPUT(nir_intrinsic_component(instr));
    436          emit(MOV(dest, src));
    437       }
    438       break;
    439    }
    440 
    441    case nir_intrinsic_store_output: {
    442       nir_const_value *const_offset = nir_src_as_const_value(instr->src[1]);
    443       assert(const_offset);
    444 
    445       int varying = instr->const_index[0] + const_offset->u32[0];
    446 
    447       bool is_64bit = nir_src_bit_size(instr->src[0]) == 64;
    448       if (is_64bit) {
    449          src_reg data;
    450          src = get_nir_src(instr->src[0], BRW_REGISTER_TYPE_DF,
    451                            instr->num_components);
    452          data = src_reg(this, glsl_type::dvec4_type);
    453          shuffle_64bit_data(dst_reg(data), src, true);
    454          src = retype(data, BRW_REGISTER_TYPE_F);
    455       } else {
    456          src = get_nir_src(instr->src[0], BRW_REGISTER_TYPE_F,
    457                            instr->num_components);
    458       }
    459 
    460       unsigned c = nir_intrinsic_component(instr);
    461       output_reg[varying][c] = dst_reg(src);
    462       output_num_components[varying][c] = instr->num_components;
    463 
    464       unsigned num_components = instr->num_components;
    465       if (is_64bit)
    466          num_components *= 2;
    467 
    468       output_reg[varying][c] = dst_reg(src);
    469       output_num_components[varying][c] = MIN2(4, num_components);
    470 
    471       if (is_64bit && num_components > 4) {
    472          assert(num_components <= 8);
    473          output_reg[varying + 1][c] = byte_offset(dst_reg(src), REG_SIZE);
    474          output_num_components[varying + 1][c] = num_components - 4;
    475       }
    476       break;
    477    }
    478 
    479    case nir_intrinsic_get_buffer_size: {
    480       nir_const_value *const_uniform_block = nir_src_as_const_value(instr->src[0]);
    481       unsigned ssbo_index = const_uniform_block ? const_uniform_block->u32[0] : 0;
    482 
    483       const unsigned index =
    484          prog_data->base.binding_table.ssbo_start + ssbo_index;
    485       dst_reg result_dst = get_nir_dest(instr->dest);
    486       vec4_instruction *inst = new(mem_ctx)
    487          vec4_instruction(VS_OPCODE_GET_BUFFER_SIZE, result_dst);
    488 
    489       inst->base_mrf = 2;
    490       inst->mlen = 1; /* always at least one */
    491       inst->src[1] = brw_imm_ud(index);
    492 
    493       /* MRF for the first parameter */
    494       src_reg lod = brw_imm_d(0);
    495       int param_base = inst->base_mrf;
    496       int writemask = WRITEMASK_X;
    497       emit(MOV(dst_reg(MRF, param_base, glsl_type::int_type, writemask), lod));
    498 
    499       emit(inst);
    500 
    501       brw_mark_surface_used(&prog_data->base, index);
    502       break;
    503    }
    504 
    505    case nir_intrinsic_store_ssbo: {
    506       assert(devinfo->gen >= 7);
    507 
    508       /* Block index */
    509       src_reg surf_index;
    510       nir_const_value *const_uniform_block =
    511          nir_src_as_const_value(instr->src[1]);
    512       if (const_uniform_block) {
    513          unsigned index = prog_data->base.binding_table.ssbo_start +
    514                           const_uniform_block->u32[0];
    515          surf_index = brw_imm_ud(index);
    516          brw_mark_surface_used(&prog_data->base, index);
    517       } else {
    518          surf_index = src_reg(this, glsl_type::uint_type);
    519          emit(ADD(dst_reg(surf_index), get_nir_src(instr->src[1], 1),
    520                   brw_imm_ud(prog_data->base.binding_table.ssbo_start)));
    521          surf_index = emit_uniformize(surf_index);
    522 
    523          brw_mark_surface_used(&prog_data->base,
    524                                prog_data->base.binding_table.ssbo_start +
    525                                nir->info->num_ssbos - 1);
    526       }
    527 
    528       /* Offset */
    529       src_reg offset_reg;
    530       nir_const_value *const_offset = nir_src_as_const_value(instr->src[2]);
    531       if (const_offset) {
    532          offset_reg = brw_imm_ud(const_offset->u32[0]);
    533       } else {
    534          offset_reg = get_nir_src(instr->src[2], 1);
    535       }
    536 
    537       /* Value */
    538       src_reg val_reg = get_nir_src(instr->src[0], BRW_REGISTER_TYPE_F, 4);
    539 
    540       /* Writemask */
    541       unsigned write_mask = instr->const_index[0];
    542 
    543       /* IvyBridge does not have a native SIMD4x2 untyped write message so untyped
    544        * writes will use SIMD8 mode. In order to hide this and keep symmetry across
    545        * typed and untyped messages and across hardware platforms, the
    546        * current implementation of the untyped messages will transparently convert
    547        * the SIMD4x2 payload into an equivalent SIMD8 payload by transposing it
    548        * and enabling only channel X on the SEND instruction.
    549        *
    550        * The above, works well for full vector writes, but not for partial writes
    551        * where we want to write some channels and not others, like when we have
    552        * code such as v.xyw = vec3(1,2,4). Because the untyped write messages are
    553        * quite restrictive with regards to the channel enables we can configure in
    554        * the message descriptor (not all combinations are allowed) we cannot simply
    555        * implement these scenarios with a single message while keeping the
    556        * aforementioned symmetry in the implementation. For now we de decided that
    557        * it is better to keep the symmetry to reduce complexity, so in situations
    558        * such as the one described we end up emitting two untyped write messages
    559        * (one for xy and another for w).
    560        *
    561        * The code below packs consecutive channels into a single write message,
    562        * detects gaps in the vector write and if needed, sends a second message
    563        * with the remaining channels. If in the future we decide that we want to
    564        * emit a single message at the expense of losing the symmetry in the
    565        * implementation we can:
    566        *
    567        * 1) For IvyBridge: Only use the red channel of the untyped write SIMD8
    568        *    message payload. In this mode we can write up to 8 offsets and dwords
    569        *    to the red channel only (for the two vec4s in the SIMD4x2 execution)
    570        *    and select which of the 8 channels carry data to write by setting the
    571        *    appropriate writemask in the dst register of the SEND instruction.
    572        *    It would require to write a new generator opcode specifically for
    573        *    IvyBridge since we would need to prepare a SIMD8 payload that could
    574        *    use any channel, not just X.
    575        *
    576        * 2) For Haswell+: Simply send a single write message but set the writemask
    577        *    on the dst of the SEND instruction to select the channels we want to
    578        *    write. It would require to modify the current messages to receive
    579        *    and honor the writemask provided.
    580        */
    581       const vec4_builder bld = vec4_builder(this).at_end()
    582                                .annotate(current_annotation, base_ir);
    583 
    584       unsigned type_slots = nir_src_bit_size(instr->src[0]) / 32;
    585       if (type_slots == 2) {
    586          dst_reg tmp = dst_reg(this, glsl_type::dvec4_type);
    587          shuffle_64bit_data(tmp, retype(val_reg, tmp.type), true);
    588          val_reg = src_reg(retype(tmp, BRW_REGISTER_TYPE_F));
    589       }
    590 
    591       uint8_t swizzle[4] = { 0, 0, 0, 0};
    592       int num_channels = 0;
    593       unsigned skipped_channels = 0;
    594       int num_components = instr->num_components;
    595       for (int i = 0; i < num_components; i++) {
    596          /* Read components Z/W of a dvec from the appropriate place. We will
    597           * also have to adjust the swizzle (we do that with the '% 4' below)
    598           */
    599          if (i == 2 && type_slots == 2)
    600             val_reg = byte_offset(val_reg, REG_SIZE);
    601 
    602          /* Check if this channel needs to be written. If so, record the
    603           * channel we need to take the data from in the swizzle array
    604           */
    605          int component_mask = 1 << i;
    606          int write_test = write_mask & component_mask;
    607          if (write_test) {
    608             /* If we are writing doubles we have to write 2 channels worth of
    609              * of data (64 bits) for each double component.
    610              */
    611             swizzle[num_channels++] = (i * type_slots) % 4;
    612             if (type_slots == 2)
    613                swizzle[num_channels++] = (i * type_slots + 1) % 4;
    614          }
    615 
    616          /* If we don't have to write this channel it means we have a gap in the
    617           * vector, so write the channels we accumulated until now, if any. Do
    618           * the same if this was the last component in the vector, if we have
    619           * enough channels for a full vec4 write or if we have processed
    620           * components XY of a dvec (since components ZW are not in the same
    621           * SIMD register)
    622           */
    623          if (!write_test || i == num_components - 1 || num_channels == 4 ||
    624              (i == 1 && type_slots == 2)) {
    625             if (num_channels > 0) {
    626                /* We have channels to write, so update the offset we need to
    627                 * write at to skip the channels we skipped, if any.
    628                 */
    629                if (skipped_channels > 0) {
    630                   if (offset_reg.file == IMM) {
    631                      offset_reg.ud += 4 * skipped_channels;
    632                   } else {
    633                      emit(ADD(dst_reg(offset_reg), offset_reg,
    634                               brw_imm_ud(4 * skipped_channels)));
    635                   }
    636                }
    637 
    638                /* Swizzle the data register so we take the data from the channels
    639                 * we need to write and send the write message. This will write
    640                 * num_channels consecutive dwords starting at offset.
    641                 */
    642                val_reg.swizzle =
    643                   BRW_SWIZZLE4(swizzle[0], swizzle[1], swizzle[2], swizzle[3]);
    644                emit_untyped_write(bld, surf_index, offset_reg, val_reg,
    645                                   1 /* dims */, num_channels /* size */,
    646                                   BRW_PREDICATE_NONE);
    647 
    648                /* If we have to do a second write we will have to update the
    649                 * offset so that we jump over the channels we have just written
    650                 * now.
    651                 */
    652                skipped_channels = num_channels;
    653 
    654                /* Restart the count for the next write message */
    655                num_channels = 0;
    656             }
    657 
    658             /* If we didn't write the channel, increase skipped count */
    659             if (!write_test)
    660                skipped_channels += type_slots;
    661          }
    662       }
    663 
    664       break;
    665    }
    666 
    667    case nir_intrinsic_load_ssbo: {
    668       assert(devinfo->gen >= 7);
    669 
    670       nir_const_value *const_uniform_block =
    671          nir_src_as_const_value(instr->src[0]);
    672 
    673       src_reg surf_index;
    674       if (const_uniform_block) {
    675          unsigned index = prog_data->base.binding_table.ssbo_start +
    676                           const_uniform_block->u32[0];
    677          surf_index = brw_imm_ud(index);
    678 
    679          brw_mark_surface_used(&prog_data->base, index);
    680       } else {
    681          surf_index = src_reg(this, glsl_type::uint_type);
    682          emit(ADD(dst_reg(surf_index), get_nir_src(instr->src[0], 1),
    683                   brw_imm_ud(prog_data->base.binding_table.ssbo_start)));
    684          surf_index = emit_uniformize(surf_index);
    685 
    686          /* Assume this may touch any UBO. It would be nice to provide
    687           * a tighter bound, but the array information is already lowered away.
    688           */
    689          brw_mark_surface_used(&prog_data->base,
    690                                prog_data->base.binding_table.ssbo_start +
    691                                nir->info->num_ssbos - 1);
    692       }
    693 
    694       src_reg offset_reg;
    695       nir_const_value *const_offset = nir_src_as_const_value(instr->src[1]);
    696       if (const_offset) {
    697          offset_reg = brw_imm_ud(const_offset->u32[0]);
    698       } else {
    699          offset_reg = get_nir_src(instr->src[1], 1);
    700       }
    701 
    702       /* Read the vector */
    703       const vec4_builder bld = vec4_builder(this).at_end()
    704          .annotate(current_annotation, base_ir);
    705 
    706       src_reg read_result;
    707       dst_reg dest = get_nir_dest(instr->dest);
    708       if (type_sz(dest.type) < 8) {
    709          read_result = emit_untyped_read(bld, surf_index, offset_reg,
    710                                          1 /* dims */, 4 /* size*/,
    711                                          BRW_PREDICATE_NONE);
    712       } else {
    713          src_reg shuffled = src_reg(this, glsl_type::dvec4_type);
    714 
    715          src_reg temp;
    716          temp = emit_untyped_read(bld, surf_index, offset_reg,
    717                                   1 /* dims */, 4 /* size*/,
    718                                   BRW_PREDICATE_NONE);
    719          emit(MOV(dst_reg(retype(shuffled, temp.type)), temp));
    720 
    721          if (offset_reg.file == IMM)
    722             offset_reg.ud += 16;
    723          else
    724             emit(ADD(dst_reg(offset_reg), offset_reg, brw_imm_ud(16)));
    725 
    726          temp = emit_untyped_read(bld, surf_index, offset_reg,
    727                                   1 /* dims */, 4 /* size*/,
    728                                   BRW_PREDICATE_NONE);
    729          emit(MOV(dst_reg(retype(byte_offset(shuffled, REG_SIZE), temp.type)),
    730                   temp));
    731 
    732          read_result = src_reg(this, glsl_type::dvec4_type);
    733          shuffle_64bit_data(dst_reg(read_result), shuffled, false);
    734       }
    735 
    736       read_result.type = dest.type;
    737       read_result.swizzle = brw_swizzle_for_size(instr->num_components);
    738       emit(MOV(dest, read_result));
    739       break;
    740    }
    741 
    742    case nir_intrinsic_ssbo_atomic_add:
    743       nir_emit_ssbo_atomic(BRW_AOP_ADD, instr);
    744       break;
    745    case nir_intrinsic_ssbo_atomic_imin:
    746       nir_emit_ssbo_atomic(BRW_AOP_IMIN, instr);
    747       break;
    748    case nir_intrinsic_ssbo_atomic_umin:
    749       nir_emit_ssbo_atomic(BRW_AOP_UMIN, instr);
    750       break;
    751    case nir_intrinsic_ssbo_atomic_imax:
    752       nir_emit_ssbo_atomic(BRW_AOP_IMAX, instr);
    753       break;
    754    case nir_intrinsic_ssbo_atomic_umax:
    755       nir_emit_ssbo_atomic(BRW_AOP_UMAX, instr);
    756       break;
    757    case nir_intrinsic_ssbo_atomic_and:
    758       nir_emit_ssbo_atomic(BRW_AOP_AND, instr);
    759       break;
    760    case nir_intrinsic_ssbo_atomic_or:
    761       nir_emit_ssbo_atomic(BRW_AOP_OR, instr);
    762       break;
    763    case nir_intrinsic_ssbo_atomic_xor:
    764       nir_emit_ssbo_atomic(BRW_AOP_XOR, instr);
    765       break;
    766    case nir_intrinsic_ssbo_atomic_exchange:
    767       nir_emit_ssbo_atomic(BRW_AOP_MOV, instr);
    768       break;
    769    case nir_intrinsic_ssbo_atomic_comp_swap:
    770       nir_emit_ssbo_atomic(BRW_AOP_CMPWR, instr);
    771       break;
    772 
    773    case nir_intrinsic_load_vertex_id:
    774       unreachable("should be lowered by lower_vertex_id()");
    775 
    776    case nir_intrinsic_load_vertex_id_zero_base:
    777    case nir_intrinsic_load_base_vertex:
    778    case nir_intrinsic_load_instance_id:
    779    case nir_intrinsic_load_base_instance:
    780    case nir_intrinsic_load_draw_id:
    781    case nir_intrinsic_load_invocation_id: {
    782       gl_system_value sv = nir_system_value_from_intrinsic(instr->intrinsic);
    783       src_reg val = src_reg(nir_system_values[sv]);
    784       assert(val.file != BAD_FILE);
    785       dest = get_nir_dest(instr->dest, val.type);
    786       emit(MOV(dest, val));
    787       break;
    788    }
    789 
    790    case nir_intrinsic_load_uniform: {
    791       /* Offsets are in bytes but they should always be multiples of 4 */
    792       assert(nir_intrinsic_base(instr) % 4 == 0);
    793 
    794       dest = get_nir_dest(instr->dest);
    795 
    796       src = src_reg(dst_reg(UNIFORM, nir_intrinsic_base(instr) / 16));
    797       src.type = dest.type;
    798 
    799       /* Uniforms don't actually have to be vec4 aligned.  In the case that
    800        * it isn't, we have to use a swizzle to shift things around.  They
    801        * do still have the std140 alignment requirement that vec2's have to
    802        * be vec2-aligned and vec3's and vec4's have to be vec4-aligned.
    803        *
    804        * The swizzle also works in the indirect case as the generator adds
    805        * the swizzle to the offset for us.
    806        */
    807       unsigned shift = (nir_intrinsic_base(instr) % 16) / 4;
    808       assert(shift + instr->num_components <= 4);
    809 
    810       nir_const_value *const_offset = nir_src_as_const_value(instr->src[0]);
    811       if (const_offset) {
    812          /* Offsets are in bytes but they should always be multiples of 4 */
    813          assert(const_offset->u32[0] % 4 == 0);
    814 
    815          unsigned offset = const_offset->u32[0] + shift * 4;
    816          src.offset = ROUND_DOWN_TO(offset, 16);
    817          shift = (offset % 16) / 4;
    818          src.swizzle += BRW_SWIZZLE4(shift, shift, shift, shift);
    819 
    820          emit(MOV(dest, src));
    821       } else {
    822          src.swizzle += BRW_SWIZZLE4(shift, shift, shift, shift);
    823 
    824          src_reg indirect = get_nir_src(instr->src[0], BRW_REGISTER_TYPE_UD, 1);
    825 
    826          /* MOV_INDIRECT is going to stomp the whole thing anyway */
    827          dest.writemask = WRITEMASK_XYZW;
    828 
    829          emit(SHADER_OPCODE_MOV_INDIRECT, dest, src,
    830               indirect, brw_imm_ud(instr->const_index[1]));
    831       }
    832       break;
    833    }
    834 
    835    case nir_intrinsic_atomic_counter_read:
    836    case nir_intrinsic_atomic_counter_inc:
    837    case nir_intrinsic_atomic_counter_dec: {
    838       unsigned surf_index = prog_data->base.binding_table.abo_start +
    839          (unsigned) instr->const_index[0];
    840       const vec4_builder bld =
    841          vec4_builder(this).at_end().annotate(current_annotation, base_ir);
    842 
    843       /* Get some metadata from the image intrinsic. */
    844       const nir_intrinsic_info *info = &nir_intrinsic_infos[instr->intrinsic];
    845 
    846       /* Get the arguments of the atomic intrinsic. */
    847       src_reg offset = get_nir_src(instr->src[0], nir_type_int32,
    848                                    instr->num_components);
    849       const src_reg surface = brw_imm_ud(surf_index);
    850       const src_reg src0 = (info->num_srcs >= 2
    851                            ? get_nir_src(instr->src[1]) : src_reg());
    852       const src_reg src1 = (info->num_srcs >= 3
    853                            ? get_nir_src(instr->src[2]) : src_reg());
    854 
    855       src_reg tmp;
    856 
    857       dest = get_nir_dest(instr->dest);
    858 
    859       if (instr->intrinsic == nir_intrinsic_atomic_counter_read) {
    860          tmp = emit_untyped_read(bld, surface, offset, 1, 1);
    861       } else {
    862          tmp = emit_untyped_atomic(bld, surface, offset,
    863                                    src0, src1,
    864                                    1, 1,
    865                                    get_atomic_counter_op(instr->intrinsic));
    866       }
    867 
    868       bld.MOV(retype(dest, tmp.type), tmp);
    869       brw_mark_surface_used(stage_prog_data, surf_index);
    870       break;
    871    }
    872 
    873    case nir_intrinsic_load_ubo: {
    874       nir_const_value *const_block_index = nir_src_as_const_value(instr->src[0]);
    875       src_reg surf_index;
    876 
    877       dest = get_nir_dest(instr->dest);
    878 
    879       if (const_block_index) {
    880          /* The block index is a constant, so just emit the binding table entry
    881           * as an immediate.
    882           */
    883          const unsigned index = prog_data->base.binding_table.ubo_start +
    884                                 const_block_index->u32[0];
    885          surf_index = brw_imm_ud(index);
    886          brw_mark_surface_used(&prog_data->base, index);
    887       } else {
    888          /* The block index is not a constant. Evaluate the index expression
    889           * per-channel and add the base UBO index; we have to select a value
    890           * from any live channel.
    891           */
    892          surf_index = src_reg(this, glsl_type::uint_type);
    893          emit(ADD(dst_reg(surf_index), get_nir_src(instr->src[0], nir_type_int32,
    894                                                    instr->num_components),
    895                   brw_imm_ud(prog_data->base.binding_table.ubo_start)));
    896          surf_index = emit_uniformize(surf_index);
    897 
    898          /* Assume this may touch any UBO. It would be nice to provide
    899           * a tighter bound, but the array information is already lowered away.
    900           */
    901          brw_mark_surface_used(&prog_data->base,
    902                                prog_data->base.binding_table.ubo_start +
    903                                nir->info->num_ubos - 1);
    904       }
    905 
    906       src_reg offset_reg;
    907       nir_const_value *const_offset = nir_src_as_const_value(instr->src[1]);
    908       if (const_offset) {
    909          offset_reg = brw_imm_ud(const_offset->u32[0] & ~15);
    910       } else {
    911          offset_reg = get_nir_src(instr->src[1], nir_type_uint32, 1);
    912       }
    913 
    914       src_reg packed_consts;
    915       if (nir_dest_bit_size(instr->dest) == 32) {
    916          packed_consts = src_reg(this, glsl_type::vec4_type);
    917          emit_pull_constant_load_reg(dst_reg(packed_consts),
    918                                      surf_index,
    919                                      offset_reg,
    920                                      NULL, NULL /* before_block/inst */);
    921       } else {
    922          src_reg temp = src_reg(this, glsl_type::dvec4_type);
    923          src_reg temp_float = retype(temp, BRW_REGISTER_TYPE_F);
    924 
    925          emit_pull_constant_load_reg(dst_reg(temp_float),
    926                                      surf_index, offset_reg, NULL, NULL);
    927          if (offset_reg.file == IMM)
    928             offset_reg.ud += 16;
    929          else
    930             emit(ADD(dst_reg(offset_reg), offset_reg, brw_imm_ud(16u)));
    931          emit_pull_constant_load_reg(dst_reg(byte_offset(temp_float, REG_SIZE)),
    932                                      surf_index, offset_reg, NULL, NULL);
    933 
    934          packed_consts = src_reg(this, glsl_type::dvec4_type);
    935          shuffle_64bit_data(dst_reg(packed_consts), temp, false);
    936       }
    937 
    938       packed_consts.swizzle = brw_swizzle_for_size(instr->num_components);
    939       if (const_offset) {
    940          unsigned type_size = type_sz(dest.type);
    941          packed_consts.swizzle +=
    942             BRW_SWIZZLE4(const_offset->u32[0] % 16 / type_size,
    943                          const_offset->u32[0] % 16 / type_size,
    944                          const_offset->u32[0] % 16 / type_size,
    945                          const_offset->u32[0] % 16 / type_size);
    946       }
    947 
    948       emit(MOV(dest, retype(packed_consts, dest.type)));
    949 
    950       break;
    951    }
    952 
    953    case nir_intrinsic_memory_barrier: {
    954       const vec4_builder bld =
    955          vec4_builder(this).at_end().annotate(current_annotation, base_ir);
    956       const dst_reg tmp = bld.vgrf(BRW_REGISTER_TYPE_UD, 2);
    957       bld.emit(SHADER_OPCODE_MEMORY_FENCE, tmp)
    958          ->size_written = 2 * REG_SIZE;
    959       break;
    960    }
    961 
    962    case nir_intrinsic_shader_clock: {
    963       /* We cannot do anything if there is an event, so ignore it for now */
    964       const src_reg shader_clock = get_timestamp();
    965       const enum brw_reg_type type = brw_type_for_base_type(glsl_type::uvec2_type);
    966 
    967       dest = get_nir_dest(instr->dest, type);
    968       emit(MOV(dest, shader_clock));
    969       break;
    970    }
    971 
    972    default:
    973       unreachable("Unknown intrinsic");
    974    }
    975 }
    976 
    977 void
    978 vec4_visitor::nir_emit_ssbo_atomic(int op, nir_intrinsic_instr *instr)
    979 {
    980    dst_reg dest;
    981    if (nir_intrinsic_infos[instr->intrinsic].has_dest)
    982       dest = get_nir_dest(instr->dest);
    983 
    984    src_reg surface;
    985    nir_const_value *const_surface = nir_src_as_const_value(instr->src[0]);
    986    if (const_surface) {
    987       unsigned surf_index = prog_data->base.binding_table.ssbo_start +
    988                             const_surface->u32[0];
    989       surface = brw_imm_ud(surf_index);
    990       brw_mark_surface_used(&prog_data->base, surf_index);
    991    } else {
    992       surface = src_reg(this, glsl_type::uint_type);
    993       emit(ADD(dst_reg(surface), get_nir_src(instr->src[0]),
    994                brw_imm_ud(prog_data->base.binding_table.ssbo_start)));
    995 
    996       /* Assume this may touch any UBO. This is the same we do for other
    997        * UBO/SSBO accesses with non-constant surface.
    998        */
    999       brw_mark_surface_used(&prog_data->base,
   1000                             prog_data->base.binding_table.ssbo_start +
   1001                             nir->info->num_ssbos - 1);
   1002    }
   1003 
   1004    src_reg offset = get_nir_src(instr->src[1], 1);
   1005    src_reg data1 = get_nir_src(instr->src[2], 1);
   1006    src_reg data2;
   1007    if (op == BRW_AOP_CMPWR)
   1008       data2 = get_nir_src(instr->src[3], 1);
   1009 
   1010    /* Emit the actual atomic operation operation */
   1011    const vec4_builder bld =
   1012       vec4_builder(this).at_end().annotate(current_annotation, base_ir);
   1013 
   1014    src_reg atomic_result = emit_untyped_atomic(bld, surface, offset,
   1015                                                data1, data2,
   1016                                                1 /* dims */, 1 /* rsize */,
   1017                                                op,
   1018                                                BRW_PREDICATE_NONE);
   1019    dest.type = atomic_result.type;
   1020    bld.MOV(dest, atomic_result);
   1021 }
   1022 
   1023 static unsigned
   1024 brw_swizzle_for_nir_swizzle(uint8_t swizzle[4])
   1025 {
   1026    return BRW_SWIZZLE4(swizzle[0], swizzle[1], swizzle[2], swizzle[3]);
   1027 }
   1028 
   1029 static enum brw_conditional_mod
   1030 brw_conditional_for_nir_comparison(nir_op op)
   1031 {
   1032    switch (op) {
   1033    case nir_op_flt:
   1034    case nir_op_ilt:
   1035    case nir_op_ult:
   1036       return BRW_CONDITIONAL_L;
   1037 
   1038    case nir_op_fge:
   1039    case nir_op_ige:
   1040    case nir_op_uge:
   1041       return BRW_CONDITIONAL_GE;
   1042 
   1043    case nir_op_feq:
   1044    case nir_op_ieq:
   1045    case nir_op_ball_fequal2:
   1046    case nir_op_ball_iequal2:
   1047    case nir_op_ball_fequal3:
   1048    case nir_op_ball_iequal3:
   1049    case nir_op_ball_fequal4:
   1050    case nir_op_ball_iequal4:
   1051       return BRW_CONDITIONAL_Z;
   1052 
   1053    case nir_op_fne:
   1054    case nir_op_ine:
   1055    case nir_op_bany_fnequal2:
   1056    case nir_op_bany_inequal2:
   1057    case nir_op_bany_fnequal3:
   1058    case nir_op_bany_inequal3:
   1059    case nir_op_bany_fnequal4:
   1060    case nir_op_bany_inequal4:
   1061       return BRW_CONDITIONAL_NZ;
   1062 
   1063    default:
   1064       unreachable("not reached: bad operation for comparison");
   1065    }
   1066 }
   1067 
   1068 bool
   1069 vec4_visitor::optimize_predicate(nir_alu_instr *instr,
   1070                                  enum brw_predicate *predicate)
   1071 {
   1072    if (!instr->src[0].src.is_ssa ||
   1073        instr->src[0].src.ssa->parent_instr->type != nir_instr_type_alu)
   1074       return false;
   1075 
   1076    nir_alu_instr *cmp_instr =
   1077       nir_instr_as_alu(instr->src[0].src.ssa->parent_instr);
   1078 
   1079    switch (cmp_instr->op) {
   1080    case nir_op_bany_fnequal2:
   1081    case nir_op_bany_inequal2:
   1082    case nir_op_bany_fnequal3:
   1083    case nir_op_bany_inequal3:
   1084    case nir_op_bany_fnequal4:
   1085    case nir_op_bany_inequal4:
   1086       *predicate = BRW_PREDICATE_ALIGN16_ANY4H;
   1087       break;
   1088    case nir_op_ball_fequal2:
   1089    case nir_op_ball_iequal2:
   1090    case nir_op_ball_fequal3:
   1091    case nir_op_ball_iequal3:
   1092    case nir_op_ball_fequal4:
   1093    case nir_op_ball_iequal4:
   1094       *predicate = BRW_PREDICATE_ALIGN16_ALL4H;
   1095       break;
   1096    default:
   1097       return false;
   1098    }
   1099 
   1100    unsigned size_swizzle =
   1101       brw_swizzle_for_size(nir_op_infos[cmp_instr->op].input_sizes[0]);
   1102 
   1103    src_reg op[2];
   1104    assert(nir_op_infos[cmp_instr->op].num_inputs == 2);
   1105    for (unsigned i = 0; i < 2; i++) {
   1106       nir_alu_type type = nir_op_infos[cmp_instr->op].input_types[i];
   1107       unsigned bit_size = nir_src_bit_size(cmp_instr->src[i].src);
   1108       type = (nir_alu_type) (((unsigned) type) | bit_size);
   1109       op[i] = get_nir_src(cmp_instr->src[i].src, type, 4);
   1110       unsigned base_swizzle =
   1111          brw_swizzle_for_nir_swizzle(cmp_instr->src[i].swizzle);
   1112       op[i].swizzle = brw_compose_swizzle(size_swizzle, base_swizzle);
   1113       op[i].abs = cmp_instr->src[i].abs;
   1114       op[i].negate = cmp_instr->src[i].negate;
   1115    }
   1116 
   1117    emit(CMP(dst_null_d(), op[0], op[1],
   1118             brw_conditional_for_nir_comparison(cmp_instr->op)));
   1119 
   1120    return true;
   1121 }
   1122 
   1123 static void
   1124 emit_find_msb_using_lzd(const vec4_builder &bld,
   1125                         const dst_reg &dst,
   1126                         const src_reg &src,
   1127                         bool is_signed)
   1128 {
   1129    vec4_instruction *inst;
   1130    src_reg temp = src;
   1131 
   1132    if (is_signed) {
   1133       /* LZD of an absolute value source almost always does the right
   1134        * thing.  There are two problem values:
   1135        *
   1136        * * 0x80000000.  Since abs(0x80000000) == 0x80000000, LZD returns
   1137        *   0.  However, findMSB(int(0x80000000)) == 30.
   1138        *
   1139        * * 0xffffffff.  Since abs(0xffffffff) == 1, LZD returns
   1140        *   31.  Section 8.8 (Integer Functions) of the GLSL 4.50 spec says:
   1141        *
   1142        *    For a value of zero or negative one, -1 will be returned.
   1143        *
   1144        * * Negative powers of two.  LZD(abs(-(1<<x))) returns x, but
   1145        *   findMSB(-(1<<x)) should return x-1.
   1146        *
   1147        * For all negative number cases, including 0x80000000 and
   1148        * 0xffffffff, the correct value is obtained from LZD if instead of
   1149        * negating the (already negative) value the logical-not is used.  A
   1150        * conditonal logical-not can be achieved in two instructions.
   1151        */
   1152       temp = src_reg(bld.vgrf(BRW_REGISTER_TYPE_D));
   1153 
   1154       bld.ASR(dst_reg(temp), src, brw_imm_d(31));
   1155       bld.XOR(dst_reg(temp), temp, src);
   1156    }
   1157 
   1158    bld.LZD(retype(dst, BRW_REGISTER_TYPE_UD),
   1159            retype(temp, BRW_REGISTER_TYPE_UD));
   1160 
   1161    /* LZD counts from the MSB side, while GLSL's findMSB() wants the count
   1162     * from the LSB side. Subtract the result from 31 to convert the MSB count
   1163     * into an LSB count.  If no bits are set, LZD will return 32.  31-32 = -1,
   1164     * which is exactly what findMSB() is supposed to return.
   1165     */
   1166    inst = bld.ADD(dst, retype(src_reg(dst), BRW_REGISTER_TYPE_D),
   1167                   brw_imm_d(31));
   1168    inst->src[0].negate = true;
   1169 }
   1170 
   1171 void
   1172 vec4_visitor::emit_conversion_from_double(dst_reg dst, src_reg src,
   1173                                           bool saturate,
   1174                                           brw_reg_type single_type)
   1175 {
   1176    /* BDW PRM vol 15 - workarounds:
   1177     * DF->f format conversion for Align16 has wrong emask calculation when
   1178     * source is immediate.
   1179     */
   1180    if (devinfo->gen == 8 && single_type == BRW_REGISTER_TYPE_F &&
   1181        src.file == BRW_IMMEDIATE_VALUE) {
   1182       vec4_instruction *inst = emit(MOV(dst, brw_imm_f(src.df)));
   1183       inst->saturate = saturate;
   1184       return;
   1185    }
   1186 
   1187    dst_reg temp = dst_reg(this, glsl_type::dvec4_type);
   1188    emit(MOV(temp, src));
   1189 
   1190    dst_reg temp2 = dst_reg(this, glsl_type::dvec4_type);
   1191    temp2 = retype(temp2, single_type);
   1192    emit(VEC4_OPCODE_FROM_DOUBLE, temp2, src_reg(temp))
   1193       ->size_written = 2 * REG_SIZE;
   1194 
   1195    vec4_instruction *inst = emit(MOV(dst, src_reg(temp2)));
   1196    inst->saturate = saturate;
   1197 }
   1198 
   1199 void
   1200 vec4_visitor::emit_conversion_to_double(dst_reg dst, src_reg src,
   1201                                         bool saturate,
   1202                                         brw_reg_type single_type)
   1203 {
   1204    dst_reg tmp_dst = dst_reg(src_reg(this, glsl_type::dvec4_type));
   1205    src_reg tmp_src = retype(src_reg(this, glsl_type::vec4_type), single_type);
   1206    emit(MOV(dst_reg(tmp_src), retype(src, single_type)));
   1207    emit(VEC4_OPCODE_TO_DOUBLE, tmp_dst, tmp_src);
   1208    vec4_instruction *inst = emit(MOV(dst, src_reg(tmp_dst)));
   1209    inst->saturate = saturate;
   1210 }
   1211 
   1212 src_reg
   1213 vec4_visitor::setup_imm_df(double v)
   1214 {
   1215    assert(devinfo->gen >= 7);
   1216 
   1217    if (devinfo->gen >= 8)
   1218       return brw_imm_df(v);
   1219 
   1220    /* gen7.5 does not support DF immediates straighforward but the DIM
   1221     * instruction allows to set the 64-bit immediate value.
   1222     */
   1223    if (devinfo->is_haswell) {
   1224       dst_reg dst = retype(dst_reg(VGRF, alloc.allocate(2)), BRW_REGISTER_TYPE_DF);
   1225       emit(DIM(dst, brw_imm_df(v)))->force_writemask_all = true;
   1226       return swizzle(src_reg(retype(dst, BRW_REGISTER_TYPE_DF)), BRW_SWIZZLE_XXXX);
   1227    }
   1228 
   1229    /* gen7 does not support DF immediates */
   1230    union {
   1231       double d;
   1232       struct {
   1233          uint32_t i1;
   1234          uint32_t i2;
   1235       };
   1236    } di;
   1237 
   1238    di.d = v;
   1239 
   1240    /* Write the low 32-bit of the constant to the X:UD channel and the
   1241     * high 32-bit to the Y:UD channel to build the constant in a VGRF.
   1242     * We have to do this twice (offset 0 and offset 1), since a DF VGRF takes
   1243     * two SIMD8 registers in SIMD4x2 execution. Finally, return a swizzle
   1244     * XXXX so any access to the VGRF only reads the constant data in these
   1245     * channels.
   1246     */
   1247    const dst_reg tmp =
   1248       retype(dst_reg(VGRF, alloc.allocate(2)), BRW_REGISTER_TYPE_UD);
   1249    for (int n = 0; n < 2; n++) {
   1250       emit(MOV(writemask(offset(tmp, 8, n), WRITEMASK_X), brw_imm_ud(di.i1)))
   1251          ->force_writemask_all = true;
   1252       emit(MOV(writemask(offset(tmp, 8, n), WRITEMASK_Y), brw_imm_ud(di.i2)))
   1253          ->force_writemask_all = true;
   1254    }
   1255 
   1256    return swizzle(src_reg(retype(tmp, BRW_REGISTER_TYPE_DF)), BRW_SWIZZLE_XXXX);
   1257 }
   1258 
   1259 void
   1260 vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
   1261 {
   1262    vec4_instruction *inst;
   1263 
   1264    nir_alu_type dst_type = (nir_alu_type) (nir_op_infos[instr->op].output_type |
   1265                                            nir_dest_bit_size(instr->dest.dest));
   1266    dst_reg dst = get_nir_dest(instr->dest.dest, dst_type);
   1267    dst.writemask = instr->dest.write_mask;
   1268 
   1269    src_reg op[4];
   1270    for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
   1271       nir_alu_type src_type = (nir_alu_type)
   1272          (nir_op_infos[instr->op].input_types[i] |
   1273           nir_src_bit_size(instr->src[i].src));
   1274       op[i] = get_nir_src(instr->src[i].src, src_type, 4);
   1275       op[i].swizzle = brw_swizzle_for_nir_swizzle(instr->src[i].swizzle);
   1276       op[i].abs = instr->src[i].abs;
   1277       op[i].negate = instr->src[i].negate;
   1278    }
   1279 
   1280    switch (instr->op) {
   1281    case nir_op_imov:
   1282    case nir_op_fmov:
   1283       inst = emit(MOV(dst, op[0]));
   1284       inst->saturate = instr->dest.saturate;
   1285       break;
   1286 
   1287    case nir_op_vec2:
   1288    case nir_op_vec3:
   1289    case nir_op_vec4:
   1290       unreachable("not reached: should be handled by lower_vec_to_movs()");
   1291 
   1292    case nir_op_i2f:
   1293    case nir_op_u2f:
   1294       inst = emit(MOV(dst, op[0]));
   1295       inst->saturate = instr->dest.saturate;
   1296       break;
   1297 
   1298    case nir_op_f2i:
   1299    case nir_op_f2u:
   1300       inst = emit(MOV(dst, op[0]));
   1301       break;
   1302 
   1303    case nir_op_d2f:
   1304       emit_conversion_from_double(dst, op[0], instr->dest.saturate,
   1305                                   BRW_REGISTER_TYPE_F);
   1306       break;
   1307 
   1308    case nir_op_f2d:
   1309       emit_conversion_to_double(dst, op[0], instr->dest.saturate,
   1310                                 BRW_REGISTER_TYPE_F);
   1311       break;
   1312 
   1313    case nir_op_d2i:
   1314    case nir_op_d2u:
   1315       emit_conversion_from_double(dst, op[0], instr->dest.saturate,
   1316                                   instr->op == nir_op_d2i ? BRW_REGISTER_TYPE_D :
   1317                                                             BRW_REGISTER_TYPE_UD);
   1318       break;
   1319 
   1320    case nir_op_i2d:
   1321    case nir_op_u2d:
   1322       emit_conversion_to_double(dst, op[0], instr->dest.saturate,
   1323                                 instr->op == nir_op_i2d ? BRW_REGISTER_TYPE_D :
   1324                                                           BRW_REGISTER_TYPE_UD);
   1325       break;
   1326 
   1327    case nir_op_iadd:
   1328       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1329    case nir_op_fadd:
   1330       inst = emit(ADD(dst, op[0], op[1]));
   1331       inst->saturate = instr->dest.saturate;
   1332       break;
   1333 
   1334    case nir_op_fmul:
   1335       inst = emit(MUL(dst, op[0], op[1]));
   1336       inst->saturate = instr->dest.saturate;
   1337       break;
   1338 
   1339    case nir_op_imul: {
   1340       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1341       if (devinfo->gen < 8) {
   1342          nir_const_value *value0 = nir_src_as_const_value(instr->src[0].src);
   1343          nir_const_value *value1 = nir_src_as_const_value(instr->src[1].src);
   1344 
   1345          /* For integer multiplication, the MUL uses the low 16 bits of one of
   1346           * the operands (src0 through SNB, src1 on IVB and later). The MACH
   1347           * accumulates in the contribution of the upper 16 bits of that
   1348           * operand. If we can determine that one of the args is in the low
   1349           * 16 bits, though, we can just emit a single MUL.
   1350           */
   1351          if (value0 && value0->u32[0] < (1 << 16)) {
   1352             if (devinfo->gen < 7)
   1353                emit(MUL(dst, op[0], op[1]));
   1354             else
   1355                emit(MUL(dst, op[1], op[0]));
   1356          } else if (value1 && value1->u32[0] < (1 << 16)) {
   1357             if (devinfo->gen < 7)
   1358                emit(MUL(dst, op[1], op[0]));
   1359             else
   1360                emit(MUL(dst, op[0], op[1]));
   1361          } else {
   1362             struct brw_reg acc = retype(brw_acc_reg(8), dst.type);
   1363 
   1364             emit(MUL(acc, op[0], op[1]));
   1365             emit(MACH(dst_null_d(), op[0], op[1]));
   1366             emit(MOV(dst, src_reg(acc)));
   1367          }
   1368       } else {
   1369 	 emit(MUL(dst, op[0], op[1]));
   1370       }
   1371       break;
   1372    }
   1373 
   1374    case nir_op_imul_high:
   1375    case nir_op_umul_high: {
   1376       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1377       struct brw_reg acc = retype(brw_acc_reg(8), dst.type);
   1378 
   1379       if (devinfo->gen >= 8)
   1380          emit(MUL(acc, op[0], retype(op[1], BRW_REGISTER_TYPE_UW)));
   1381       else
   1382          emit(MUL(acc, op[0], op[1]));
   1383 
   1384       emit(MACH(dst, op[0], op[1]));
   1385       break;
   1386    }
   1387 
   1388    case nir_op_frcp:
   1389       inst = emit_math(SHADER_OPCODE_RCP, dst, op[0]);
   1390       inst->saturate = instr->dest.saturate;
   1391       break;
   1392 
   1393    case nir_op_fexp2:
   1394       inst = emit_math(SHADER_OPCODE_EXP2, dst, op[0]);
   1395       inst->saturate = instr->dest.saturate;
   1396       break;
   1397 
   1398    case nir_op_flog2:
   1399       inst = emit_math(SHADER_OPCODE_LOG2, dst, op[0]);
   1400       inst->saturate = instr->dest.saturate;
   1401       break;
   1402 
   1403    case nir_op_fsin:
   1404       inst = emit_math(SHADER_OPCODE_SIN, dst, op[0]);
   1405       inst->saturate = instr->dest.saturate;
   1406       break;
   1407 
   1408    case nir_op_fcos:
   1409       inst = emit_math(SHADER_OPCODE_COS, dst, op[0]);
   1410       inst->saturate = instr->dest.saturate;
   1411       break;
   1412 
   1413    case nir_op_idiv:
   1414    case nir_op_udiv:
   1415       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1416       emit_math(SHADER_OPCODE_INT_QUOTIENT, dst, op[0], op[1]);
   1417       break;
   1418 
   1419    case nir_op_umod:
   1420    case nir_op_irem:
   1421       /* According to the sign table for INT DIV in the Ivy Bridge PRM, it
   1422        * appears that our hardware just does the right thing for signed
   1423        * remainder.
   1424        */
   1425       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1426       emit_math(SHADER_OPCODE_INT_REMAINDER, dst, op[0], op[1]);
   1427       break;
   1428 
   1429    case nir_op_imod: {
   1430       /* Get a regular C-style remainder.  If a % b == 0, set the predicate. */
   1431       inst = emit_math(SHADER_OPCODE_INT_REMAINDER, dst, op[0], op[1]);
   1432 
   1433       /* Math instructions don't support conditional mod */
   1434       inst = emit(MOV(dst_null_d(), src_reg(dst)));
   1435       inst->conditional_mod = BRW_CONDITIONAL_NZ;
   1436 
   1437       /* Now, we need to determine if signs of the sources are different.
   1438        * When we XOR the sources, the top bit is 0 if they are the same and 1
   1439        * if they are different.  We can then use a conditional modifier to
   1440        * turn that into a predicate.  This leads us to an XOR.l instruction.
   1441        *
   1442        * Technically, according to the PRM, you're not allowed to use .l on a
   1443        * XOR instruction.  However, emperical experiments and Curro's reading
   1444        * of the simulator source both indicate that it's safe.
   1445        */
   1446       src_reg tmp = src_reg(this, glsl_type::ivec4_type);
   1447       inst = emit(XOR(dst_reg(tmp), op[0], op[1]));
   1448       inst->predicate = BRW_PREDICATE_NORMAL;
   1449       inst->conditional_mod = BRW_CONDITIONAL_L;
   1450 
   1451       /* If the result of the initial remainder operation is non-zero and the
   1452        * two sources have different signs, add in a copy of op[1] to get the
   1453        * final integer modulus value.
   1454        */
   1455       inst = emit(ADD(dst, src_reg(dst), op[1]));
   1456       inst->predicate = BRW_PREDICATE_NORMAL;
   1457       break;
   1458    }
   1459 
   1460    case nir_op_ldexp:
   1461       unreachable("not reached: should be handled by ldexp_to_arith()");
   1462 
   1463    case nir_op_fsqrt:
   1464       inst = emit_math(SHADER_OPCODE_SQRT, dst, op[0]);
   1465       inst->saturate = instr->dest.saturate;
   1466       break;
   1467 
   1468    case nir_op_frsq:
   1469       inst = emit_math(SHADER_OPCODE_RSQ, dst, op[0]);
   1470       inst->saturate = instr->dest.saturate;
   1471       break;
   1472 
   1473    case nir_op_fpow:
   1474       inst = emit_math(SHADER_OPCODE_POW, dst, op[0], op[1]);
   1475       inst->saturate = instr->dest.saturate;
   1476       break;
   1477 
   1478    case nir_op_uadd_carry: {
   1479       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1480       struct brw_reg acc = retype(brw_acc_reg(8), BRW_REGISTER_TYPE_UD);
   1481 
   1482       emit(ADDC(dst_null_ud(), op[0], op[1]));
   1483       emit(MOV(dst, src_reg(acc)));
   1484       break;
   1485    }
   1486 
   1487    case nir_op_usub_borrow: {
   1488       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1489       struct brw_reg acc = retype(brw_acc_reg(8), BRW_REGISTER_TYPE_UD);
   1490 
   1491       emit(SUBB(dst_null_ud(), op[0], op[1]));
   1492       emit(MOV(dst, src_reg(acc)));
   1493       break;
   1494    }
   1495 
   1496    case nir_op_ftrunc:
   1497       inst = emit(RNDZ(dst, op[0]));
   1498       inst->saturate = instr->dest.saturate;
   1499       break;
   1500 
   1501    case nir_op_fceil: {
   1502       src_reg tmp = src_reg(this, glsl_type::float_type);
   1503       tmp.swizzle =
   1504          brw_swizzle_for_size(instr->src[0].src.is_ssa ?
   1505                               instr->src[0].src.ssa->num_components :
   1506                               instr->src[0].src.reg.reg->num_components);
   1507 
   1508       op[0].negate = !op[0].negate;
   1509       emit(RNDD(dst_reg(tmp), op[0]));
   1510       tmp.negate = true;
   1511       inst = emit(MOV(dst, tmp));
   1512       inst->saturate = instr->dest.saturate;
   1513       break;
   1514    }
   1515 
   1516    case nir_op_ffloor:
   1517       inst = emit(RNDD(dst, op[0]));
   1518       inst->saturate = instr->dest.saturate;
   1519       break;
   1520 
   1521    case nir_op_ffract:
   1522       inst = emit(FRC(dst, op[0]));
   1523       inst->saturate = instr->dest.saturate;
   1524       break;
   1525 
   1526    case nir_op_fround_even:
   1527       inst = emit(RNDE(dst, op[0]));
   1528       inst->saturate = instr->dest.saturate;
   1529       break;
   1530 
   1531    case nir_op_fquantize2f16: {
   1532       /* See also vec4_visitor::emit_pack_half_2x16() */
   1533       src_reg tmp16 = src_reg(this, glsl_type::uvec4_type);
   1534       src_reg tmp32 = src_reg(this, glsl_type::vec4_type);
   1535       src_reg zero = src_reg(this, glsl_type::vec4_type);
   1536 
   1537       /* Check for denormal */
   1538       src_reg abs_src0 = op[0];
   1539       abs_src0.abs = true;
   1540       emit(CMP(dst_null_f(), abs_src0, brw_imm_f(ldexpf(1.0, -14)),
   1541                BRW_CONDITIONAL_L));
   1542       /* Get the appropriately signed zero */
   1543       emit(AND(retype(dst_reg(zero), BRW_REGISTER_TYPE_UD),
   1544                retype(op[0], BRW_REGISTER_TYPE_UD),
   1545                brw_imm_ud(0x80000000)));
   1546       /* Do the actual F32 -> F16 -> F32 conversion */
   1547       emit(F32TO16(dst_reg(tmp16), op[0]));
   1548       emit(F16TO32(dst_reg(tmp32), tmp16));
   1549       /* Select that or zero based on normal status */
   1550       inst = emit(BRW_OPCODE_SEL, dst, zero, tmp32);
   1551       inst->predicate = BRW_PREDICATE_NORMAL;
   1552       inst->saturate = instr->dest.saturate;
   1553       break;
   1554    }
   1555 
   1556    case nir_op_imin:
   1557    case nir_op_umin:
   1558       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1559    case nir_op_fmin:
   1560       inst = emit_minmax(BRW_CONDITIONAL_L, dst, op[0], op[1]);
   1561       inst->saturate = instr->dest.saturate;
   1562       break;
   1563 
   1564    case nir_op_imax:
   1565    case nir_op_umax:
   1566       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1567    case nir_op_fmax:
   1568       inst = emit_minmax(BRW_CONDITIONAL_GE, dst, op[0], op[1]);
   1569       inst->saturate = instr->dest.saturate;
   1570       break;
   1571 
   1572    case nir_op_fddx:
   1573    case nir_op_fddx_coarse:
   1574    case nir_op_fddx_fine:
   1575    case nir_op_fddy:
   1576    case nir_op_fddy_coarse:
   1577    case nir_op_fddy_fine:
   1578       unreachable("derivatives are not valid in vertex shaders");
   1579 
   1580    case nir_op_ilt:
   1581    case nir_op_ult:
   1582    case nir_op_ige:
   1583    case nir_op_uge:
   1584    case nir_op_ieq:
   1585    case nir_op_ine:
   1586       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1587       /* Fallthrough */
   1588    case nir_op_flt:
   1589    case nir_op_fge:
   1590    case nir_op_feq:
   1591    case nir_op_fne: {
   1592       enum brw_conditional_mod conditional_mod =
   1593          brw_conditional_for_nir_comparison(instr->op);
   1594 
   1595       if (nir_src_bit_size(instr->src[0].src) < 64) {
   1596          emit(CMP(dst, op[0], op[1], conditional_mod));
   1597       } else {
   1598          /* Produce a 32-bit boolean result from the DF comparison by selecting
   1599           * only the low 32-bit in each DF produced. Do this in a temporary
   1600           * so we can then move from there to the result using align16 again
   1601           * to honor the original writemask.
   1602           */
   1603          dst_reg temp = dst_reg(this, glsl_type::dvec4_type);
   1604          emit(CMP(temp, op[0], op[1], conditional_mod));
   1605          dst_reg result = dst_reg(this, glsl_type::bvec4_type);
   1606          emit(VEC4_OPCODE_PICK_LOW_32BIT, result, src_reg(temp));
   1607          emit(MOV(dst, src_reg(result)));
   1608       }
   1609       break;
   1610    }
   1611 
   1612    case nir_op_ball_iequal2:
   1613    case nir_op_ball_iequal3:
   1614    case nir_op_ball_iequal4:
   1615       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1616       /* Fallthrough */
   1617    case nir_op_ball_fequal2:
   1618    case nir_op_ball_fequal3:
   1619    case nir_op_ball_fequal4: {
   1620       unsigned swiz =
   1621          brw_swizzle_for_size(nir_op_infos[instr->op].input_sizes[0]);
   1622 
   1623       emit(CMP(dst_null_d(), swizzle(op[0], swiz), swizzle(op[1], swiz),
   1624                brw_conditional_for_nir_comparison(instr->op)));
   1625       emit(MOV(dst, brw_imm_d(0)));
   1626       inst = emit(MOV(dst, brw_imm_d(~0)));
   1627       inst->predicate = BRW_PREDICATE_ALIGN16_ALL4H;
   1628       break;
   1629    }
   1630 
   1631    case nir_op_bany_inequal2:
   1632    case nir_op_bany_inequal3:
   1633    case nir_op_bany_inequal4:
   1634       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1635       /* Fallthrough */
   1636    case nir_op_bany_fnequal2:
   1637    case nir_op_bany_fnequal3:
   1638    case nir_op_bany_fnequal4: {
   1639       unsigned swiz =
   1640          brw_swizzle_for_size(nir_op_infos[instr->op].input_sizes[0]);
   1641 
   1642       emit(CMP(dst_null_d(), swizzle(op[0], swiz), swizzle(op[1], swiz),
   1643                brw_conditional_for_nir_comparison(instr->op)));
   1644 
   1645       emit(MOV(dst, brw_imm_d(0)));
   1646       inst = emit(MOV(dst, brw_imm_d(~0)));
   1647       inst->predicate = BRW_PREDICATE_ALIGN16_ANY4H;
   1648       break;
   1649    }
   1650 
   1651    case nir_op_inot:
   1652       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1653       if (devinfo->gen >= 8) {
   1654          op[0] = resolve_source_modifiers(op[0]);
   1655       }
   1656       emit(NOT(dst, op[0]));
   1657       break;
   1658 
   1659    case nir_op_ixor:
   1660       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1661       if (devinfo->gen >= 8) {
   1662          op[0] = resolve_source_modifiers(op[0]);
   1663          op[1] = resolve_source_modifiers(op[1]);
   1664       }
   1665       emit(XOR(dst, op[0], op[1]));
   1666       break;
   1667 
   1668    case nir_op_ior:
   1669       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1670       if (devinfo->gen >= 8) {
   1671          op[0] = resolve_source_modifiers(op[0]);
   1672          op[1] = resolve_source_modifiers(op[1]);
   1673       }
   1674       emit(OR(dst, op[0], op[1]));
   1675       break;
   1676 
   1677    case nir_op_iand:
   1678       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1679       if (devinfo->gen >= 8) {
   1680          op[0] = resolve_source_modifiers(op[0]);
   1681          op[1] = resolve_source_modifiers(op[1]);
   1682       }
   1683       emit(AND(dst, op[0], op[1]));
   1684       break;
   1685 
   1686    case nir_op_b2i:
   1687    case nir_op_b2f:
   1688       emit(MOV(dst, negate(op[0])));
   1689       break;
   1690 
   1691    case nir_op_f2b:
   1692       emit(CMP(dst, op[0], brw_imm_f(0.0f), BRW_CONDITIONAL_NZ));
   1693       break;
   1694 
   1695    case nir_op_d2b: {
   1696       /* We use a MOV with conditional_mod to check if the provided value is
   1697        * 0.0. We want this to flush denormalized numbers to zero, so we set a
   1698        * source modifier on the source operand to trigger this, as source
   1699        * modifiers don't affect the result of the testing against 0.0.
   1700        */
   1701       src_reg value = op[0];
   1702       value.abs = true;
   1703       vec4_instruction *inst = emit(MOV(dst_null_df(), value));
   1704       inst->conditional_mod = BRW_CONDITIONAL_NZ;
   1705 
   1706       src_reg one = src_reg(this, glsl_type::ivec4_type);
   1707       emit(MOV(dst_reg(one), brw_imm_d(~0)));
   1708       inst = emit(BRW_OPCODE_SEL, dst, one, brw_imm_d(0));
   1709       inst->predicate = BRW_PREDICATE_NORMAL;
   1710       break;
   1711    }
   1712 
   1713    case nir_op_i2b:
   1714       emit(CMP(dst, op[0], brw_imm_d(0), BRW_CONDITIONAL_NZ));
   1715       break;
   1716 
   1717    case nir_op_fnoise1_1:
   1718    case nir_op_fnoise1_2:
   1719    case nir_op_fnoise1_3:
   1720    case nir_op_fnoise1_4:
   1721    case nir_op_fnoise2_1:
   1722    case nir_op_fnoise2_2:
   1723    case nir_op_fnoise2_3:
   1724    case nir_op_fnoise2_4:
   1725    case nir_op_fnoise3_1:
   1726    case nir_op_fnoise3_2:
   1727    case nir_op_fnoise3_3:
   1728    case nir_op_fnoise3_4:
   1729    case nir_op_fnoise4_1:
   1730    case nir_op_fnoise4_2:
   1731    case nir_op_fnoise4_3:
   1732    case nir_op_fnoise4_4:
   1733       unreachable("not reached: should be handled by lower_noise");
   1734 
   1735    case nir_op_unpack_half_2x16_split_x:
   1736    case nir_op_unpack_half_2x16_split_y:
   1737    case nir_op_pack_half_2x16_split:
   1738       unreachable("not reached: should not occur in vertex shader");
   1739 
   1740    case nir_op_unpack_snorm_2x16:
   1741    case nir_op_unpack_unorm_2x16:
   1742    case nir_op_pack_snorm_2x16:
   1743    case nir_op_pack_unorm_2x16:
   1744       unreachable("not reached: should be handled by lower_packing_builtins");
   1745 
   1746    case nir_op_pack_uvec4_to_uint:
   1747       unreachable("not reached");
   1748 
   1749    case nir_op_pack_uvec2_to_uint: {
   1750       dst_reg tmp1 = dst_reg(this, glsl_type::uint_type);
   1751       tmp1.writemask = WRITEMASK_X;
   1752       op[0].swizzle = BRW_SWIZZLE_YYYY;
   1753       emit(SHL(tmp1, op[0], src_reg(brw_imm_ud(16u))));
   1754 
   1755       dst_reg tmp2 = dst_reg(this, glsl_type::uint_type);
   1756       tmp2.writemask = WRITEMASK_X;
   1757       op[0].swizzle = BRW_SWIZZLE_XXXX;
   1758       emit(AND(tmp2, op[0], src_reg(brw_imm_ud(0xffffu))));
   1759 
   1760       emit(OR(dst, src_reg(tmp1), src_reg(tmp2)));
   1761       break;
   1762    }
   1763 
   1764    case nir_op_pack_double_2x32_split: {
   1765       dst_reg result = dst_reg(this, glsl_type::dvec4_type);
   1766       dst_reg tmp = dst_reg(this, glsl_type::uvec4_type);
   1767       emit(MOV(tmp, retype(op[0], BRW_REGISTER_TYPE_UD)));
   1768       emit(VEC4_OPCODE_SET_LOW_32BIT, result, src_reg(tmp));
   1769       emit(MOV(tmp, retype(op[1], BRW_REGISTER_TYPE_UD)));
   1770       emit(VEC4_OPCODE_SET_HIGH_32BIT, result, src_reg(tmp));
   1771       emit(MOV(dst, src_reg(result)));
   1772       break;
   1773    }
   1774 
   1775    case nir_op_unpack_double_2x32_split_x:
   1776    case nir_op_unpack_double_2x32_split_y: {
   1777       enum opcode oper = (instr->op == nir_op_unpack_double_2x32_split_x) ?
   1778          VEC4_OPCODE_PICK_LOW_32BIT : VEC4_OPCODE_PICK_HIGH_32BIT;
   1779       dst_reg tmp = dst_reg(this, glsl_type::dvec4_type);
   1780       emit(MOV(tmp, op[0]));
   1781       dst_reg tmp2 = dst_reg(this, glsl_type::uvec4_type);
   1782       emit(oper, tmp2, src_reg(tmp));
   1783       emit(MOV(dst, src_reg(tmp2)));
   1784       break;
   1785    }
   1786 
   1787    case nir_op_unpack_half_2x16:
   1788       /* As NIR does not guarantee that we have a correct swizzle outside the
   1789        * boundaries of a vector, and the implementation of emit_unpack_half_2x16
   1790        * uses the source operand in an operation with WRITEMASK_Y while our
   1791        * source operand has only size 1, it accessed incorrect data producing
   1792        * regressions in Piglit. We repeat the swizzle of the first component on the
   1793        * rest of components to avoid regressions. In the vec4_visitor IR code path
   1794        * this is not needed because the operand has already the correct swizzle.
   1795        */
   1796       op[0].swizzle = brw_compose_swizzle(BRW_SWIZZLE_XXXX, op[0].swizzle);
   1797       emit_unpack_half_2x16(dst, op[0]);
   1798       break;
   1799 
   1800    case nir_op_pack_half_2x16:
   1801       emit_pack_half_2x16(dst, op[0]);
   1802       break;
   1803 
   1804    case nir_op_unpack_unorm_4x8:
   1805       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1806       emit_unpack_unorm_4x8(dst, op[0]);
   1807       break;
   1808 
   1809    case nir_op_pack_unorm_4x8:
   1810       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1811       emit_pack_unorm_4x8(dst, op[0]);
   1812       break;
   1813 
   1814    case nir_op_unpack_snorm_4x8:
   1815       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1816       emit_unpack_snorm_4x8(dst, op[0]);
   1817       break;
   1818 
   1819    case nir_op_pack_snorm_4x8:
   1820       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1821       emit_pack_snorm_4x8(dst, op[0]);
   1822       break;
   1823 
   1824    case nir_op_bitfield_reverse:
   1825       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1826       emit(BFREV(dst, op[0]));
   1827       break;
   1828 
   1829    case nir_op_bit_count:
   1830       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1831       emit(CBIT(dst, op[0]));
   1832       break;
   1833 
   1834    case nir_op_ufind_msb:
   1835       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1836       emit_find_msb_using_lzd(vec4_builder(this).at_end(), dst, op[0], false);
   1837       break;
   1838 
   1839    case nir_op_ifind_msb: {
   1840       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1841       vec4_builder bld = vec4_builder(this).at_end();
   1842       src_reg src(dst);
   1843 
   1844       if (devinfo->gen < 7) {
   1845          emit_find_msb_using_lzd(bld, dst, op[0], true);
   1846       } else {
   1847          emit(FBH(retype(dst, BRW_REGISTER_TYPE_UD), op[0]));
   1848 
   1849          /* FBH counts from the MSB side, while GLSL's findMSB() wants the
   1850           * count from the LSB side. If FBH didn't return an error
   1851           * (0xFFFFFFFF), then subtract the result from 31 to convert the MSB
   1852           * count into an LSB count.
   1853           */
   1854          bld.CMP(dst_null_d(), src, brw_imm_d(-1), BRW_CONDITIONAL_NZ);
   1855 
   1856          inst = bld.ADD(dst, src, brw_imm_d(31));
   1857          inst->predicate = BRW_PREDICATE_NORMAL;
   1858          inst->src[0].negate = true;
   1859       }
   1860       break;
   1861    }
   1862 
   1863    case nir_op_find_lsb: {
   1864       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1865       vec4_builder bld = vec4_builder(this).at_end();
   1866 
   1867       if (devinfo->gen < 7) {
   1868          dst_reg temp = bld.vgrf(BRW_REGISTER_TYPE_D);
   1869 
   1870          /* (x & -x) generates a value that consists of only the LSB of x.
   1871           * For all powers of 2, findMSB(y) == findLSB(y).
   1872           */
   1873          src_reg src = src_reg(retype(op[0], BRW_REGISTER_TYPE_D));
   1874          src_reg negated_src = src;
   1875 
   1876          /* One must be negated, and the other must be non-negated.  It
   1877           * doesn't matter which is which.
   1878           */
   1879          negated_src.negate = true;
   1880          src.negate = false;
   1881 
   1882          bld.AND(temp, src, negated_src);
   1883          emit_find_msb_using_lzd(bld, dst, src_reg(temp), false);
   1884       } else {
   1885          bld.FBL(dst, op[0]);
   1886       }
   1887       break;
   1888    }
   1889 
   1890    case nir_op_ubitfield_extract:
   1891    case nir_op_ibitfield_extract:
   1892       unreachable("should have been lowered");
   1893    case nir_op_ubfe:
   1894    case nir_op_ibfe:
   1895       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1896       op[0] = fix_3src_operand(op[0]);
   1897       op[1] = fix_3src_operand(op[1]);
   1898       op[2] = fix_3src_operand(op[2]);
   1899 
   1900       emit(BFE(dst, op[2], op[1], op[0]));
   1901       break;
   1902 
   1903    case nir_op_bfm:
   1904       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1905       emit(BFI1(dst, op[0], op[1]));
   1906       break;
   1907 
   1908    case nir_op_bfi:
   1909       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1910       op[0] = fix_3src_operand(op[0]);
   1911       op[1] = fix_3src_operand(op[1]);
   1912       op[2] = fix_3src_operand(op[2]);
   1913 
   1914       emit(BFI2(dst, op[0], op[1], op[2]));
   1915       break;
   1916 
   1917    case nir_op_bitfield_insert:
   1918       unreachable("not reached: should have been lowered");
   1919 
   1920    case nir_op_fsign:
   1921       if (type_sz(op[0].type) < 8) {
   1922          /* AND(val, 0x80000000) gives the sign bit.
   1923           *
   1924           * Predicated OR ORs 1.0 (0x3f800000) with the sign bit if val is not
   1925           * zero.
   1926           */
   1927          emit(CMP(dst_null_f(), op[0], brw_imm_f(0.0f), BRW_CONDITIONAL_NZ));
   1928 
   1929          op[0].type = BRW_REGISTER_TYPE_UD;
   1930          dst.type = BRW_REGISTER_TYPE_UD;
   1931          emit(AND(dst, op[0], brw_imm_ud(0x80000000u)));
   1932 
   1933          inst = emit(OR(dst, src_reg(dst), brw_imm_ud(0x3f800000u)));
   1934          inst->predicate = BRW_PREDICATE_NORMAL;
   1935          dst.type = BRW_REGISTER_TYPE_F;
   1936 
   1937          if (instr->dest.saturate) {
   1938             inst = emit(MOV(dst, src_reg(dst)));
   1939             inst->saturate = true;
   1940          }
   1941       } else {
   1942          /* For doubles we do the same but we need to consider:
   1943           *
   1944           * - We use a MOV with conditional_mod instead of a CMP so that we can
   1945           *   skip loading a 0.0 immediate. We use a source modifier on the
   1946           *   source of the MOV so that we flush denormalized values to 0.
   1947           *   Since we want to compare against 0, this won't alter the result.
   1948           * - We need to extract the high 32-bit of each DF where the sign
   1949           *   is stored.
   1950           * - We need to produce a DF result.
   1951           */
   1952 
   1953          /* Check for zero */
   1954          src_reg value = op[0];
   1955          value.abs = true;
   1956          inst = emit(MOV(dst_null_df(), value));
   1957          inst->conditional_mod = BRW_CONDITIONAL_NZ;
   1958 
   1959          /* AND each high 32-bit channel with 0x80000000u */
   1960          dst_reg tmp = dst_reg(this, glsl_type::uvec4_type);
   1961          emit(VEC4_OPCODE_PICK_HIGH_32BIT, tmp, op[0]);
   1962          emit(AND(tmp, src_reg(tmp), brw_imm_ud(0x80000000u)));
   1963 
   1964          /* Add 1.0 to each channel, predicated to skip the cases where the
   1965           * channel's value was 0
   1966           */
   1967          inst = emit(OR(tmp, src_reg(tmp), brw_imm_ud(0x3f800000u)));
   1968          inst->predicate = BRW_PREDICATE_NORMAL;
   1969 
   1970          /* Now convert the result from float to double */
   1971          emit_conversion_to_double(dst, src_reg(tmp), instr->dest.saturate,
   1972                                    BRW_REGISTER_TYPE_F);
   1973       }
   1974       break;
   1975 
   1976    case nir_op_isign:
   1977       /*  ASR(val, 31) -> negative val generates 0xffffffff (signed -1).
   1978        *               -> non-negative val generates 0x00000000.
   1979        *  Predicated OR sets 1 if val is positive.
   1980        */
   1981       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1982       emit(CMP(dst_null_d(), op[0], brw_imm_d(0), BRW_CONDITIONAL_G));
   1983       emit(ASR(dst, op[0], brw_imm_d(31)));
   1984       inst = emit(OR(dst, src_reg(dst), brw_imm_d(1)));
   1985       inst->predicate = BRW_PREDICATE_NORMAL;
   1986       break;
   1987 
   1988    case nir_op_ishl:
   1989       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1990       emit(SHL(dst, op[0], op[1]));
   1991       break;
   1992 
   1993    case nir_op_ishr:
   1994       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   1995       emit(ASR(dst, op[0], op[1]));
   1996       break;
   1997 
   1998    case nir_op_ushr:
   1999       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   2000       emit(SHR(dst, op[0], op[1]));
   2001       break;
   2002 
   2003    case nir_op_ffma:
   2004       if (type_sz(dst.type) == 8) {
   2005          dst_reg mul_dst = dst_reg(this, glsl_type::dvec4_type);
   2006          emit(MUL(mul_dst, op[1], op[0]));
   2007          inst = emit(ADD(dst, src_reg(mul_dst), op[2]));
   2008          inst->saturate = instr->dest.saturate;
   2009       } else {
   2010          op[0] = fix_3src_operand(op[0]);
   2011          op[1] = fix_3src_operand(op[1]);
   2012          op[2] = fix_3src_operand(op[2]);
   2013 
   2014          inst = emit(MAD(dst, op[2], op[1], op[0]));
   2015          inst->saturate = instr->dest.saturate;
   2016       }
   2017       break;
   2018 
   2019    case nir_op_flrp:
   2020       inst = emit_lrp(dst, op[0], op[1], op[2]);
   2021       inst->saturate = instr->dest.saturate;
   2022       break;
   2023 
   2024    case nir_op_bcsel:
   2025       enum brw_predicate predicate;
   2026       if (!optimize_predicate(instr, &predicate)) {
   2027          emit(CMP(dst_null_d(), op[0], brw_imm_d(0), BRW_CONDITIONAL_NZ));
   2028          switch (dst.writemask) {
   2029          case WRITEMASK_X:
   2030             predicate = BRW_PREDICATE_ALIGN16_REPLICATE_X;
   2031             break;
   2032          case WRITEMASK_Y:
   2033             predicate = BRW_PREDICATE_ALIGN16_REPLICATE_Y;
   2034             break;
   2035          case WRITEMASK_Z:
   2036             predicate = BRW_PREDICATE_ALIGN16_REPLICATE_Z;
   2037             break;
   2038          case WRITEMASK_W:
   2039             predicate = BRW_PREDICATE_ALIGN16_REPLICATE_W;
   2040             break;
   2041          default:
   2042             predicate = BRW_PREDICATE_NORMAL;
   2043             break;
   2044          }
   2045       }
   2046       inst = emit(BRW_OPCODE_SEL, dst, op[1], op[2]);
   2047       inst->predicate = predicate;
   2048       break;
   2049 
   2050    case nir_op_fdot_replicated2:
   2051       inst = emit(BRW_OPCODE_DP2, dst, op[0], op[1]);
   2052       inst->saturate = instr->dest.saturate;
   2053       break;
   2054 
   2055    case nir_op_fdot_replicated3:
   2056       inst = emit(BRW_OPCODE_DP3, dst, op[0], op[1]);
   2057       inst->saturate = instr->dest.saturate;
   2058       break;
   2059 
   2060    case nir_op_fdot_replicated4:
   2061       inst = emit(BRW_OPCODE_DP4, dst, op[0], op[1]);
   2062       inst->saturate = instr->dest.saturate;
   2063       break;
   2064 
   2065    case nir_op_fdph_replicated:
   2066       inst = emit(BRW_OPCODE_DPH, dst, op[0], op[1]);
   2067       inst->saturate = instr->dest.saturate;
   2068       break;
   2069 
   2070    case nir_op_iabs:
   2071    case nir_op_ineg:
   2072       assert(nir_dest_bit_size(instr->dest.dest) < 64);
   2073    case nir_op_fabs:
   2074    case nir_op_fneg:
   2075    case nir_op_fsat:
   2076       unreachable("not reached: should be lowered by lower_source mods");
   2077 
   2078    case nir_op_fdiv:
   2079       unreachable("not reached: should be lowered by DIV_TO_MUL_RCP in the compiler");
   2080 
   2081    case nir_op_fmod:
   2082       unreachable("not reached: should be lowered by MOD_TO_FLOOR in the compiler");
   2083 
   2084    case nir_op_fsub:
   2085    case nir_op_isub:
   2086       unreachable("not reached: should be handled by ir_sub_to_add_neg");
   2087 
   2088    default:
   2089       unreachable("Unimplemented ALU operation");
   2090    }
   2091 
   2092    /* If we need to do a boolean resolve, replace the result with -(x & 1)
   2093     * to sign extend the low bit to 0/~0
   2094     */
   2095    if (devinfo->gen <= 5 &&
   2096        (instr->instr.pass_flags & BRW_NIR_BOOLEAN_MASK) ==
   2097        BRW_NIR_BOOLEAN_NEEDS_RESOLVE) {
   2098       dst_reg masked = dst_reg(this, glsl_type::int_type);
   2099       masked.writemask = dst.writemask;
   2100       emit(AND(masked, src_reg(dst), brw_imm_d(1)));
   2101       src_reg masked_neg = src_reg(masked);
   2102       masked_neg.negate = true;
   2103       emit(MOV(retype(dst, BRW_REGISTER_TYPE_D), masked_neg));
   2104    }
   2105 }
   2106 
   2107 void
   2108 vec4_visitor::nir_emit_jump(nir_jump_instr *instr)
   2109 {
   2110    switch (instr->type) {
   2111    case nir_jump_break:
   2112       emit(BRW_OPCODE_BREAK);
   2113       break;
   2114 
   2115    case nir_jump_continue:
   2116       emit(BRW_OPCODE_CONTINUE);
   2117       break;
   2118 
   2119    case nir_jump_return:
   2120       /* fall through */
   2121    default:
   2122       unreachable("unknown jump");
   2123    }
   2124 }
   2125 
   2126 enum ir_texture_opcode
   2127 ir_texture_opcode_for_nir_texop(nir_texop texop)
   2128 {
   2129    enum ir_texture_opcode op;
   2130 
   2131    switch (texop) {
   2132    case nir_texop_lod: op = ir_lod; break;
   2133    case nir_texop_query_levels: op = ir_query_levels; break;
   2134    case nir_texop_texture_samples: op = ir_texture_samples; break;
   2135    case nir_texop_tex: op = ir_tex; break;
   2136    case nir_texop_tg4: op = ir_tg4; break;
   2137    case nir_texop_txb: op = ir_txb; break;
   2138    case nir_texop_txd: op = ir_txd; break;
   2139    case nir_texop_txf: op = ir_txf; break;
   2140    case nir_texop_txf_ms: op = ir_txf_ms; break;
   2141    case nir_texop_txl: op = ir_txl; break;
   2142    case nir_texop_txs: op = ir_txs; break;
   2143    case nir_texop_samples_identical: op = ir_samples_identical; break;
   2144    default:
   2145       unreachable("unknown texture opcode");
   2146    }
   2147 
   2148    return op;
   2149 }
   2150 const glsl_type *
   2151 glsl_type_for_nir_alu_type(nir_alu_type alu_type,
   2152                            unsigned components)
   2153 {
   2154    return glsl_type::get_instance(brw_glsl_base_type_for_nir_type(alu_type),
   2155                                   components, 1);
   2156 }
   2157 
   2158 void
   2159 vec4_visitor::nir_emit_texture(nir_tex_instr *instr)
   2160 {
   2161    unsigned texture = instr->texture_index;
   2162    unsigned sampler = instr->sampler_index;
   2163    src_reg texture_reg = brw_imm_ud(texture);
   2164    src_reg sampler_reg = brw_imm_ud(sampler);
   2165    src_reg coordinate;
   2166    const glsl_type *coord_type = NULL;
   2167    src_reg shadow_comparator;
   2168    src_reg offset_value;
   2169    src_reg lod, lod2;
   2170    src_reg sample_index;
   2171    src_reg mcs;
   2172 
   2173    const glsl_type *dest_type =
   2174       glsl_type_for_nir_alu_type(instr->dest_type,
   2175                                  nir_tex_instr_dest_size(instr));
   2176    dst_reg dest = get_nir_dest(instr->dest, instr->dest_type);
   2177 
   2178    /* The hardware requires a LOD for buffer textures */
   2179    if (instr->sampler_dim == GLSL_SAMPLER_DIM_BUF)
   2180       lod = brw_imm_d(0);
   2181 
   2182    /* Load the texture operation sources */
   2183    uint32_t constant_offset = 0;
   2184    for (unsigned i = 0; i < instr->num_srcs; i++) {
   2185       switch (instr->src[i].src_type) {
   2186       case nir_tex_src_comparator:
   2187          shadow_comparator = get_nir_src(instr->src[i].src,
   2188                                          BRW_REGISTER_TYPE_F, 1);
   2189          break;
   2190 
   2191       case nir_tex_src_coord: {
   2192          unsigned src_size = nir_tex_instr_src_size(instr, i);
   2193 
   2194          switch (instr->op) {
   2195          case nir_texop_txf:
   2196          case nir_texop_txf_ms:
   2197          case nir_texop_samples_identical:
   2198             coordinate = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D,
   2199                                      src_size);
   2200             coord_type = glsl_type::ivec(src_size);
   2201             break;
   2202 
   2203          default:
   2204             coordinate = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_F,
   2205                                      src_size);
   2206             coord_type = glsl_type::vec(src_size);
   2207             break;
   2208          }
   2209          break;
   2210       }
   2211 
   2212       case nir_tex_src_ddx:
   2213          lod = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_F,
   2214                            nir_tex_instr_src_size(instr, i));
   2215          break;
   2216 
   2217       case nir_tex_src_ddy:
   2218          lod2 = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_F,
   2219                            nir_tex_instr_src_size(instr, i));
   2220          break;
   2221 
   2222       case nir_tex_src_lod:
   2223          switch (instr->op) {
   2224          case nir_texop_txs:
   2225          case nir_texop_txf:
   2226             lod = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D, 1);
   2227             break;
   2228 
   2229          default:
   2230             lod = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_F, 1);
   2231             break;
   2232          }
   2233          break;
   2234 
   2235       case nir_tex_src_ms_index: {
   2236          sample_index = get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D, 1);
   2237          break;
   2238       }
   2239 
   2240       case nir_tex_src_offset: {
   2241          nir_const_value *const_offset =
   2242             nir_src_as_const_value(instr->src[i].src);
   2243          if (!const_offset ||
   2244              !brw_texture_offset(const_offset->i32,
   2245                                  nir_tex_instr_src_size(instr, i),
   2246                                  &constant_offset)) {
   2247             offset_value =
   2248                get_nir_src(instr->src[i].src, BRW_REGISTER_TYPE_D, 2);
   2249          }
   2250          break;
   2251       }
   2252 
   2253       case nir_tex_src_texture_offset: {
   2254          /* The highest texture which may be used by this operation is
   2255           * the last element of the array. Mark it here, because the generator
   2256           * doesn't have enough information to determine the bound.
   2257           */
   2258          uint32_t array_size = instr->texture_array_size;
   2259          uint32_t max_used = texture + array_size - 1;
   2260          if (instr->op == nir_texop_tg4) {
   2261             max_used += prog_data->base.binding_table.gather_texture_start;
   2262          } else {
   2263             max_used += prog_data->base.binding_table.texture_start;
   2264          }
   2265 
   2266          brw_mark_surface_used(&prog_data->base, max_used);
   2267 
   2268          /* Emit code to evaluate the actual indexing expression */
   2269          src_reg src = get_nir_src(instr->src[i].src, 1);
   2270          src_reg temp(this, glsl_type::uint_type);
   2271          emit(ADD(dst_reg(temp), src, brw_imm_ud(texture)));
   2272          texture_reg = emit_uniformize(temp);
   2273          break;
   2274       }
   2275 
   2276       case nir_tex_src_sampler_offset: {
   2277          /* Emit code to evaluate the actual indexing expression */
   2278          src_reg src = get_nir_src(instr->src[i].src, 1);
   2279          src_reg temp(this, glsl_type::uint_type);
   2280          emit(ADD(dst_reg(temp), src, brw_imm_ud(sampler)));
   2281          sampler_reg = emit_uniformize(temp);
   2282          break;
   2283       }
   2284 
   2285       case nir_tex_src_projector:
   2286          unreachable("Should be lowered by do_lower_texture_projection");
   2287 
   2288       case nir_tex_src_bias:
   2289          unreachable("LOD bias is not valid for vertex shaders.\n");
   2290 
   2291       default:
   2292          unreachable("unknown texture source");
   2293       }
   2294    }
   2295 
   2296    if (instr->op == nir_texop_txf_ms ||
   2297        instr->op == nir_texop_samples_identical) {
   2298       assert(coord_type != NULL);
   2299       if (devinfo->gen >= 7 &&
   2300           key_tex->compressed_multisample_layout_mask & (1 << texture)) {
   2301          mcs = emit_mcs_fetch(coord_type, coordinate, texture_reg);
   2302       } else {
   2303          mcs = brw_imm_ud(0u);
   2304       }
   2305    }
   2306 
   2307    /* Stuff the channel select bits in the top of the texture offset */
   2308    if (instr->op == nir_texop_tg4) {
   2309       if (instr->component == 1 &&
   2310           (key_tex->gather_channel_quirk_mask & (1 << texture))) {
   2311          /* gather4 sampler is broken for green channel on RG32F --
   2312           * we must ask for blue instead.
   2313           */
   2314          constant_offset |= 2 << 16;
   2315       } else {
   2316          constant_offset |= instr->component << 16;
   2317       }
   2318    }
   2319 
   2320    ir_texture_opcode op = ir_texture_opcode_for_nir_texop(instr->op);
   2321 
   2322    emit_texture(op, dest, dest_type, coordinate, instr->coord_components,
   2323                 shadow_comparator,
   2324                 lod, lod2, sample_index,
   2325                 constant_offset, offset_value, mcs,
   2326                 texture, texture_reg, sampler_reg);
   2327 }
   2328 
   2329 void
   2330 vec4_visitor::nir_emit_undef(nir_ssa_undef_instr *instr)
   2331 {
   2332    nir_ssa_values[instr->def.index] =
   2333       dst_reg(VGRF, alloc.allocate(DIV_ROUND_UP(instr->def.bit_size, 32)));
   2334 }
   2335 
   2336 /* SIMD4x2 64bit data is stored in register space like this:
   2337  *
   2338  * r0.0:DF  x0 y0 z0 w0
   2339  * r1.0:DF  x1 y1 z1 w1
   2340  *
   2341  * When we need to write data such as this to memory using 32-bit write
   2342  * messages we need to shuffle it in this fashion:
   2343  *
   2344  * r0.0:DF  x0 y0 x1 y1 (to be written at base offset)
   2345  * r0.0:DF  z0 w0 z1 w1 (to be written at base offset + 16)
   2346  *
   2347  * We need to do the inverse operation when we read using 32-bit messages,
   2348  * which we can do by applying the same exact shuffling on the 64-bit data
   2349  * read, only that because the data for each vertex is positioned differently
   2350  * we need to apply different channel enables.
   2351  *
   2352  * This function takes 64bit data and shuffles it as explained above.
   2353  *
   2354  * The @for_write parameter is used to specify if the shuffling is being done
   2355  * for proper SIMD4x2 64-bit data that needs to be shuffled prior to a 32-bit
   2356  * write message (for_write = true), or instead we are doing the inverse
   2357  * operation and we have just read 64-bit data using a 32-bit messages that we
   2358  * need to shuffle to create valid SIMD4x2 64-bit data (for_write = false).
   2359  *
   2360  * If @block and @ref are non-NULL, then the shuffling is done after @ref,
   2361  * otherwise the instructions are emitted normally at the end. The function
   2362  * returns the last instruction inserted.
   2363  *
   2364  * Notice that @src and @dst cannot be the same register.
   2365  */
   2366 vec4_instruction *
   2367 vec4_visitor::shuffle_64bit_data(dst_reg dst, src_reg src, bool for_write,
   2368                                  bblock_t *block, vec4_instruction *ref)
   2369 {
   2370    assert(type_sz(src.type) == 8);
   2371    assert(type_sz(dst.type) == 8);
   2372    assert(!regions_overlap(dst, 2 * REG_SIZE, src, 2 * REG_SIZE));
   2373    assert(!ref == !block);
   2374 
   2375    const vec4_builder bld = !ref ? vec4_builder(this).at_end() :
   2376                                    vec4_builder(this).at(block, ref->next);
   2377 
   2378    /* Resolve swizzle in src */
   2379    vec4_instruction *inst;
   2380    if (src.swizzle != BRW_SWIZZLE_XYZW) {
   2381       dst_reg data = dst_reg(this, glsl_type::dvec4_type);
   2382       inst = bld.MOV(data, src);
   2383       src = src_reg(data);
   2384    }
   2385 
   2386    /* dst+0.XY = src+0.XY */
   2387    inst = bld.group(4, 0).MOV(writemask(dst, WRITEMASK_XY), src);
   2388 
   2389    /* dst+0.ZW = src+1.XY */
   2390    inst = bld.group(4, for_write ? 1 : 0)
   2391              .MOV(writemask(dst, WRITEMASK_ZW),
   2392                   swizzle(byte_offset(src, REG_SIZE), BRW_SWIZZLE_XYXY));
   2393 
   2394    /* dst+1.XY = src+0.ZW */
   2395    inst = bld.group(4, for_write ? 0 : 1)
   2396             .MOV(writemask(byte_offset(dst, REG_SIZE), WRITEMASK_XY),
   2397                  swizzle(src, BRW_SWIZZLE_ZWZW));
   2398 
   2399    /* dst+1.ZW = src+1.ZW */
   2400    inst = bld.group(4, 1)
   2401              .MOV(writemask(byte_offset(dst, REG_SIZE), WRITEMASK_ZW),
   2402                  byte_offset(src, REG_SIZE));
   2403 
   2404    return inst;
   2405 }
   2406 
   2407 }
   2408