intel/fs: Add an UNDEF instruction to avoid excess live ranges

[mesa.git] / src / intel / compiler / brw_fs_generator.cpp

/*
 * Copyright © 2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

/** @file brw_fs_generator.cpp
 *
 * This file supports generating code from the FS LIR to the actual
 * native instructions.
 */

#include "brw_eu.h"
#include "brw_fs.h"
#include "brw_cfg.h"

static enum brw_reg_file
brw_file_from_reg(fs_reg *reg)
{
   switch (reg->file) {
   case ARF:
      return BRW_ARCHITECTURE_REGISTER_FILE;
   case FIXED_GRF:
   case VGRF:
      return BRW_GENERAL_REGISTER_FILE;
   case MRF:
      return BRW_MESSAGE_REGISTER_FILE;
   case IMM:
      return BRW_IMMEDIATE_VALUE;
   case BAD_FILE:
   case ATTR:
   case UNIFORM:
      unreachable("not reached");
   }
   return BRW_ARCHITECTURE_REGISTER_FILE;
}

static struct brw_reg
brw_reg_from_fs_reg(const struct gen_device_info *devinfo, fs_inst *inst,
                    fs_reg *reg, bool compressed)
{
   struct brw_reg brw_reg;

   switch (reg->file) {
   case MRF:
      assert((reg->nr & ~BRW_MRF_COMPR4) < BRW_MAX_MRF(devinfo->gen));
      /* Fallthrough */
   case VGRF:
      if (reg->stride == 0) {
         brw_reg = brw_vec1_reg(brw_file_from_reg(reg), reg->nr, 0);
      } else {
         /* From the Haswell PRM:
          *
          *  "VertStride must be used to cross GRF register boundaries. This
          *   rule implies that elements within a 'Width' cannot cross GRF
          *   boundaries."
          *
          * The maximum width value that could satisfy this restriction is:
          */
         const unsigned reg_width = REG_SIZE / (reg->stride * type_sz(reg->type));

         /* Because the hardware can only split source regions at a whole
          * multiple of width during decompression (i.e. vertically), clamp
          * the value obtained above to the physical execution size of a
          * single decompressed chunk of the instruction:
          */
         const unsigned phys_width = compressed ? inst->exec_size / 2 :
                                     inst->exec_size;

         /* XXX - The equation above is strictly speaking not correct on
          *       hardware that supports unbalanced GRF writes -- On Gen9+
          *       each decompressed chunk of the instruction may have a
          *       different execution size when the number of components
          *       written to each destination GRF is not the same.
          */
         if (reg->stride > 4) {
            assert(reg != &inst->dst);
            assert(reg->stride * type_sz(reg->type) <= REG_SIZE);
            brw_reg = brw_vecn_reg(1, brw_file_from_reg(reg), reg->nr, 0);
            brw_reg = stride(brw_reg, reg->stride, 1, 0);
         } else {
            const unsigned width = MIN2(reg_width, phys_width);
            brw_reg = brw_vecn_reg(width, brw_file_from_reg(reg), reg->nr, 0);
            brw_reg = stride(brw_reg, width * reg->stride, width, reg->stride);
         }

         if (devinfo->gen == 7 && !devinfo->is_haswell) {
            /* From the IvyBridge PRM (EU Changes by Processor Generation, page 13):
             *  "Each DF (Double Float) operand uses an element size of 4 rather
             *   than 8 and all regioning parameters are twice what the values
             *   would be based on the true element size: ExecSize, Width,
             *   HorzStride, and VertStride. Each DF operand uses a pair of
             *   channels and all masking and swizzing should be adjusted
             *   appropriately."
             *
             * From the IvyBridge PRM (Special Requirements for Handling Double
             * Precision Data Types, page 71):
             *  "In Align1 mode, all regioning parameters like stride, execution
             *   size, and width must use the syntax of a pair of packed
             *   floats. The offsets for these data types must be 64-bit
             *   aligned. The execution size and regioning parameters are in terms
             *   of floats."
             *
             * Summarized: when handling DF-typed arguments, ExecSize,
             * VertStride, and Width must be doubled.
             *
             * It applies to BayTrail too.
             */
            if (type_sz(reg->type) == 8) {
               brw_reg.width++;
               if (brw_reg.vstride > 0)
                  brw_reg.vstride++;
               assert(brw_reg.hstride == BRW_HORIZONTAL_STRIDE_1);
            }

            /* When converting from DF->F, we set the destination stride to 2
             * because each d2f conversion implicitly writes 2 floats, being
             * the first one the converted value. IVB/BYT actually writes two
             * F components per SIMD channel, and every other component is
             * filled with garbage.
             */
            if (reg == &inst->dst && get_exec_type_size(inst) == 8 &&
                type_sz(inst->dst.type) < 8) {
               assert(brw_reg.hstride > BRW_HORIZONTAL_STRIDE_1);
               brw_reg.hstride--;
            }
         }
      }

      brw_reg = retype(brw_reg, reg->type);
      brw_reg = byte_offset(brw_reg, reg->offset);
      brw_reg.abs = reg->abs;
      brw_reg.negate = reg->negate;
      break;
   case ARF:
   case FIXED_GRF:
   case IMM:
      assert(reg->offset == 0);
      brw_reg = reg->as_brw_reg();
      break;
   case BAD_FILE:
      /* Probably unused. */
      brw_reg = brw_null_reg();
      break;
   case ATTR:
   case UNIFORM:
      unreachable("not reached");
   }

   /* On HSW+, scalar DF sources can be accessed using the normal <0,1,0>
    * region, but on IVB and BYT DF regions must be programmed in terms of
    * floats. A <0,2,1> region accomplishes this.
    */
   if (devinfo->gen == 7 && !devinfo->is_haswell &&
       type_sz(reg->type) == 8 &&
       brw_reg.vstride == BRW_VERTICAL_STRIDE_0 &&
       brw_reg.width == BRW_WIDTH_1 &&
       brw_reg.hstride == BRW_HORIZONTAL_STRIDE_0) {
      brw_reg.width = BRW_WIDTH_2;
      brw_reg.hstride = BRW_HORIZONTAL_STRIDE_1;
   }

   return brw_reg;
}

fs_generator::fs_generator(const struct brw_compiler *compiler, void *log_data,
                           void *mem_ctx,
                           struct brw_stage_prog_data *prog_data,
                           unsigned promoted_constants,
                           bool runtime_check_aads_emit,
                           gl_shader_stage stage)

   : compiler(compiler), log_data(log_data),
     devinfo(compiler->devinfo),
     prog_data(prog_data),
     promoted_constants(promoted_constants),
     runtime_check_aads_emit(runtime_check_aads_emit), debug_flag(false),
     stage(stage), mem_ctx(mem_ctx)
{
   p = rzalloc(mem_ctx, struct brw_codegen);
   brw_init_codegen(devinfo, p, mem_ctx);

   /* In the FS code generator, we are very careful to ensure that we always
    * set the right execution size so we don't need the EU code to "help" us
    * by trying to infer it.  Sometimes, it infers the wrong thing.
    */
   p->automatic_exec_sizes = false;
}

fs_generator::~fs_generator()
{
}

class ip_record : public exec_node {
public:
   DECLARE_RALLOC_CXX_OPERATORS(ip_record)

   ip_record(int ip)
   {
      this->ip = ip;
   }

   int ip;
};

bool
fs_generator::patch_discard_jumps_to_fb_writes()
{
   if (devinfo->gen < 6 || this->discard_halt_patches.is_empty())
      return false;

   int scale = brw_jump_scale(p->devinfo);

   /* There is a somewhat strange undocumented requirement of using
    * HALT, according to the simulator.  If some channel has HALTed to
    * a particular UIP, then by the end of the program, every channel
    * must have HALTed to that UIP.  Furthermore, the tracking is a
    * stack, so you can't do the final halt of a UIP after starting
    * halting to a new UIP.
    *
    * Symptoms of not emitting this instruction on actual hardware
    * included GPU hangs and sparkly rendering on the piglit discard
    * tests.
    */
   brw_inst *last_halt = gen6_HALT(p);
   brw_inst_set_uip(p->devinfo, last_halt, 1 * scale);
   brw_inst_set_jip(p->devinfo, last_halt, 1 * scale);

   int ip = p->nr_insn;

   foreach_in_list(ip_record, patch_ip, &discard_halt_patches) {
      brw_inst *patch = &p->store[patch_ip->ip];

      assert(brw_inst_opcode(p->devinfo, patch) == BRW_OPCODE_HALT);
      /* HALT takes a half-instruction distance from the pre-incremented IP. */
      brw_inst_set_uip(p->devinfo, patch, (ip - patch_ip->ip) * scale);
   }

   this->discard_halt_patches.make_empty();
   return true;
}

void
fs_generator::generate_send(fs_inst *inst,
                            struct brw_reg dst,
                            struct brw_reg desc,
                            struct brw_reg ex_desc,
                            struct brw_reg payload,
                            struct brw_reg payload2)
{
   const bool dst_is_null = dst.file == BRW_ARCHITECTURE_REGISTER_FILE &&
                            dst.nr == BRW_ARF_NULL;
   const unsigned rlen = dst_is_null ? 0 : inst->size_written / REG_SIZE;

   uint32_t desc_imm = inst->desc |
      brw_message_desc(devinfo, inst->mlen, rlen, inst->header_size);

   uint32_t ex_desc_imm = brw_message_ex_desc(devinfo, inst->ex_mlen);

   if (ex_desc.file != BRW_IMMEDIATE_VALUE || ex_desc.ud || ex_desc_imm) {
      /* If we have any sort of extended descriptor, then we need SENDS.  This
       * also covers the dual-payload case because ex_mlen goes in ex_desc.
       */
      brw_send_indirect_split_message(p, inst->sfid, dst, payload, payload2,
                                      desc, desc_imm, ex_desc, ex_desc_imm,
                                      inst->eot);
      if (inst->check_tdr)
         brw_inst_set_opcode(p->devinfo, brw_last_inst, BRW_OPCODE_SENDSC);
   } else {
      brw_send_indirect_message(p, inst->sfid, dst, payload, desc, desc_imm,
                                   inst->eot);
      if (inst->check_tdr)
         brw_inst_set_opcode(p->devinfo, brw_last_inst, BRW_OPCODE_SENDC);
   }
}

void
fs_generator::fire_fb_write(fs_inst *inst,
                            struct brw_reg payload,
                            struct brw_reg implied_header,
                            GLuint nr)
{
   uint32_t msg_control;

   struct brw_wm_prog_data *prog_data = brw_wm_prog_data(this->prog_data);

   if (devinfo->gen < 6) {
      brw_push_insn_state(p);
      brw_set_default_exec_size(p, BRW_EXECUTE_8);
      brw_set_default_mask_control(p, BRW_MASK_DISABLE);
      brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
      brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
      brw_MOV(p, offset(retype(payload, BRW_REGISTER_TYPE_UD), 1),
              offset(retype(implied_header, BRW_REGISTER_TYPE_UD), 1));
      brw_pop_insn_state(p);
   }

   if (inst->opcode == FS_OPCODE_REP_FB_WRITE) {
      assert(inst->group == 0 && inst->exec_size == 16);
      msg_control = BRW_DATAPORT_RENDER_TARGET_WRITE_SIMD16_SINGLE_SOURCE_REPLICATED;

   } else if (prog_data->dual_src_blend) {
      assert(inst->exec_size == 8);

      if (inst->group % 16 == 0)
         msg_control = BRW_DATAPORT_RENDER_TARGET_WRITE_SIMD8_DUAL_SOURCE_SUBSPAN01;
      else if (inst->group % 16 == 8)
         msg_control = BRW_DATAPORT_RENDER_TARGET_WRITE_SIMD8_DUAL_SOURCE_SUBSPAN23;
      else
         unreachable("Invalid dual-source FB write instruction group");

   } else {
      assert(inst->group == 0 || (inst->group == 16 && inst->exec_size == 16));

      if (inst->exec_size == 16)
         msg_control = BRW_DATAPORT_RENDER_TARGET_WRITE_SIMD16_SINGLE_SOURCE;
      else if (inst->exec_size == 8)
         msg_control = BRW_DATAPORT_RENDER_TARGET_WRITE_SIMD8_SINGLE_SOURCE_SUBSPAN01;
      else
         unreachable("Invalid FB write execution size");
   }

   /* We assume render targets start at 0, because headerless FB write
    * messages set "Render Target Index" to 0.  Using a different binding
    * table index would make it impossible to use headerless messages.
    */
   const uint32_t surf_index = inst->target;

   brw_inst *insn = brw_fb_WRITE(p,
                                 payload,
                                 retype(implied_header, BRW_REGISTER_TYPE_UW),
                                 msg_control,
                                 surf_index,
                                 nr,
                                 0,
                                 inst->eot,
                                 inst->last_rt,
                                 inst->header_size != 0);

   if (devinfo->gen >= 6)
      brw_inst_set_rt_slot_group(devinfo, insn, inst->group / 16);
}

void
fs_generator::generate_fb_write(fs_inst *inst, struct brw_reg payload)
{
   if (devinfo->gen < 8 && !devinfo->is_haswell) {
      brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
      brw_set_default_flag_reg(p, 0, 0);
   }

   const struct brw_reg implied_header =
      devinfo->gen < 6 ? payload : brw_null_reg();

   if (inst->base_mrf >= 0)
      payload = brw_message_reg(inst->base_mrf);

   if (!runtime_check_aads_emit) {
      fire_fb_write(inst, payload, implied_header, inst->mlen);
   } else {
      /* This can only happen in gen < 6 */
      assert(devinfo->gen < 6);

      struct brw_reg v1_null_ud = vec1(retype(brw_null_reg(), BRW_REGISTER_TYPE_UD));

      /* Check runtime bit to detect if we have to send AA data or not */
      brw_push_insn_state(p);
      brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
      brw_set_default_exec_size(p, BRW_EXECUTE_1);
      brw_AND(p,
              v1_null_ud,
              retype(brw_vec1_grf(1, 6), BRW_REGISTER_TYPE_UD),
              brw_imm_ud(1<<26));
      brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_NZ);

      int jmp = brw_JMPI(p, brw_imm_ud(0), BRW_PREDICATE_NORMAL) - p->store;
      brw_pop_insn_state(p);
      {
         /* Don't send AA data */
         fire_fb_write(inst, offset(payload, 1), implied_header, inst->mlen-1);
      }
      brw_land_fwd_jump(p, jmp);
      fire_fb_write(inst, payload, implied_header, inst->mlen);
   }
}

void
fs_generator::generate_fb_read(fs_inst *inst, struct brw_reg dst,
                               struct brw_reg payload)
{
   assert(inst->size_written % REG_SIZE == 0);
   struct brw_wm_prog_data *prog_data = brw_wm_prog_data(this->prog_data);
   /* We assume that render targets start at binding table index 0. */
   const unsigned surf_index = inst->target;

   gen9_fb_READ(p, dst, payload, surf_index,
                inst->header_size, inst->size_written / REG_SIZE,
                prog_data->persample_dispatch);
}

void
fs_generator::generate_mov_indirect(fs_inst *inst,
                                    struct brw_reg dst,
                                    struct brw_reg reg,
                                    struct brw_reg indirect_byte_offset)
{
   assert(indirect_byte_offset.type == BRW_REGISTER_TYPE_UD);
   assert(indirect_byte_offset.file == BRW_GENERAL_REGISTER_FILE);
   assert(!reg.abs && !reg.negate);
   assert(reg.type == dst.type);

   unsigned imm_byte_offset = reg.nr * REG_SIZE + reg.subnr;

   if (indirect_byte_offset.file == BRW_IMMEDIATE_VALUE) {
      imm_byte_offset += indirect_byte_offset.ud;

      reg.nr = imm_byte_offset / REG_SIZE;
      reg.subnr = imm_byte_offset % REG_SIZE;
      brw_MOV(p, dst, reg);
   } else {
      /* Prior to Broadwell, there are only 8 address registers. */
      assert(inst->exec_size <= 8 || devinfo->gen >= 8);

      /* We use VxH indirect addressing, clobbering a0.0 through a0.7. */
      struct brw_reg addr = vec8(brw_address_reg(0));

      /* The destination stride of an instruction (in bytes) must be greater
       * than or equal to the size of the rest of the instruction.  Since the
       * address register is of type UW, we can't use a D-type instruction.
       * In order to get around this, re retype to UW and use a stride.
       */
      indirect_byte_offset =
         retype(spread(indirect_byte_offset, 2), BRW_REGISTER_TYPE_UW);

      /* There are a number of reasons why we don't use the base offset here.
       * One reason is that the field is only 9 bits which means we can only
       * use it to access the first 16 GRFs.  Also, from the Haswell PRM
       * section "Register Region Restrictions":
       *
       *    "The lower bits of the AddressImmediate must not overflow to
       *    change the register address.  The lower 5 bits of Address
       *    Immediate when added to lower 5 bits of address register gives
       *    the sub-register offset. The upper bits of Address Immediate
       *    when added to upper bits of address register gives the register
       *    address. Any overflow from sub-register offset is dropped."
       *
       * Since the indirect may cause us to cross a register boundary, this
       * makes the base offset almost useless.  We could try and do something
       * clever where we use a actual base offset if base_offset % 32 == 0 but
       * that would mean we were generating different code depending on the
       * base offset.  Instead, for the sake of consistency, we'll just do the
       * add ourselves.  This restriction is only listed in the Haswell PRM
       * but empirical testing indicates that it applies on all older
       * generations and is lifted on Broadwell.
       *
       * In the end, while base_offset is nice to look at in the generated
       * code, using it saves us 0 instructions and would require quite a bit
       * of case-by-case work.  It's just not worth it.
       */
      brw_ADD(p, addr, indirect_byte_offset, brw_imm_uw(imm_byte_offset));

      if (type_sz(reg.type) > 4 &&
          ((devinfo->gen == 7 && !devinfo->is_haswell) ||
           devinfo->is_cherryview || gen_device_info_is_9lp(devinfo) ||
           !devinfo->has_64bit_types)) {
         /* IVB has an issue (which we found empirically) where it reads two
          * address register components per channel for indirectly addressed
          * 64-bit sources.
          *
          * From the Cherryview PRM Vol 7. "Register Region Restrictions":
          *
          *    "When source or destination datatype is 64b or operation is
          *    integer DWord multiply, indirect addressing must not be used."
          *
          * To work around both of these, we do two integer MOVs insead of one
          * 64-bit MOV.  Because no double value should ever cross a register
          * boundary, it's safe to use the immediate offset in the indirect
          * here to handle adding 4 bytes to the offset and avoid the extra
          * ADD to the register file.
          */
         brw_MOV(p, subscript(dst, BRW_REGISTER_TYPE_D, 0),
                    retype(brw_VxH_indirect(0, 0), BRW_REGISTER_TYPE_D));
         brw_MOV(p, subscript(dst, BRW_REGISTER_TYPE_D, 1),
                    retype(brw_VxH_indirect(0, 4), BRW_REGISTER_TYPE_D));
      } else {
         struct brw_reg ind_src = brw_VxH_indirect(0, 0);

         brw_inst *mov = brw_MOV(p, dst, retype(ind_src, reg.type));

         if (devinfo->gen == 6 && dst.file == BRW_MESSAGE_REGISTER_FILE &&
             !inst->get_next()->is_tail_sentinel() &&
             ((fs_inst *)inst->get_next())->mlen > 0) {
            /* From the Sandybridge PRM:
             *
             *    "[Errata: DevSNB(SNB)] If MRF register is updated by any
             *    instruction that “indexed/indirect” source AND is followed
             *    by a send, the instruction requires a “Switch”. This is to
             *    avoid race condition where send may dispatch before MRF is
             *    updated."
             */
            brw_inst_set_thread_control(devinfo, mov, BRW_THREAD_SWITCH);
         }
      }
   }
}

void
fs_generator::generate_shuffle(fs_inst *inst,
                               struct brw_reg dst,
                               struct brw_reg src,
                               struct brw_reg idx)
{
   /* Ivy bridge has some strange behavior that makes this a real pain to
    * implement for 64-bit values so we just don't bother.
    */
   assert(devinfo->gen >= 8 || devinfo->is_haswell || type_sz(src.type) <= 4);

   /* Because we're using the address register, we're limited to 8-wide
    * execution on gen7.  On gen8, we're limited to 16-wide by the address
    * register file and 8-wide for 64-bit types.  We could try and make this
    * instruction splittable higher up in the compiler but that gets weird
    * because it reads all of the channels regardless of execution size.  It's
    * easier just to split it here.
    */
   const unsigned lower_width =
      (devinfo->gen <= 7 || type_sz(src.type) > 4) ?
      8 : MIN2(16, inst->exec_size);

   brw_set_default_exec_size(p, cvt(lower_width) - 1);
   for (unsigned group = 0; group < inst->exec_size; group += lower_width) {
      brw_set_default_group(p, group);

      if ((src.vstride == 0 && src.hstride == 0) ||
          idx.file == BRW_IMMEDIATE_VALUE) {
         /* Trivial, the source is already uniform or the index is a constant.
          * We will typically not get here if the optimizer is doing its job,
          * but asserting would be mean.
          */
         const unsigned i = idx.file == BRW_IMMEDIATE_VALUE ? idx.ud : 0;
         brw_MOV(p, suboffset(dst, group), stride(suboffset(src, i), 0, 1, 0));
      } else {
         /* We use VxH indirect addressing, clobbering a0.0 through a0.7. */
         struct brw_reg addr = vec8(brw_address_reg(0));

         struct brw_reg group_idx = suboffset(idx, group);

         if (lower_width == 8 && group_idx.width == BRW_WIDTH_16) {
            /* Things get grumpy if the register is too wide. */
            group_idx.width--;
            group_idx.vstride--;
         }

         assert(type_sz(group_idx.type) <= 4);
         if (type_sz(group_idx.type) == 4) {
            /* The destination stride of an instruction (in bytes) must be
             * greater than or equal to the size of the rest of the
             * instruction.  Since the address register is of type UW, we
             * can't use a D-type instruction.  In order to get around this,
             * re retype to UW and use a stride.
             */
            group_idx = retype(spread(group_idx, 2), BRW_REGISTER_TYPE_W);
         }

         /* Take into account the component size and horizontal stride. */
         assert(src.vstride == src.hstride + src.width);
         brw_SHL(p, addr, group_idx,
                 brw_imm_uw(_mesa_logbase2(type_sz(src.type)) +
                            src.hstride - 1));

         /* Add on the register start offset */
         brw_ADD(p, addr, addr, brw_imm_uw(src.nr * REG_SIZE + src.subnr));

         if (type_sz(src.type) > 4 &&
             ((devinfo->gen == 7 && !devinfo->is_haswell) ||
              devinfo->is_cherryview || gen_device_info_is_9lp(devinfo))) {
            /* IVB has an issue (which we found empirically) where it reads
             * two address register components per channel for indirectly
             * addressed 64-bit sources.
             *
             * From the Cherryview PRM Vol 7. "Register Region Restrictions":
             *
             *    "When source or destination datatype is 64b or operation is
             *    integer DWord multiply, indirect addressing must not be
             *    used."
             *
             * To work around both of these, we do two integer MOVs insead of
             * one 64-bit MOV.  Because no double value should ever cross a
             * register boundary, it's safe to use the immediate offset in the
             * indirect here to handle adding 4 bytes to the offset and avoid
             * the extra ADD to the register file.
             */
            struct brw_reg gdst = suboffset(dst, group);
            struct brw_reg dst_d = retype(spread(gdst, 2),
                                          BRW_REGISTER_TYPE_D);
            brw_MOV(p, dst_d,
                    retype(brw_VxH_indirect(0, 0), BRW_REGISTER_TYPE_D));
            brw_MOV(p, byte_offset(dst_d, 4),
                    retype(brw_VxH_indirect(0, 4), BRW_REGISTER_TYPE_D));
         } else {
            brw_MOV(p, suboffset(dst, group),
                    retype(brw_VxH_indirect(0, 0), src.type));
         }
      }
   }
}

void
fs_generator::generate_quad_swizzle(const fs_inst *inst,
                                    struct brw_reg dst, struct brw_reg src,
                                    unsigned swiz)
{
   /* Requires a quad. */
   assert(inst->exec_size >= 4);

   if (src.file == BRW_IMMEDIATE_VALUE ||
       has_scalar_region(src)) {
      /* The value is uniform across all channels */
      brw_MOV(p, dst, src);

   } else if (devinfo->gen < 11 && type_sz(src.type) == 4) {
      /* This only works on 8-wide 32-bit values */
      assert(inst->exec_size == 8);
      assert(src.hstride == BRW_HORIZONTAL_STRIDE_1);
      assert(src.vstride == src.width + 1);
      brw_set_default_access_mode(p, BRW_ALIGN_16);
      struct brw_reg swiz_src = stride(src, 4, 4, 1);
      swiz_src.swizzle = swiz;
      brw_MOV(p, dst, swiz_src);

   } else {
      assert(src.hstride == BRW_HORIZONTAL_STRIDE_1);
      assert(src.vstride == src.width + 1);
      const struct brw_reg src_0 = suboffset(src, BRW_GET_SWZ(swiz, 0));

      switch (swiz) {
      case BRW_SWIZZLE_XXXX:
      case BRW_SWIZZLE_YYYY:
      case BRW_SWIZZLE_ZZZZ:
      case BRW_SWIZZLE_WWWW:
         brw_MOV(p, dst, stride(src_0, 4, 4, 0));
         break;

      case BRW_SWIZZLE_XXZZ:
      case BRW_SWIZZLE_YYWW:
         brw_MOV(p, dst, stride(src_0, 2, 2, 0));
         break;

      case BRW_SWIZZLE_XYXY:
      case BRW_SWIZZLE_ZWZW:
         assert(inst->exec_size == 4);
         brw_MOV(p, dst, stride(src_0, 0, 2, 1));
         break;

      default:
         assert(inst->force_writemask_all);
         brw_set_default_exec_size(p, cvt(inst->exec_size / 4) - 1);

         for (unsigned c = 0; c < 4; c++) {
            brw_inst *insn = brw_MOV(
               p, stride(suboffset(dst, c),
                         4 * inst->dst.stride, 1, 4 * inst->dst.stride),
               stride(suboffset(src, BRW_GET_SWZ(swiz, c)), 4, 1, 0));

            brw_inst_set_no_dd_clear(devinfo, insn, c < 3);
            brw_inst_set_no_dd_check(devinfo, insn, c > 0);
         }

         break;
      }
   }
}

void
fs_generator::generate_urb_read(fs_inst *inst,
                                struct brw_reg dst,
                                struct brw_reg header)
{
   assert(inst->size_written % REG_SIZE == 0);
   assert(header.file == BRW_GENERAL_REGISTER_FILE);
   assert(header.type == BRW_REGISTER_TYPE_UD);

   brw_inst *send = brw_next_insn(p, BRW_OPCODE_SEND);
   brw_set_dest(p, send, retype(dst, BRW_REGISTER_TYPE_UD));
   brw_set_src0(p, send, header);
   brw_set_src1(p, send, brw_imm_ud(0u));

   brw_inst_set_sfid(p->devinfo, send, BRW_SFID_URB);
   brw_inst_set_urb_opcode(p->devinfo, send, GEN8_URB_OPCODE_SIMD8_READ);

   if (inst->opcode == SHADER_OPCODE_URB_READ_SIMD8_PER_SLOT)
      brw_inst_set_urb_per_slot_offset(p->devinfo, send, true);

   brw_inst_set_mlen(p->devinfo, send, inst->mlen);
   brw_inst_set_rlen(p->devinfo, send, inst->size_written / REG_SIZE);
   brw_inst_set_header_present(p->devinfo, send, true);
   brw_inst_set_urb_global_offset(p->devinfo, send, inst->offset);
}

void
fs_generator::generate_urb_write(fs_inst *inst, struct brw_reg payload)
{
   brw_inst *insn;

    /* WaClearTDRRegBeforeEOTForNonPS.
     *
     *   WA: Clear tdr register before send EOT in all non-PS shader kernels
     *
     *   mov(8) tdr0:ud 0x0:ud {NoMask}"
     */
   if (inst->eot && p->devinfo->gen == 10) {
      brw_push_insn_state(p);
      brw_set_default_mask_control(p, BRW_MASK_DISABLE);
      brw_MOV(p, brw_tdr_reg(), brw_imm_uw(0));
      brw_pop_insn_state(p);
   }

   insn = brw_next_insn(p, BRW_OPCODE_SEND);

   brw_set_dest(p, insn, brw_null_reg());
   brw_set_src0(p, insn, payload);
   brw_set_src1(p, insn, brw_imm_ud(0u));

   brw_inst_set_sfid(p->devinfo, insn, BRW_SFID_URB);
   brw_inst_set_urb_opcode(p->devinfo, insn, GEN8_URB_OPCODE_SIMD8_WRITE);

   if (inst->opcode == SHADER_OPCODE_URB_WRITE_SIMD8_PER_SLOT ||
       inst->opcode == SHADER_OPCODE_URB_WRITE_SIMD8_MASKED_PER_SLOT)
      brw_inst_set_urb_per_slot_offset(p->devinfo, insn, true);

   if (inst->opcode == SHADER_OPCODE_URB_WRITE_SIMD8_MASKED ||
       inst->opcode == SHADER_OPCODE_URB_WRITE_SIMD8_MASKED_PER_SLOT)
      brw_inst_set_urb_channel_mask_present(p->devinfo, insn, true);

   brw_inst_set_mlen(p->devinfo, insn, inst->mlen);
   brw_inst_set_rlen(p->devinfo, insn, 0);
   brw_inst_set_eot(p->devinfo, insn, inst->eot);
   brw_inst_set_header_present(p->devinfo, insn, true);
   brw_inst_set_urb_global_offset(p->devinfo, insn, inst->offset);
}

void
fs_generator::generate_cs_terminate(fs_inst *inst, struct brw_reg payload)
{
   struct brw_inst *insn;

   insn = brw_next_insn(p, BRW_OPCODE_SEND);

   brw_set_dest(p, insn, retype(brw_null_reg(), BRW_REGISTER_TYPE_UW));
   brw_set_src0(p, insn, retype(payload, BRW_REGISTER_TYPE_UW));
   brw_set_src1(p, insn, brw_imm_ud(0u));

   /* Terminate a compute shader by sending a message to the thread spawner.
    */
   brw_inst_set_sfid(devinfo, insn, BRW_SFID_THREAD_SPAWNER);
   brw_inst_set_mlen(devinfo, insn, 1);
   brw_inst_set_rlen(devinfo, insn, 0);
   brw_inst_set_eot(devinfo, insn, inst->eot);
   brw_inst_set_header_present(devinfo, insn, false);

   brw_inst_set_ts_opcode(devinfo, insn, 0); /* Dereference resource */
   brw_inst_set_ts_request_type(devinfo, insn, 0); /* Root thread */

   /* Note that even though the thread has a URB resource associated with it,
    * we set the "do not dereference URB" bit, because the URB resource is
    * managed by the fixed-function unit, so it will free it automatically.
    */
   brw_inst_set_ts_resource_select(devinfo, insn, 1); /* Do not dereference URB */

   brw_inst_set_mask_control(devinfo, insn, BRW_MASK_DISABLE);
}

void
fs_generator::generate_barrier(fs_inst *, struct brw_reg src)
{
   brw_barrier(p, src);
   brw_WAIT(p);
}

bool
fs_generator::generate_linterp(fs_inst *inst,
                               struct brw_reg dst, struct brw_reg *src)
{
   /* PLN reads:
    *                      /   in SIMD16   \
    *    -----------------------------------
    *   | src1+0 | src1+1 | src1+2 | src1+3 |
    *   |-----------------------------------|
    *   |(x0, x1)|(y0, y1)|(x2, x3)|(y2, y3)|
    *    -----------------------------------
    *
    * but for the LINE/MAC pair, the LINE reads Xs and the MAC reads Ys:
    *
    *    -----------------------------------
    *   | src1+0 | src1+1 | src1+2 | src1+3 |
    *   |-----------------------------------|
    *   |(x0, x1)|(y0, y1)|        |        | in SIMD8
    *   |-----------------------------------|
    *   |(x0, x1)|(x2, x3)|(y0, y1)|(y2, y3)| in SIMD16
    *    -----------------------------------
    *
    * See also: emit_interpolation_setup_gen4().
    */
   struct brw_reg delta_x = src[0];
   struct brw_reg delta_y = offset(src[0], inst->exec_size / 8);
   struct brw_reg interp = stride(src[1], 0, 1, 0);
   brw_inst *i[2];

   /* fs_visitor::lower_linterp() will do the lowering to MAD instructions for
    * us on gen11+
    */
   assert(devinfo->gen < 11);

   if (devinfo->has_pln) {
      if (devinfo->gen <= 6 && (delta_x.nr & 1) != 0) {
         /* From the Sandy Bridge PRM Vol. 4, Pt. 2, Section 8.3.53, "Plane":
          *
          *    "[DevSNB]:<src1> must be even register aligned.
          *
          * This restriction is lifted on Ivy Bridge.
          *
          * This means that we need to split PLN into LINE+MAC on-the-fly.
          * Unfortunately, the inputs are laid out for PLN and not LINE+MAC so
          * we have to split into SIMD8 pieces.  For gen4 (!has_pln), the
          * coordinate registers are laid out differently so we leave it as a
          * SIMD16 instruction.
          */
         assert(inst->exec_size == 8 || inst->exec_size == 16);
         assert(inst->group % 16 == 0);

         brw_push_insn_state(p);
         brw_set_default_exec_size(p, BRW_EXECUTE_8);

         /* Thanks to two accumulators, we can emit all the LINEs and then all
          * the MACs.  This improves parallelism a bit.
          */
         for (unsigned g = 0; g < inst->exec_size / 8; g++) {
            brw_inst *line = brw_LINE(p, brw_null_reg(), interp,
                                      offset(delta_x, g * 2));
            brw_inst_set_group(devinfo, line, inst->group + g * 8);

            /* LINE writes the accumulator automatically on gen4-5.  On Sandy
             * Bridge and later, we have to explicitly enable it.
             */
            if (devinfo->gen >= 6)
               brw_inst_set_acc_wr_control(p->devinfo, line, true);

            /* brw_set_default_saturate() is called before emitting
             * instructions, so the saturate bit is set in each instruction,
             * so we need to unset it on the LINE instructions.
             */
            brw_inst_set_saturate(p->devinfo, line, false);
         }

         for (unsigned g = 0; g < inst->exec_size / 8; g++) {
            brw_inst *mac = brw_MAC(p, offset(dst, g), suboffset(interp, 1),
                                    offset(delta_x, g * 2 + 1));
            brw_inst_set_group(devinfo, mac, inst->group + g * 8);
            brw_inst_set_cond_modifier(p->devinfo, mac, inst->conditional_mod);
         }

         brw_pop_insn_state(p);

         return true;
      } else {
         brw_PLN(p, dst, interp, delta_x);

         return false;
      }
   } else {
      i[0] = brw_LINE(p, brw_null_reg(), interp, delta_x);
      i[1] = brw_MAC(p, dst, suboffset(interp, 1), delta_y);

      brw_inst_set_cond_modifier(p->devinfo, i[1], inst->conditional_mod);

      /* brw_set_default_saturate() is called before emitting instructions, so
       * the saturate bit is set in each instruction, so we need to unset it on
       * the first instruction.
       */
      brw_inst_set_saturate(p->devinfo, i[0], false);

      return true;
   }
}

void
fs_generator::generate_get_buffer_size(fs_inst *inst,
                                       struct brw_reg dst,
                                       struct brw_reg src,
                                       struct brw_reg surf_index)
{
   assert(devinfo->gen >= 7);
   assert(surf_index.file == BRW_IMMEDIATE_VALUE);

   uint32_t simd_mode;
   int rlen = 4;

   switch (inst->exec_size) {
   case 8:
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD8;
      break;
   case 16:
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
      break;
   default:
      unreachable("Invalid width for texture instruction");
   }

   if (simd_mode == BRW_SAMPLER_SIMD_MODE_SIMD16) {
      rlen = 8;
      dst = vec16(dst);
   }

   brw_SAMPLE(p,
              retype(dst, BRW_REGISTER_TYPE_UW),
              inst->base_mrf,
              src,
              surf_index.ud,
              0,
              GEN5_SAMPLER_MESSAGE_SAMPLE_RESINFO,
              rlen, /* response length */
              inst->mlen,
              inst->header_size > 0,
              simd_mode,
              BRW_SAMPLER_RETURN_FORMAT_SINT32);
}

void
fs_generator::generate_tex(fs_inst *inst, struct brw_reg dst,
                           struct brw_reg surface_index,
                           struct brw_reg sampler_index)
{
   assert(devinfo->gen < 7);
   assert(inst->size_written % REG_SIZE == 0);
   int msg_type = -1;
   uint32_t simd_mode;
   uint32_t return_format;

   /* Sampler EOT message of less than the dispatch width would kill the
    * thread prematurely.
    */
   assert(!inst->eot || inst->exec_size == dispatch_width);

   switch (dst.type) {
   case BRW_REGISTER_TYPE_D:
      return_format = BRW_SAMPLER_RETURN_FORMAT_SINT32;
      break;
   case BRW_REGISTER_TYPE_UD:
      return_format = BRW_SAMPLER_RETURN_FORMAT_UINT32;
      break;
   default:
      return_format = BRW_SAMPLER_RETURN_FORMAT_FLOAT32;
      break;
   }

   /* Stomp the resinfo output type to UINT32.  On gens 4-5, the output type
    * is set as part of the message descriptor.  On gen4, the PRM seems to
    * allow UINT32 and FLOAT32 (i965 PRM, Vol. 4 Section 4.8.1.1), but on
    * later gens UINT32 is required.  Once you hit Sandy Bridge, the bit is
    * gone from the message descriptor entirely and you just get UINT32 all
    * the time regasrdless.  Since we can really only do non-UINT32 on gen4,
    * just stomp it to UINT32 all the time.
    */
   if (inst->opcode == SHADER_OPCODE_TXS)
      return_format = BRW_SAMPLER_RETURN_FORMAT_UINT32;

   switch (inst->exec_size) {
   case 8:
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD8;
      break;
   case 16:
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
      break;
   default:
      unreachable("Invalid width for texture instruction");
   }

   if (devinfo->gen >= 5) {
      switch (inst->opcode) {
      case SHADER_OPCODE_TEX:
         if (inst->shadow_compare) {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_COMPARE;
         } else {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE;
         }
         break;
      case FS_OPCODE_TXB:
         if (inst->shadow_compare) {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_BIAS_COMPARE;
         } else {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_BIAS;
         }
         break;
      case SHADER_OPCODE_TXL:
         if (inst->shadow_compare) {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LOD_COMPARE;
         } else {
            msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LOD;
         }
         break;
      case SHADER_OPCODE_TXS:
         msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_RESINFO;
         break;
      case SHADER_OPCODE_TXD:
         assert(!inst->shadow_compare);
         msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_DERIVS;
         break;
      case SHADER_OPCODE_TXF:
         msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LD;
         break;
      case SHADER_OPCODE_TXF_CMS:
         msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LD;
         break;
      case SHADER_OPCODE_LOD:
         msg_type = GEN5_SAMPLER_MESSAGE_LOD;
         break;
      case SHADER_OPCODE_TG4:
         assert(devinfo->gen == 6);
         assert(!inst->shadow_compare);
         msg_type = GEN7_SAMPLER_MESSAGE_SAMPLE_GATHER4;
         break;
      case SHADER_OPCODE_SAMPLEINFO:
         msg_type = GEN6_SAMPLER_MESSAGE_SAMPLE_SAMPLEINFO;
         break;
      default:
         unreachable("not reached");
      }
   } else {
      switch (inst->opcode) {
      case SHADER_OPCODE_TEX:
         /* Note that G45 and older determines shadow compare and dispatch width
          * from message length for most messages.
          */
         if (inst->exec_size == 8) {
            msg_type = BRW_SAMPLER_MESSAGE_SIMD8_SAMPLE;
            if (inst->shadow_compare) {
               assert(inst->mlen == 6);
            } else {
               assert(inst->mlen <= 4);
            }
         } else {
            if (inst->shadow_compare) {
               msg_type = BRW_SAMPLER_MESSAGE_SIMD16_SAMPLE_COMPARE;
               assert(inst->mlen == 9);
            } else {
               msg_type = BRW_SAMPLER_MESSAGE_SIMD16_SAMPLE;
               assert(inst->mlen <= 7 && inst->mlen % 2 == 1);
            }
         }
         break;
      case FS_OPCODE_TXB:
         if (inst->shadow_compare) {
            assert(inst->exec_size == 8);
            assert(inst->mlen == 6);
            msg_type = BRW_SAMPLER_MESSAGE_SIMD8_SAMPLE_BIAS_COMPARE;
         } else {
            assert(inst->mlen == 9);
            msg_type = BRW_SAMPLER_MESSAGE_SIMD16_SAMPLE_BIAS;
            simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
         }
         break;
      case SHADER_OPCODE_TXL:
         if (inst->shadow_compare) {
            assert(inst->exec_size == 8);
            assert(inst->mlen == 6);
            msg_type = BRW_SAMPLER_MESSAGE_SIMD8_SAMPLE_LOD_COMPARE;
         } else {
            assert(inst->mlen == 9);
            msg_type = BRW_SAMPLER_MESSAGE_SIMD16_SAMPLE_LOD;
            simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
         }
         break;
      case SHADER_OPCODE_TXD:
         /* There is no sample_d_c message; comparisons are done manually */
         assert(inst->exec_size == 8);
         assert(inst->mlen == 7 || inst->mlen == 10);
         msg_type = BRW_SAMPLER_MESSAGE_SIMD8_SAMPLE_GRADIENTS;
         break;
      case SHADER_OPCODE_TXF:
         assert(inst->mlen <= 9 && inst->mlen % 2 == 1);
         msg_type = BRW_SAMPLER_MESSAGE_SIMD16_LD;
         simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
         break;
      case SHADER_OPCODE_TXS:
         assert(inst->mlen == 3);
         msg_type = BRW_SAMPLER_MESSAGE_SIMD16_RESINFO;
         simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
         break;
      default:
         unreachable("not reached");
      }
   }
   assert(msg_type != -1);

   if (simd_mode == BRW_SAMPLER_SIMD_MODE_SIMD16) {
      dst = vec16(dst);
   }

   assert(sampler_index.type == BRW_REGISTER_TYPE_UD);

   /* Load the message header if present.  If there's a texture offset,
    * we need to set it up explicitly and load the offset bitfield.
    * Otherwise, we can use an implied move from g0 to the first message reg.
    */
   struct brw_reg src = brw_null_reg();
   if (inst->header_size != 0) {
      if (devinfo->gen < 6 && !inst->offset) {
         /* Set up an implied move from g0 to the MRF. */
         src = retype(brw_vec8_grf(0, 0), BRW_REGISTER_TYPE_UW);
      } else {
         assert(inst->base_mrf != -1);
         struct brw_reg header_reg = brw_message_reg(inst->base_mrf);

         brw_push_insn_state(p);
         brw_set_default_exec_size(p, BRW_EXECUTE_8);
         brw_set_default_mask_control(p, BRW_MASK_DISABLE);
         brw_set_default_compression_control(p, BRW_COMPRESSION_NONE);
         /* Explicitly set up the message header by copying g0 to the MRF. */
         brw_MOV(p, header_reg, brw_vec8_grf(0, 0));

         brw_set_default_exec_size(p, BRW_EXECUTE_1);
         if (inst->offset) {
            /* Set the offset bits in DWord 2. */
            brw_MOV(p, get_element_ud(header_reg, 2),
                       brw_imm_ud(inst->offset));
         }

         brw_pop_insn_state(p);
      }
   }

   uint32_t base_binding_table_index;
   switch (inst->opcode) {
   case SHADER_OPCODE_TG4:
      base_binding_table_index = prog_data->binding_table.gather_texture_start;
      break;
   default:
      base_binding_table_index = prog_data->binding_table.texture_start;
      break;
   }

   assert(surface_index.file == BRW_IMMEDIATE_VALUE);
   assert(sampler_index.file == BRW_IMMEDIATE_VALUE);

   brw_SAMPLE(p,
              retype(dst, BRW_REGISTER_TYPE_UW),
              inst->base_mrf,
              src,
              surface_index.ud + base_binding_table_index,
              sampler_index.ud % 16,
              msg_type,
              inst->size_written / REG_SIZE,
              inst->mlen,
              inst->header_size != 0,
              simd_mode,
              return_format);
}


/* For OPCODE_DDX and OPCODE_DDY, per channel of output we've got input
 * looking like:
 *
 * arg0: ss0.tl ss0.tr ss0.bl ss0.br ss1.tl ss1.tr ss1.bl ss1.br
 *
 * Ideally, we want to produce:
 *
 *           DDX                     DDY
 * dst: (ss0.tr - ss0.tl)     (ss0.tl - ss0.bl)
 *      (ss0.tr - ss0.tl)     (ss0.tr - ss0.br)
 *      (ss0.br - ss0.bl)     (ss0.tl - ss0.bl)
 *      (ss0.br - ss0.bl)     (ss0.tr - ss0.br)
 *      (ss1.tr - ss1.tl)     (ss1.tl - ss1.bl)
 *      (ss1.tr - ss1.tl)     (ss1.tr - ss1.br)
 *      (ss1.br - ss1.bl)     (ss1.tl - ss1.bl)
 *      (ss1.br - ss1.bl)     (ss1.tr - ss1.br)
 *
 * and add another set of two more subspans if in 16-pixel dispatch mode.
 *
 * For DDX, it ends up being easy: width = 2, horiz=0 gets us the same result
 * for each pair, and vertstride = 2 jumps us 2 elements after processing a
 * pair.  But the ideal approximation may impose a huge performance cost on
 * sample_d.  On at least Haswell, sample_d instruction does some
 * optimizations if the same LOD is used for all pixels in the subspan.
 *
 * For DDY, we need to use ALIGN16 mode since it's capable of doing the
 * appropriate swizzling.
 */
void
fs_generator::generate_ddx(const fs_inst *inst,
                           struct brw_reg dst, struct brw_reg src)
{
   unsigned vstride, width;

   if (inst->opcode == FS_OPCODE_DDX_FINE) {
      /* produce accurate derivatives */
      vstride = BRW_VERTICAL_STRIDE_2;
      width = BRW_WIDTH_2;
   } else {
      /* replicate the derivative at the top-left pixel to other pixels */
      vstride = BRW_VERTICAL_STRIDE_4;
      width = BRW_WIDTH_4;
   }

   struct brw_reg src0 = byte_offset(src, type_sz(src.type));;
   struct brw_reg src1 = src;

   src0.vstride = vstride;
   src0.width   = width;
   src0.hstride = BRW_HORIZONTAL_STRIDE_0;
   src1.vstride = vstride;
   src1.width   = width;
   src1.hstride = BRW_HORIZONTAL_STRIDE_0;

   brw_ADD(p, dst, src0, negate(src1));
}

/* The negate_value boolean is used to negate the derivative computation for
 * FBOs, since they place the origin at the upper left instead of the lower
 * left.
 */
void
fs_generator::generate_ddy(const fs_inst *inst,
                           struct brw_reg dst, struct brw_reg src)
{
   const uint32_t type_size = type_sz(src.type);

   if (inst->opcode == FS_OPCODE_DDY_FINE) {
      /* produce accurate derivatives.
       *
       * From the Broadwell PRM, Volume 7 (3D-Media-GPGPU)
       * "Register Region Restrictions", Section "1. Special Restrictions":
       *
       *    "In Align16 mode, the channel selects and channel enables apply to
       *     a pair of half-floats, because these parameters are defined for
       *     DWord elements ONLY. This is applicable when both source and
       *     destination are half-floats."
       *
       * So for half-float operations we use the Gen11+ Align1 path. CHV
       * inherits its FP16 hardware from SKL, so it is not affected.
       */
      if (devinfo->gen >= 11 ||
          (devinfo->is_broadwell && src.type == BRW_REGISTER_TYPE_HF)) {
         src = stride(src, 0, 2, 1);
         struct brw_reg src_0  = byte_offset(src,  0 * type_size);
         struct brw_reg src_2  = byte_offset(src,  2 * type_size);
         struct brw_reg src_4  = byte_offset(src,  4 * type_size);
         struct brw_reg src_6  = byte_offset(src,  6 * type_size);
         struct brw_reg src_8  = byte_offset(src,  8 * type_size);
         struct brw_reg src_10 = byte_offset(src, 10 * type_size);
         struct brw_reg src_12 = byte_offset(src, 12 * type_size);
         struct brw_reg src_14 = byte_offset(src, 14 * type_size);

         struct brw_reg dst_0  = byte_offset(dst,  0 * type_size);
         struct brw_reg dst_4  = byte_offset(dst,  4 * type_size);
         struct brw_reg dst_8  = byte_offset(dst,  8 * type_size);
         struct brw_reg dst_12 = byte_offset(dst, 12 * type_size);

         brw_push_insn_state(p);
         brw_set_default_exec_size(p, BRW_EXECUTE_4);

         brw_ADD(p, dst_0, negate(src_0), src_2);
         brw_ADD(p, dst_4, negate(src_4), src_6);

         if (inst->exec_size == 16) {
            brw_ADD(p, dst_8,  negate(src_8),  src_10);
            brw_ADD(p, dst_12, negate(src_12), src_14);
         }

         brw_pop_insn_state(p);
      } else {
         struct brw_reg src0 = stride(src, 4, 4, 1);
         struct brw_reg src1 = stride(src, 4, 4, 1);
         src0.swizzle = BRW_SWIZZLE_XYXY;
         src1.swizzle = BRW_SWIZZLE_ZWZW;

         brw_push_insn_state(p);
         brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_ADD(p, dst, negate(src0), src1);
         brw_pop_insn_state(p);
      }
   } else {
      /* replicate the derivative at the top-left pixel to other pixels */
      struct brw_reg src0 = byte_offset(stride(src, 4, 4, 0), 0 * type_size);
      struct brw_reg src1 = byte_offset(stride(src, 4, 4, 0), 2 * type_size);

      brw_ADD(p, dst, negate(src0), src1);
   }
}

void
fs_generator::generate_discard_jump(fs_inst *)
{
   assert(devinfo->gen >= 6);

   /* This HALT will be patched up at FB write time to point UIP at the end of
    * the program, and at brw_uip_jip() JIP will be set to the end of the
    * current block (or the program).
    */
   this->discard_halt_patches.push_tail(new(mem_ctx) ip_record(p->nr_insn));
   gen6_HALT(p);
}

void
fs_generator::generate_scratch_write(fs_inst *inst, struct brw_reg src)
{
   /* The 32-wide messages only respect the first 16-wide half of the channel
    * enable signals which are replicated identically for the second group of
    * 16 channels, so we cannot use them unless the write is marked
    * force_writemask_all.
    */
   const unsigned lower_size = inst->force_writemask_all ? inst->exec_size :
                               MIN2(16, inst->exec_size);
   const unsigned block_size = 4 * lower_size / REG_SIZE;
   assert(inst->mlen != 0);

   brw_push_insn_state(p);
   brw_set_default_exec_size(p, cvt(lower_size) - 1);
   brw_set_default_compression(p, lower_size > 8);

   for (unsigned i = 0; i < inst->exec_size / lower_size; i++) {
      brw_set_default_group(p, inst->group + lower_size * i);

      brw_MOV(p, brw_uvec_mrf(lower_size, inst->base_mrf + 1, 0),
              retype(offset(src, block_size * i), BRW_REGISTER_TYPE_UD));

      brw_oword_block_write_scratch(p, brw_message_reg(inst->base_mrf),
                                    block_size,
                                    inst->offset + block_size * REG_SIZE * i);
   }

   brw_pop_insn_state(p);
}

void
fs_generator::generate_scratch_read(fs_inst *inst, struct brw_reg dst)
{
   assert(inst->exec_size <= 16 || inst->force_writemask_all);
   assert(inst->mlen != 0);

   brw_oword_block_read_scratch(p, dst, brw_message_reg(inst->base_mrf),
                                inst->exec_size / 8, inst->offset);
}

void
fs_generator::generate_scratch_read_gen7(fs_inst *inst, struct brw_reg dst)
{
   assert(inst->exec_size <= 16 || inst->force_writemask_all);

   gen7_block_read_scratch(p, dst, inst->exec_size / 8, inst->offset);
}

void
fs_generator::generate_uniform_pull_constant_load(fs_inst *inst,
                                                  struct brw_reg dst,
                                                  struct brw_reg index,
                                                  struct brw_reg offset)
{
   assert(type_sz(dst.type) == 4);
   assert(inst->mlen != 0);

   assert(index.file == BRW_IMMEDIATE_VALUE &&
          index.type == BRW_REGISTER_TYPE_UD);
   uint32_t surf_index = index.ud;

   assert(offset.file == BRW_IMMEDIATE_VALUE &&
          offset.type == BRW_REGISTER_TYPE_UD);
   uint32_t read_offset = offset.ud;

   brw_oword_block_read(p, dst, brw_message_reg(inst->base_mrf),
                        read_offset, surf_index);
}

void
fs_generator::generate_uniform_pull_constant_load_gen7(fs_inst *inst,
                                                       struct brw_reg dst,
                                                       struct brw_reg index,
                                                       struct brw_reg payload)
{
   assert(index.type == BRW_REGISTER_TYPE_UD);
   assert(payload.file == BRW_GENERAL_REGISTER_FILE);
   assert(type_sz(dst.type) == 4);

   if (index.file == BRW_IMMEDIATE_VALUE) {
      const uint32_t surf_index = index.ud;

      brw_push_insn_state(p);
      brw_set_default_mask_control(p, BRW_MASK_DISABLE);
      brw_inst *send = brw_next_insn(p, BRW_OPCODE_SEND);
      brw_pop_insn_state(p);

      brw_inst_set_sfid(devinfo, send, GEN6_SFID_DATAPORT_CONSTANT_CACHE);
      brw_set_dest(p, send, retype(dst, BRW_REGISTER_TYPE_UD));
      brw_set_src0(p, send, retype(payload, BRW_REGISTER_TYPE_UD));
      brw_set_desc(p, send,
                   brw_message_desc(devinfo, 1, DIV_ROUND_UP(inst->size_written,
                                                             REG_SIZE), true) |
                   brw_dp_read_desc(devinfo, surf_index,
                                    BRW_DATAPORT_OWORD_BLOCK_DWORDS(inst->exec_size),
                                    GEN7_DATAPORT_DC_OWORD_BLOCK_READ,
                                    BRW_DATAPORT_READ_TARGET_DATA_CACHE));

   } else {
      struct brw_reg addr = vec1(retype(brw_address_reg(0), BRW_REGISTER_TYPE_UD));

      brw_push_insn_state(p);
      brw_set_default_mask_control(p, BRW_MASK_DISABLE);

      /* a0.0 = surf_index & 0xff */
      brw_inst *insn_and = brw_next_insn(p, BRW_OPCODE_AND);
      brw_inst_set_exec_size(p->devinfo, insn_and, BRW_EXECUTE_1);
      brw_set_dest(p, insn_and, addr);
      brw_set_src0(p, insn_and, vec1(retype(index, BRW_REGISTER_TYPE_UD)));
      brw_set_src1(p, insn_and, brw_imm_ud(0x0ff));

      /* dst = send(payload, a0.0 | <descriptor>) */
      brw_send_indirect_message(
         p, GEN6_SFID_DATAPORT_CONSTANT_CACHE,
         retype(dst, BRW_REGISTER_TYPE_UD),
         retype(payload, BRW_REGISTER_TYPE_UD), addr,
         brw_message_desc(devinfo, 1,
                          DIV_ROUND_UP(inst->size_written, REG_SIZE), true) |
         brw_dp_read_desc(devinfo, 0 /* surface */,
                          BRW_DATAPORT_OWORD_BLOCK_DWORDS(inst->exec_size),
                          GEN7_DATAPORT_DC_OWORD_BLOCK_READ,
                          BRW_DATAPORT_READ_TARGET_DATA_CACHE),
         false /* EOT */);

      brw_pop_insn_state(p);
   }
}

void
fs_generator::generate_varying_pull_constant_load_gen4(fs_inst *inst,
                                                       struct brw_reg dst,
                                                       struct brw_reg index)
{
   assert(devinfo->gen < 7); /* Should use the gen7 variant. */
   assert(inst->header_size != 0);
   assert(inst->mlen);

   assert(index.file == BRW_IMMEDIATE_VALUE &&
          index.type == BRW_REGISTER_TYPE_UD);
   uint32_t surf_index = index.ud;

   uint32_t simd_mode, rlen, msg_type;
   if (inst->exec_size == 16) {
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
      rlen = 8;
   } else {
      assert(inst->exec_size == 8);
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD8;
      rlen = 4;
   }

   if (devinfo->gen >= 5)
      msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LD;
   else {
      /* We always use the SIMD16 message so that we only have to load U, and
       * not V or R.
       */
      msg_type = BRW_SAMPLER_MESSAGE_SIMD16_LD;
      assert(inst->mlen == 3);
      assert(inst->size_written == 8 * REG_SIZE);
      rlen = 8;
      simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
   }

   struct brw_reg header = brw_vec8_grf(0, 0);
   gen6_resolve_implied_move(p, &header, inst->base_mrf);

   brw_inst *send = brw_next_insn(p, BRW_OPCODE_SEND);
   brw_inst_set_compression(devinfo, send, false);
   brw_inst_set_sfid(devinfo, send, BRW_SFID_SAMPLER);
   brw_set_dest(p, send, retype(dst, BRW_REGISTER_TYPE_UW));
   brw_set_src0(p, send, header);
   if (devinfo->gen < 6)
      brw_inst_set_base_mrf(p->devinfo, send, inst->base_mrf);

   /* Our surface is set up as floats, regardless of what actual data is
    * stored in it.
    */
   uint32_t return_format = BRW_SAMPLER_RETURN_FORMAT_FLOAT32;
   brw_set_desc(p, send,
                brw_message_desc(devinfo, inst->mlen, rlen, inst->header_size) |
                brw_sampler_desc(devinfo, surf_index,
                                 0, /* sampler (unused) */
                                 msg_type, simd_mode, return_format));
}

void
fs_generator::generate_pixel_interpolator_query(fs_inst *inst,
                                                struct brw_reg dst,
                                                struct brw_reg src,
                                                struct brw_reg msg_data,
                                                unsigned msg_type)
{
   const bool has_payload = inst->src[0].file != BAD_FILE;
   assert(msg_data.type == BRW_REGISTER_TYPE_UD);
   assert(inst->size_written % REG_SIZE == 0);

   brw_pixel_interpolator_query(p,
         retype(dst, BRW_REGISTER_TYPE_UW),
         /* If we don't have a payload, what we send doesn't matter */
         has_payload ? src : brw_vec8_grf(0, 0),
         inst->pi_noperspective,
         msg_type,
         msg_data,
         has_payload ? 2 * inst->exec_size / 8 : 1,
         inst->size_written / REG_SIZE);
}

/* Sets vstride=1, width=4, hstride=0 of register src1 during
 * the ADD instruction.
 */
void
fs_generator::generate_set_sample_id(fs_inst *inst,
                                     struct brw_reg dst,
                                     struct brw_reg src0,
                                     struct brw_reg src1)
{
   assert(dst.type == BRW_REGISTER_TYPE_D ||
          dst.type == BRW_REGISTER_TYPE_UD);
   assert(src0.type == BRW_REGISTER_TYPE_D ||
          src0.type == BRW_REGISTER_TYPE_UD);

   const struct brw_reg reg = stride(src1, 1, 4, 0);
   const unsigned lower_size = MIN2(inst->exec_size,
                                    devinfo->gen >= 8 ? 16 : 8);

   for (unsigned i = 0; i < inst->exec_size / lower_size; i++) {
      brw_inst *insn = brw_ADD(p, offset(dst, i * lower_size / 8),
                               offset(src0, (src0.vstride == 0 ? 0 : (1 << (src0.vstride - 1)) *
                                             (i * lower_size / (1 << src0.width))) *
                                            type_sz(src0.type) / REG_SIZE),
                               suboffset(reg, i * lower_size / 4));
      brw_inst_set_exec_size(devinfo, insn, cvt(lower_size) - 1);
      brw_inst_set_group(devinfo, insn, inst->group + lower_size * i);
      brw_inst_set_compression(devinfo, insn, lower_size > 8);
   }
}

void
fs_generator::generate_pack_half_2x16_split(fs_inst *,
                                            struct brw_reg dst,
                                            struct brw_reg x,
                                            struct brw_reg y)
{
   assert(devinfo->gen >= 7);
   assert(dst.type == BRW_REGISTER_TYPE_UD);
   assert(x.type == BRW_REGISTER_TYPE_F);
   assert(y.type == BRW_REGISTER_TYPE_F);

   /* From the Ivybridge PRM, Vol4, Part3, Section 6.27 f32to16:
    *
    *   Because this instruction does not have a 16-bit floating-point type,
    *   the destination data type must be Word (W).
    *
    *   The destination must be DWord-aligned and specify a horizontal stride
    *   (HorzStride) of 2. The 16-bit result is stored in the lower word of
    *   each destination channel and the upper word is not modified.
    */
   struct brw_reg dst_w = spread(retype(dst, BRW_REGISTER_TYPE_W), 2);

   /* Give each 32-bit channel of dst the form below, where "." means
    * unchanged.
    *   0x....hhhh
    */
   brw_F32TO16(p, dst_w, y);

   /* Now the form:
    *   0xhhhh0000
    */
   brw_SHL(p, dst, dst, brw_imm_ud(16u));

   /* And, finally the form of packHalf2x16's output:
    *   0xhhhhllll
    */
   brw_F32TO16(p, dst_w, x);
}

void
fs_generator::generate_shader_time_add(fs_inst *,
                                       struct brw_reg payload,
                                       struct brw_reg offset,
                                       struct brw_reg value)
{
   assert(devinfo->gen >= 7);
   brw_push_insn_state(p);
   brw_set_default_mask_control(p, true);

   assert(payload.file == BRW_GENERAL_REGISTER_FILE);
   struct brw_reg payload_offset = retype(brw_vec1_grf(payload.nr, 0),
                                          offset.type);
   struct brw_reg payload_value = retype(brw_vec1_grf(payload.nr + 1, 0),
                                         value.type);

   assert(offset.file == BRW_IMMEDIATE_VALUE);
   if (value.file == BRW_GENERAL_REGISTER_FILE) {
      value.width = BRW_WIDTH_1;
      value.hstride = BRW_HORIZONTAL_STRIDE_0;
      value.vstride = BRW_VERTICAL_STRIDE_0;
   } else {
      assert(value.file == BRW_IMMEDIATE_VALUE);
   }

   /* Trying to deal with setup of the params from the IR is crazy in the FS8
    * case, and we don't really care about squeezing every bit of performance
    * out of this path, so we just emit the MOVs from here.
    */
   brw_MOV(p, payload_offset, offset);
   brw_MOV(p, payload_value, value);
   brw_shader_time_add(p, payload,
                       prog_data->binding_table.shader_time_start);
   brw_pop_insn_state(p);
}

void
fs_generator::enable_debug(const char *shader_name)
{
   debug_flag = true;
   this->shader_name = shader_name;
}

int
fs_generator::generate_code(const cfg_t *cfg, int dispatch_width)
{
   /* align to 64 byte boundary. */
   while (p->next_insn_offset % 64)
      brw_NOP(p);

   this->dispatch_width = dispatch_width;

   int start_offset = p->next_insn_offset;
   int spill_count = 0, fill_count = 0;
   int loop_count = 0;

   struct disasm_info *disasm_info = disasm_initialize(devinfo, cfg);

   foreach_block_and_inst (block, fs_inst, inst, cfg) {
      if (inst->opcode == SHADER_OPCODE_UNDEF)
         continue;

      struct brw_reg src[4], dst;
      unsigned int last_insn_offset = p->next_insn_offset;
      bool multiple_instructions_emitted = false;

      /* From the Broadwell PRM, Volume 7, "3D-Media-GPGPU", in the
       * "Register Region Restrictions" section: for BDW, SKL:
       *
       *    "A POW/FDIV operation must not be followed by an instruction
       *     that requires two destination registers."
       *
       * The documentation is often lacking annotations for Atom parts,
       * and empirically this affects CHV as well.
       */
      if (devinfo->gen >= 8 &&
          devinfo->gen <= 9 &&
          p->nr_insn > 1 &&
          brw_inst_opcode(devinfo, brw_last_inst) == BRW_OPCODE_MATH &&
          brw_inst_math_function(devinfo, brw_last_inst) == BRW_MATH_FUNCTION_POW &&
          inst->dst.component_size(inst->exec_size) > REG_SIZE) {
         brw_NOP(p);
         last_insn_offset = p->next_insn_offset;
      }

      if (unlikely(debug_flag))
         disasm_annotate(disasm_info, inst, p->next_insn_offset);

      /* If the instruction writes to more than one register, it needs to be
       * explicitly marked as compressed on Gen <= 5.  On Gen >= 6 the
       * hardware figures out by itself what the right compression mode is,
       * but we still need to know whether the instruction is compressed to
       * set up the source register regions appropriately.
       *
       * XXX - This is wrong for instructions that write a single register but
       *       read more than one which should strictly speaking be treated as
       *       compressed.  For instructions that don't write any registers it
       *       relies on the destination being a null register of the correct
       *       type and regioning so the instruction is considered compressed
       *       or not accordingly.
       */
      const bool compressed =
           inst->dst.component_size(inst->exec_size) > REG_SIZE;
      brw_set_default_compression(p, compressed);
      brw_set_default_group(p, inst->group);

      for (unsigned int i = 0; i < inst->sources; i++) {
         src[i] = brw_reg_from_fs_reg(devinfo, inst,
                                      &inst->src[i], compressed);
         /* The accumulator result appears to get used for the
          * conditional modifier generation.  When negating a UD
          * value, there is a 33rd bit generated for the sign in the
          * accumulator value, so now you can't check, for example,
          * equality with a 32-bit value.  See piglit fs-op-neg-uvec4.
          */
         assert(!inst->conditional_mod ||
                inst->src[i].type != BRW_REGISTER_TYPE_UD ||
                !inst->src[i].negate);
      }
      dst = brw_reg_from_fs_reg(devinfo, inst,
                                &inst->dst, compressed);

      brw_set_default_access_mode(p, BRW_ALIGN_1);
      brw_set_default_predicate_control(p, inst->predicate);
      brw_set_default_predicate_inverse(p, inst->predicate_inverse);
      /* On gen7 and above, hardware automatically adds the group onto the
       * flag subregister number.  On Sandy Bridge and older, we have to do it
       * ourselves.
       */
      const unsigned flag_subreg = inst->flag_subreg +
         (devinfo->gen >= 7 ? 0 : inst->group / 16);
      brw_set_default_flag_reg(p, flag_subreg / 2, flag_subreg % 2);
      brw_set_default_saturate(p, inst->saturate);
      brw_set_default_mask_control(p, inst->force_writemask_all);
      brw_set_default_acc_write_control(p, inst->writes_accumulator);

      unsigned exec_size = inst->exec_size;
      if (devinfo->gen == 7 && !devinfo->is_haswell &&
          (get_exec_type_size(inst) == 8 || type_sz(inst->dst.type) == 8)) {
         exec_size *= 2;
      }

      brw_set_default_exec_size(p, cvt(exec_size) - 1);

      assert(inst->force_writemask_all || inst->exec_size >= 4);
      assert(inst->force_writemask_all || inst->group % inst->exec_size == 0);
      assert(inst->base_mrf + inst->mlen <= BRW_MAX_MRF(devinfo->gen));
      assert(inst->mlen <= BRW_MAX_MSG_LENGTH);

      switch (inst->opcode) {
      case BRW_OPCODE_MOV:
         brw_MOV(p, dst, src[0]);
         break;
      case BRW_OPCODE_ADD:
         brw_ADD(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_MUL:
         brw_MUL(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_AVG:
         brw_AVG(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_MACH:
         brw_MACH(p, dst, src[0], src[1]);
         break;

      case BRW_OPCODE_LINE:
         brw_LINE(p, dst, src[0], src[1]);
         break;

      case BRW_OPCODE_MAD:
         assert(devinfo->gen >= 6);
         if (devinfo->gen < 10)
            brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_MAD(p, dst, src[0], src[1], src[2]);
         break;

      case BRW_OPCODE_LRP:
         assert(devinfo->gen >= 6 && devinfo->gen <= 10);
         if (devinfo->gen < 10)
            brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_LRP(p, dst, src[0], src[1], src[2]);
         break;

      case BRW_OPCODE_FRC:
         brw_FRC(p, dst, src[0]);
         break;
      case BRW_OPCODE_RNDD:
         brw_RNDD(p, dst, src[0]);
         break;
      case BRW_OPCODE_RNDE:
         brw_RNDE(p, dst, src[0]);
         break;
      case BRW_OPCODE_RNDZ:
         brw_RNDZ(p, dst, src[0]);
         break;

      case BRW_OPCODE_AND:
         brw_AND(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_OR:
         brw_OR(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_XOR:
         brw_XOR(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_NOT:
         brw_NOT(p, dst, src[0]);
         break;
      case BRW_OPCODE_ASR:
         brw_ASR(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_SHR:
         brw_SHR(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_SHL:
         brw_SHL(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_F32TO16:
         assert(devinfo->gen >= 7);
         brw_F32TO16(p, dst, src[0]);
         break;
      case BRW_OPCODE_F16TO32:
         assert(devinfo->gen >= 7);
         brw_F16TO32(p, dst, src[0]);
         break;
      case BRW_OPCODE_CMP:
         if (inst->exec_size >= 16 && devinfo->gen == 7 && !devinfo->is_haswell &&
             dst.file == BRW_ARCHITECTURE_REGISTER_FILE) {
            /* For unknown reasons the WaCMPInstFlagDepClearedEarly workaround
             * implemented in the compiler is not sufficient. Overriding the
             * type when the destination is the null register is necessary but
             * not sufficient by itself.
             */
            assert(dst.nr == BRW_ARF_NULL);
            dst.type = BRW_REGISTER_TYPE_D;
         }
         brw_CMP(p, dst, inst->conditional_mod, src[0], src[1]);
         break;
      case BRW_OPCODE_SEL:
         brw_SEL(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_CSEL:
         assert(devinfo->gen >= 8);
         if (devinfo->gen < 10)
            brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_CSEL(p, dst, src[0], src[1], src[2]);
         break;
      case BRW_OPCODE_BFREV:
         assert(devinfo->gen >= 7);
         brw_BFREV(p, retype(dst, BRW_REGISTER_TYPE_UD),
                   retype(src[0], BRW_REGISTER_TYPE_UD));
         break;
      case BRW_OPCODE_FBH:
         assert(devinfo->gen >= 7);
         brw_FBH(p, retype(dst, src[0].type), src[0]);
         break;
      case BRW_OPCODE_FBL:
         assert(devinfo->gen >= 7);
         brw_FBL(p, retype(dst, BRW_REGISTER_TYPE_UD),
                 retype(src[0], BRW_REGISTER_TYPE_UD));
         break;
      case BRW_OPCODE_LZD:
         brw_LZD(p, dst, src[0]);
         break;
      case BRW_OPCODE_CBIT:
         assert(devinfo->gen >= 7);
         brw_CBIT(p, retype(dst, BRW_REGISTER_TYPE_UD),
                  retype(src[0], BRW_REGISTER_TYPE_UD));
         break;
      case BRW_OPCODE_ADDC:
         assert(devinfo->gen >= 7);
         brw_ADDC(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_SUBB:
         assert(devinfo->gen >= 7);
         brw_SUBB(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_MAC:
         brw_MAC(p, dst, src[0], src[1]);
         break;

      case BRW_OPCODE_BFE:
         assert(devinfo->gen >= 7);
         if (devinfo->gen < 10)
            brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_BFE(p, dst, src[0], src[1], src[2]);
         break;

      case BRW_OPCODE_BFI1:
         assert(devinfo->gen >= 7);
         brw_BFI1(p, dst, src[0], src[1]);
         break;
      case BRW_OPCODE_BFI2:
         assert(devinfo->gen >= 7);
         if (devinfo->gen < 10)
            brw_set_default_access_mode(p, BRW_ALIGN_16);
         brw_BFI2(p, dst, src[0], src[1], src[2]);
         break;

      case BRW_OPCODE_IF:
         if (inst->src[0].file != BAD_FILE) {
            /* The instruction has an embedded compare (only allowed on gen6) */
            assert(devinfo->gen == 6);
            gen6_IF(p, inst->conditional_mod, src[0], src[1]);
         } else {
            brw_IF(p, brw_get_default_exec_size(p));
         }
         break;

      case BRW_OPCODE_ELSE:
         brw_ELSE(p);
         break;
      case BRW_OPCODE_ENDIF:
         brw_ENDIF(p);
         break;

      case BRW_OPCODE_DO:
         brw_DO(p, brw_get_default_exec_size(p));
         break;

      case BRW_OPCODE_BREAK:
         brw_BREAK(p);
         break;
      case BRW_OPCODE_CONTINUE:
         brw_CONT(p);
         break;

      case BRW_OPCODE_WHILE:
         brw_WHILE(p);
         loop_count++;
         break;

      case SHADER_OPCODE_RCP:
      case SHADER_OPCODE_RSQ:
      case SHADER_OPCODE_SQRT:
      case SHADER_OPCODE_EXP2:
      case SHADER_OPCODE_LOG2:
      case SHADER_OPCODE_SIN:
      case SHADER_OPCODE_COS:
         assert(inst->conditional_mod == BRW_CONDITIONAL_NONE);
         if (devinfo->gen >= 6) {
            assert(inst->mlen == 0);
            assert(devinfo->gen >= 7 || inst->exec_size == 8);
            gen6_math(p, dst, brw_math_function(inst->opcode),
                      src[0], brw_null_reg());
         } else {
            assert(inst->mlen >= 1);
            assert(devinfo->gen == 5 || devinfo->is_g4x || inst->exec_size == 8);
            gen4_math(p, dst,
                      brw_math_function(inst->opcode),
                      inst->base_mrf, src[0],
                      BRW_MATH_PRECISION_FULL);
         }
         break;
      case SHADER_OPCODE_INT_QUOTIENT:
      case SHADER_OPCODE_INT_REMAINDER:
      case SHADER_OPCODE_POW:
         assert(inst->conditional_mod == BRW_CONDITIONAL_NONE);
         if (devinfo->gen >= 6) {
            assert(inst->mlen == 0);
            assert((devinfo->gen >= 7 && inst->opcode == SHADER_OPCODE_POW) ||
                   inst->exec_size == 8);
            gen6_math(p, dst, brw_math_function(inst->opcode), src[0], src[1]);
         } else {
            assert(inst->mlen >= 1);
            assert(inst->exec_size == 8);
            gen4_math(p, dst, brw_math_function(inst->opcode),
                      inst->base_mrf, src[0],
                      BRW_MATH_PRECISION_FULL);
         }
         break;
      case FS_OPCODE_LINTERP:
         multiple_instructions_emitted = generate_linterp(inst, dst, src);
         break;
      case FS_OPCODE_PIXEL_X:
         assert(src[0].type == BRW_REGISTER_TYPE_UW);
         src[0].subnr = 0 * type_sz(src[0].type);
         brw_MOV(p, dst, stride(src[0], 8, 4, 1));
         break;
      case FS_OPCODE_PIXEL_Y:
         assert(src[0].type == BRW_REGISTER_TYPE_UW);
         src[0].subnr = 4 * type_sz(src[0].type);
         brw_MOV(p, dst, stride(src[0], 8, 4, 1));
         break;

      case SHADER_OPCODE_SEND:
         generate_send(inst, dst, src[0], src[1], src[2],
                       inst->ex_mlen > 0 ? src[3] : brw_null_reg());
         break;

      case SHADER_OPCODE_GET_BUFFER_SIZE:
         generate_get_buffer_size(inst, dst, src[0], src[1]);
         break;
      case SHADER_OPCODE_TEX:
      case FS_OPCODE_TXB:
      case SHADER_OPCODE_TXD:
      case SHADER_OPCODE_TXF:
      case SHADER_OPCODE_TXF_CMS:
      case SHADER_OPCODE_TXL:
      case SHADER_OPCODE_TXS:
      case SHADER_OPCODE_LOD:
      case SHADER_OPCODE_TG4:
      case SHADER_OPCODE_SAMPLEINFO:
         assert(inst->src[0].file == BAD_FILE);
         generate_tex(inst, dst, src[1], src[2]);
         break;

      case FS_OPCODE_DDX_COARSE:
      case FS_OPCODE_DDX_FINE:
         generate_ddx(inst, dst, src[0]);
         break;
      case FS_OPCODE_DDY_COARSE:
      case FS_OPCODE_DDY_FINE:
         generate_ddy(inst, dst, src[0]);
         break;

      case SHADER_OPCODE_GEN4_SCRATCH_WRITE:
         generate_scratch_write(inst, src[0]);
         spill_count++;
         break;

      case SHADER_OPCODE_GEN4_SCRATCH_READ:
         generate_scratch_read(inst, dst);
         fill_count++;
         break;

      case SHADER_OPCODE_GEN7_SCRATCH_READ:
         generate_scratch_read_gen7(inst, dst);
         fill_count++;
         break;

      case SHADER_OPCODE_MOV_INDIRECT:
         generate_mov_indirect(inst, dst, src[0], src[1]);
         break;

      case SHADER_OPCODE_URB_READ_SIMD8:
      case SHADER_OPCODE_URB_READ_SIMD8_PER_SLOT:
         generate_urb_read(inst, dst, src[0]);
         break;

      case SHADER_OPCODE_URB_WRITE_SIMD8:
      case SHADER_OPCODE_URB_WRITE_SIMD8_PER_SLOT:
      case SHADER_OPCODE_URB_WRITE_SIMD8_MASKED:
      case SHADER_OPCODE_URB_WRITE_SIMD8_MASKED_PER_SLOT:
         generate_urb_write(inst, src[0]);
         break;

      case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD:
         assert(inst->force_writemask_all);
         generate_uniform_pull_constant_load(inst, dst, src[0], src[1]);
         break;

      case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD_GEN7:
         assert(inst->force_writemask_all);
         generate_uniform_pull_constant_load_gen7(inst, dst, src[0], src[1]);
         break;

      case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_GEN4:
         generate_varying_pull_constant_load_gen4(inst, dst, src[0]);
         break;

      case FS_OPCODE_REP_FB_WRITE:
      case FS_OPCODE_FB_WRITE:
         generate_fb_write(inst, src[0]);
         break;

      case FS_OPCODE_FB_READ:
         generate_fb_read(inst, dst, src[0]);
         break;

      case FS_OPCODE_DISCARD_JUMP:
         generate_discard_jump(inst);
         break;

      case SHADER_OPCODE_SHADER_TIME_ADD:
         generate_shader_time_add(inst, src[0], src[1], src[2]);
         break;

      case SHADER_OPCODE_MEMORY_FENCE:
         assert(src[1].file == BRW_IMMEDIATE_VALUE);
         brw_memory_fence(p, dst, src[0], BRW_OPCODE_SEND, src[1].ud);
         break;

      case SHADER_OPCODE_INTERLOCK:
         assert(devinfo->gen >= 9);
         /* The interlock is basically a memory fence issued via sendc */
         brw_memory_fence(p, dst, src[0], BRW_OPCODE_SENDC, false);
         break;

      case SHADER_OPCODE_FIND_LIVE_CHANNEL: {
         const struct brw_reg mask =
            brw_stage_has_packed_dispatch(devinfo, stage,
                                          prog_data) ? brw_imm_ud(~0u) :
            stage == MESA_SHADER_FRAGMENT ? brw_vmask_reg() :
            brw_dmask_reg();
         brw_find_live_channel(p, dst, mask);
         break;
      }

      case SHADER_OPCODE_BROADCAST:
         assert(inst->force_writemask_all);
         brw_broadcast(p, dst, src[0], src[1]);
         break;

      case SHADER_OPCODE_SHUFFLE:
         generate_shuffle(inst, dst, src[0], src[1]);
         break;

      case SHADER_OPCODE_SEL_EXEC:
         assert(inst->force_writemask_all);
         brw_set_default_mask_control(p, BRW_MASK_DISABLE);
         brw_MOV(p, dst, src[1]);
         brw_set_default_mask_control(p, BRW_MASK_ENABLE);
         brw_MOV(p, dst, src[0]);
         break;

      case SHADER_OPCODE_QUAD_SWIZZLE:
         assert(src[1].file == BRW_IMMEDIATE_VALUE);
         assert(src[1].type == BRW_REGISTER_TYPE_UD);
         generate_quad_swizzle(inst, dst, src[0], src[1].ud);
         break;

      case SHADER_OPCODE_CLUSTER_BROADCAST: {
         assert(src[0].type == dst.type);
         assert(!src[0].negate && !src[0].abs);
         assert(src[1].file == BRW_IMMEDIATE_VALUE);
         assert(src[1].type == BRW_REGISTER_TYPE_UD);
         assert(src[2].file == BRW_IMMEDIATE_VALUE);
         assert(src[2].type == BRW_REGISTER_TYPE_UD);
         const unsigned component = src[1].ud;
         const unsigned cluster_size = src[2].ud;
         struct brw_reg strided = stride(suboffset(src[0], component),
                                         cluster_size, cluster_size, 0);
         if (type_sz(src[0].type) > 4 &&
             (devinfo->is_cherryview || gen_device_info_is_9lp(devinfo))) {
            /* IVB has an issue (which we found empirically) where it reads
             * two address register components per channel for indirectly
             * addressed 64-bit sources.
             *
             * From the Cherryview PRM Vol 7. "Register Region Restrictions":
             *
             *    "When source or destination datatype is 64b or operation is
             *    integer DWord multiply, indirect addressing must not be
             *    used."
             *
             * To work around both of these, we do two integer MOVs insead of
             * one 64-bit MOV.  Because no double value should ever cross a
             * register boundary, it's safe to use the immediate offset in the
             * indirect here to handle adding 4 bytes to the offset and avoid
             * the extra ADD to the register file.
             */
            brw_MOV(p, subscript(dst, BRW_REGISTER_TYPE_D, 0),
                       subscript(strided, BRW_REGISTER_TYPE_D, 0));
            brw_MOV(p, subscript(dst, BRW_REGISTER_TYPE_D, 1),
                       subscript(strided, BRW_REGISTER_TYPE_D, 1));
         } else {
            brw_MOV(p, dst, strided);
         }
         break;
      }

      case FS_OPCODE_SET_SAMPLE_ID:
         generate_set_sample_id(inst, dst, src[0], src[1]);
         break;

      case FS_OPCODE_PACK_HALF_2x16_SPLIT:
          generate_pack_half_2x16_split(inst, dst, src[0], src[1]);
          break;

      case FS_OPCODE_PLACEHOLDER_HALT:
         /* This is the place where the final HALT needs to be inserted if
          * we've emitted any discards.  If not, this will emit no code.
          */
         if (!patch_discard_jumps_to_fb_writes()) {
            if (unlikely(debug_flag)) {
               disasm_info->use_tail = true;
            }
         }
         break;

      case FS_OPCODE_INTERPOLATE_AT_SAMPLE:
         generate_pixel_interpolator_query(inst, dst, src[0], src[1],
                                           GEN7_PIXEL_INTERPOLATOR_LOC_SAMPLE);
         break;

      case FS_OPCODE_INTERPOLATE_AT_SHARED_OFFSET:
         generate_pixel_interpolator_query(inst, dst, src[0], src[1],
                                           GEN7_PIXEL_INTERPOLATOR_LOC_SHARED_OFFSET);
         break;

      case FS_OPCODE_INTERPOLATE_AT_PER_SLOT_OFFSET:
         generate_pixel_interpolator_query(inst, dst, src[0], src[1],
                                           GEN7_PIXEL_INTERPOLATOR_LOC_PER_SLOT_OFFSET);
         break;

      case CS_OPCODE_CS_TERMINATE:
         generate_cs_terminate(inst, src[0]);
         break;

      case SHADER_OPCODE_BARRIER:
         generate_barrier(inst, src[0]);
         break;

      case BRW_OPCODE_DIM:
         assert(devinfo->is_haswell);
         assert(src[0].type == BRW_REGISTER_TYPE_DF);
         assert(dst.type == BRW_REGISTER_TYPE_DF);
         brw_DIM(p, dst, retype(src[0], BRW_REGISTER_TYPE_F));
         break;

      case SHADER_OPCODE_RND_MODE:
         assert(src[0].file == BRW_IMMEDIATE_VALUE);
         brw_rounding_mode(p, (brw_rnd_mode) src[0].d);
         break;

      default:
         unreachable("Unsupported opcode");

      case SHADER_OPCODE_LOAD_PAYLOAD:
         unreachable("Should be lowered by lower_load_payload()");
      }

      if (multiple_instructions_emitted)
         continue;

      if (inst->no_dd_clear || inst->no_dd_check || inst->conditional_mod) {
         assert(p->next_insn_offset == last_insn_offset + 16 ||
                !"conditional_mod, no_dd_check, or no_dd_clear set for IR "
                 "emitting more than 1 instruction");

         brw_inst *last = &p->store[last_insn_offset / 16];

         if (inst->conditional_mod)
            brw_inst_set_cond_modifier(p->devinfo, last, inst->conditional_mod);
         brw_inst_set_no_dd_clear(p->devinfo, last, inst->no_dd_clear);
         brw_inst_set_no_dd_check(p->devinfo, last, inst->no_dd_check);
      }
   }

   brw_set_uip_jip(p, start_offset);

   /* end of program sentinel */
   disasm_new_inst_group(disasm_info, p->next_insn_offset);

#ifndef NDEBUG
   bool validated =
#else
   if (unlikely(debug_flag))
#endif
      brw_validate_instructions(devinfo, p->store,
                                start_offset,
                                p->next_insn_offset,
                                disasm_info);

   int before_size = p->next_insn_offset - start_offset;
   brw_compact_instructions(p, start_offset, disasm_info);
   int after_size = p->next_insn_offset - start_offset;

   if (unlikely(debug_flag)) {
      fprintf(stderr, "Native code for %s\n"
              "SIMD%d shader: %d instructions. %d loops. %u cycles. %d:%d spills:fills. Promoted %u constants. Compacted %d to %d"
              " bytes (%.0f%%)\n",
              shader_name, dispatch_width, before_size / 16, loop_count, cfg->cycle_count,
              spill_count, fill_count, promoted_constants, before_size, after_size,
              100.0f * (before_size - after_size) / before_size);

      dump_assembly(p->store, disasm_info);
   }
   ralloc_free(disasm_info);
   assert(validated);

   compiler->shader_debug_log(log_data,
                              "%s SIMD%d shader: %d inst, %d loops, %u cycles, "
                              "%d:%d spills:fills, Promoted %u constants, "
                              "compacted %d to %d bytes.",
                              _mesa_shader_stage_to_abbrev(stage),
                              dispatch_width, before_size / 16,
                              loop_count, cfg->cycle_count, spill_count,
                              fill_count, promoted_constants, before_size,
                              after_size);

   return start_offset;
}

const unsigned *
fs_generator::get_assembly()
{
   return brw_get_program(p, &prog_data->program_size);
}