i965: Add generate() handling for AND, OR, XOR.

[mesa.git] / src / mesa / drivers / dri / i965 / brw_fs.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.
 *
 * Authors:
 *    Eric Anholt <eric@anholt.net>
 *
 */

extern "C" {

#include <sys/types.h>
/* Evil hack for using libdrm in a c++ compiler. */
#define virtual virt
#include "i915_drm.h"
#include "intel_bufmgr.h"
#undef virtual

#include "main/macros.h"
#include "main/shaderobj.h"
#include "program/prog_parameter.h"
#include "program/prog_print.h"
#include "program/prog_optimize.h"
#include "program/hash_table.h"
#include "brw_context.h"
#include "brw_eu.h"
#include "brw_wm.h"
#include "talloc.h"
}
#include "../glsl/glsl_types.h"
#include "../glsl/ir_optimization.h"
#include "../glsl/ir_print_visitor.h"

enum register_file {
   ARF = BRW_ARCHITECTURE_REGISTER_FILE,
   GRF = BRW_GENERAL_REGISTER_FILE,
   MRF = BRW_MESSAGE_REGISTER_FILE,
   IMM = BRW_IMMEDIATE_VALUE,
   FIXED_HW_REG, /* a struct brw_reg */
   UNIFORM, /* prog_data->params[hw_reg] */
   BAD_FILE
};

enum fs_opcodes {
   FS_OPCODE_FB_WRITE = 256,
   FS_OPCODE_RCP,
   FS_OPCODE_RSQ,
   FS_OPCODE_SQRT,
   FS_OPCODE_EXP2,
   FS_OPCODE_LOG2,
   FS_OPCODE_POW,
   FS_OPCODE_SIN,
   FS_OPCODE_COS,
   FS_OPCODE_DDX,
   FS_OPCODE_DDY,
   FS_OPCODE_LINTERP,
};

static int using_new_fs = -1;

struct gl_shader *
brw_new_shader(GLcontext *ctx, GLuint name, GLuint type)
{
   struct brw_shader *shader;

   shader = talloc_zero(NULL, struct brw_shader);
   if (shader) {
      shader->base.Type = type;
      shader->base.Name = name;
      _mesa_init_shader(ctx, &shader->base);
   }

   return &shader->base;
}

struct gl_shader_program *
brw_new_shader_program(GLcontext *ctx, GLuint name)
{
   struct brw_shader_program *prog;
   prog = talloc_zero(NULL, struct brw_shader_program);
   if (prog) {
      prog->base.Name = name;
      _mesa_init_shader_program(ctx, &prog->base);
   }
   return &prog->base;
}

GLboolean
brw_compile_shader(GLcontext *ctx, struct gl_shader *shader)
{
   if (!_mesa_ir_compile_shader(ctx, shader))
      return GL_FALSE;

   return GL_TRUE;
}

GLboolean
brw_link_shader(GLcontext *ctx, struct gl_shader_program *prog)
{
   if (using_new_fs == -1)
      using_new_fs = getenv("INTEL_NEW_FS") != NULL;

   for (unsigned i = 0; i < prog->_NumLinkedShaders; i++) {
      struct brw_shader *shader = (struct brw_shader *)prog->_LinkedShaders[i];

      if (using_new_fs && shader->base.Type == GL_FRAGMENT_SHADER) {
         void *mem_ctx = talloc_new(NULL);
         bool progress;

         if (shader->ir)
            talloc_free(shader->ir);
         shader->ir = new(shader) exec_list;
         clone_ir_list(mem_ctx, shader->ir, shader->base.ir);

         do_mat_op_to_vec(shader->ir);
         do_div_to_mul_rcp(shader->ir);
         do_sub_to_add_neg(shader->ir);
         do_explog_to_explog2(shader->ir);

         brw_do_channel_expressions(shader->ir);
         brw_do_vector_splitting(shader->ir);

         do {
            progress = false;

            progress = do_common_optimization(shader->ir, true) || progress;
         } while (progress);

         validate_ir_tree(shader->ir);

         reparent_ir(shader->ir, shader->ir);
         talloc_free(mem_ctx);
      }
   }

   if (!_mesa_ir_link_shader(ctx, prog))
      return GL_FALSE;

   return GL_TRUE;
}

static int
type_size(const struct glsl_type *type)
{
   unsigned int size, i;

   switch (type->base_type) {
   case GLSL_TYPE_UINT:
   case GLSL_TYPE_INT:
   case GLSL_TYPE_FLOAT:
   case GLSL_TYPE_BOOL:
      return type->components();
   case GLSL_TYPE_ARRAY:
      /* FINISHME: uniform/varying arrays. */
      return type_size(type->fields.array) * type->length;
   case GLSL_TYPE_STRUCT:
      size = 0;
      for (i = 0; i < type->length; i++) {
         size += type_size(type->fields.structure[i].type);
      }
      return size;
   case GLSL_TYPE_SAMPLER:
      /* Samplers take up no register space, since they're baked in at
       * link time.
       */
      return 0;
   default:
      assert(!"not reached");
      return 0;
   }
}

class fs_reg {
public:
   /* Callers of this talloc-based new need not call delete. It's
    * easier to just talloc_free 'ctx' (or any of its ancestors). */
   static void* operator new(size_t size, void *ctx)
   {
      void *node;

      node = talloc_size(ctx, size);
      assert(node != NULL);

      return node;
   }

   /** Generic unset register constructor. */
   fs_reg()
   {
      this->file = BAD_FILE;
      this->reg = 0;
      this->reg_offset = 0;
      this->hw_reg = -1;
      this->negate = 0;
      this->abs = 0;
   }

   /** Immediate value constructor. */
   fs_reg(float f)
   {
      this->file = IMM;
      this->reg = 0;
      this->hw_reg = 0;
      this->type = BRW_REGISTER_TYPE_F;
      this->imm.f = f;
      this->negate = 0;
      this->abs = 0;
   }

   /** Immediate value constructor. */
   fs_reg(int32_t i)
   {
      this->file = IMM;
      this->reg = 0;
      this->hw_reg = 0;
      this->type = BRW_REGISTER_TYPE_D;
      this->imm.i = i;
      this->negate = 0;
      this->abs = 0;
   }

   /** Immediate value constructor. */
   fs_reg(uint32_t u)
   {
      this->file = IMM;
      this->reg = 0;
      this->hw_reg = 0;
      this->type = BRW_REGISTER_TYPE_UD;
      this->imm.u = u;
      this->negate = 0;
      this->abs = 0;
   }

   /** Fixed brw_reg Immediate value constructor. */
   fs_reg(struct brw_reg fixed_hw_reg)
   {
      this->file = FIXED_HW_REG;
      this->fixed_hw_reg = fixed_hw_reg;
      this->reg = 0;
      this->hw_reg = 0;
      this->type = fixed_hw_reg.type;
      this->negate = 0;
      this->abs = 0;
   }

   fs_reg(enum register_file file, int hw_reg);
   fs_reg(class fs_visitor *v, const struct glsl_type *type);

   /** Register file: ARF, GRF, MRF, IMM. */
   enum register_file file;
   /** Abstract register number.  0 = fixed hw reg */
   int reg;
   /** Offset within the abstract register. */
   int reg_offset;
   /** HW register number.  Generally unset until register allocation. */
   int hw_reg;
   /** Register type.  BRW_REGISTER_TYPE_* */
   int type;
   bool negate;
   bool abs;
   struct brw_reg fixed_hw_reg;

   /** Value for file == BRW_IMMMEDIATE_FILE */
   union {
      int32_t i;
      uint32_t u;
      float f;
   } imm;
};

static const fs_reg reg_undef;
static const fs_reg reg_null(ARF, BRW_ARF_NULL);

class fs_inst : public exec_node {
public:
   /* Callers of this talloc-based new need not call delete. It's
    * easier to just talloc_free 'ctx' (or any of its ancestors). */
   static void* operator new(size_t size, void *ctx)
   {
      void *node;

      node = talloc_zero_size(ctx, size);
      assert(node != NULL);

      return node;
   }

   fs_inst()
   {
      this->opcode = BRW_OPCODE_NOP;
      this->saturate = false;
      this->conditional_mod = BRW_CONDITIONAL_NONE;
      this->predicated = false;
   }

   fs_inst(int opcode)
   {
      this->opcode = opcode;
      this->saturate = false;
      this->conditional_mod = BRW_CONDITIONAL_NONE;
      this->predicated = false;
   }

   fs_inst(int opcode, fs_reg dst, fs_reg src0)
   {
      this->opcode = opcode;
      this->dst = dst;
      this->src[0] = src0;
      this->saturate = false;
      this->conditional_mod = BRW_CONDITIONAL_NONE;
      this->predicated = false;
   }

   fs_inst(int opcode, fs_reg dst, fs_reg src0, fs_reg src1)
   {
      this->opcode = opcode;
      this->dst = dst;
      this->src[0] = src0;
      this->src[1] = src1;
      this->saturate = false;
      this->conditional_mod = BRW_CONDITIONAL_NONE;
      this->predicated = false;
   }

   fs_inst(int opcode, fs_reg dst, fs_reg src0, fs_reg src1, fs_reg src2)
   {
      this->opcode = opcode;
      this->dst = dst;
      this->src[0] = src0;
      this->src[1] = src1;
      this->src[2] = src2;
      this->saturate = false;
      this->conditional_mod = BRW_CONDITIONAL_NONE;
      this->predicated = false;
   }

   int opcode; /* BRW_OPCODE_* or FS_OPCODE_* */
   fs_reg dst;
   fs_reg src[3];
   bool saturate;
   bool predicated;
   int conditional_mod; /**< BRW_CONDITIONAL_* */

   /** @{
    * Annotation for the generated IR.  One of the two can be set.
    */
   ir_instruction *ir;
   const char *annotation;
   /** @} */
};

class fs_visitor : public ir_visitor
{
public:

   fs_visitor(struct brw_wm_compile *c, struct brw_shader *shader)
   {
      this->c = c;
      this->p = &c->func;
      this->brw = p->brw;
      this->intel = &brw->intel;
      this->ctx = &intel->ctx;
      this->mem_ctx = talloc_new(NULL);
      this->shader = shader;
      this->fail = false;
      this->next_abstract_grf = 1;
      this->variable_ht = hash_table_ctor(0,
                                          hash_table_pointer_hash,
                                          hash_table_pointer_compare);

      this->frag_color = NULL;
      this->frag_data = NULL;
      this->frag_depth = NULL;
      this->first_non_payload_grf = 0;

      this->current_annotation = NULL;
      this->annotation_string = NULL;
      this->annotation_ir = NULL;
   }
   ~fs_visitor()
   {
      talloc_free(this->mem_ctx);
      hash_table_dtor(this->variable_ht);
   }

   fs_reg *variable_storage(ir_variable *var);

   void visit(ir_variable *ir);
   void visit(ir_assignment *ir);
   void visit(ir_dereference_variable *ir);
   void visit(ir_dereference_record *ir);
   void visit(ir_dereference_array *ir);
   void visit(ir_expression *ir);
   void visit(ir_texture *ir);
   void visit(ir_if *ir);
   void visit(ir_constant *ir);
   void visit(ir_swizzle *ir);
   void visit(ir_return *ir);
   void visit(ir_loop *ir);
   void visit(ir_loop_jump *ir);
   void visit(ir_discard *ir);
   void visit(ir_call *ir);
   void visit(ir_function *ir);
   void visit(ir_function_signature *ir);

   fs_inst *emit(fs_inst inst);
   void assign_curb_setup();
   void assign_urb_setup();
   void assign_regs();
   void generate_code();
   void generate_fb_write(fs_inst *inst);
   void generate_linterp(fs_inst *inst, struct brw_reg dst,
                         struct brw_reg *src);
   void generate_math(fs_inst *inst, struct brw_reg dst, struct brw_reg *src);

   void emit_dummy_fs();
   void emit_interpolation();
   void emit_pinterp(int location);
   void emit_fb_writes();

   struct brw_reg interp_reg(int location, int channel);

   struct brw_context *brw;
   struct intel_context *intel;
   GLcontext *ctx;
   struct brw_wm_compile *c;
   struct brw_compile *p;
   struct brw_shader *shader;
   void *mem_ctx;
   exec_list instructions;
   int next_abstract_grf;
   struct hash_table *variable_ht;
   ir_variable *frag_color, *frag_data, *frag_depth;
   int first_non_payload_grf;

   /** @{ debug annotation info */
   const char *current_annotation;
   ir_instruction *base_ir;
   const char **annotation_string;
   ir_instruction **annotation_ir;
   /** @} */

   bool fail;

   /* Result of last visit() method. */
   fs_reg result;

   fs_reg pixel_x;
   fs_reg pixel_y;
   fs_reg pixel_w;
   fs_reg delta_x;
   fs_reg delta_y;
   fs_reg interp_attrs[64];

   int grf_used;

};

/** Fixed HW reg constructor. */
fs_reg::fs_reg(enum register_file file, int hw_reg)
{
   this->file = file;
   this->reg = 0;
   this->reg_offset = 0;
   this->hw_reg = hw_reg;
   this->type = BRW_REGISTER_TYPE_F;
   this->negate = 0;
   this->abs = 0;
}

/** Automatic reg constructor. */
fs_reg::fs_reg(class fs_visitor *v, const struct glsl_type *type)
{
   this->file = GRF;
   this->reg = v->next_abstract_grf;
   this->reg_offset = 0;
   v->next_abstract_grf += type_size(type);
   this->hw_reg = -1;
   this->negate = 0;
   this->abs = 0;

   switch (type->base_type) {
   case GLSL_TYPE_FLOAT:
      this->type = BRW_REGISTER_TYPE_F;
      break;
   case GLSL_TYPE_INT:
   case GLSL_TYPE_BOOL:
      this->type = BRW_REGISTER_TYPE_D;
      break;
   case GLSL_TYPE_UINT:
      this->type = BRW_REGISTER_TYPE_UD;
      break;
   default:
      assert(!"not reached");
      this->type =  BRW_REGISTER_TYPE_F;
      break;
   }
}

fs_reg *
fs_visitor::variable_storage(ir_variable *var)
{
   return (fs_reg *)hash_table_find(this->variable_ht, var);
}

void
fs_visitor::visit(ir_variable *ir)
{
   fs_reg *reg = NULL;

   if (strcmp(ir->name, "gl_FragColor") == 0) {
      this->frag_color = ir;
   } else if (strcmp(ir->name, "gl_FragData") == 0) {
      this->frag_data = ir;
   } else if (strcmp(ir->name, "gl_FragDepth") == 0) {
      this->frag_depth = ir;
      assert(!"FINISHME: this hangs currently.");
   }

   if (ir->mode == ir_var_in) {
      reg = &this->interp_attrs[ir->location];
   }

   if (ir->mode == ir_var_uniform) {
      const float *vec_values;
      int param_index = c->prog_data.nr_params;

      /* FINISHME: This is wildly incomplete. */
      assert(ir->type->is_scalar() || ir->type->is_vector());

      const struct gl_program *fp = &this->brw->fragment_program->Base;
      /* Our support for uniforms is piggy-backed on the struct
       * gl_fragment_program, because that's where the values actually
       * get stored, rather than in some global gl_shader_program uniform
       * store.
       */
      vec_values = fp->Parameters->ParameterValues[ir->location];
      for (unsigned int i = 0; i < ir->type->vector_elements; i++) {
         c->prog_data.param[c->prog_data.nr_params++] = &vec_values[i];
      }

      reg = new(this->mem_ctx) fs_reg(UNIFORM, param_index);
   }

   if (!reg)
      reg = new(this->mem_ctx) fs_reg(this, ir->type);

   hash_table_insert(this->variable_ht, reg, ir);
}

void
fs_visitor::visit(ir_dereference_variable *ir)
{
   fs_reg *reg = variable_storage(ir->var);
   this->result = *reg;
}

void
fs_visitor::visit(ir_dereference_record *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_dereference_array *ir)
{
   ir_constant *index;
   int element_size;

   ir->array->accept(this);
   index = ir->array_index->as_constant();

   if (ir->type->is_matrix()) {
      element_size = ir->type->vector_elements;
   } else {
      element_size = type_size(ir->type);
   }

   if (index) {
      assert(this->result.file == UNIFORM ||
             (this->result.file == GRF &&
              this->result.reg != 0));
      this->result.reg_offset += index->value.i[0] * element_size;
   } else {
      assert(!"FINISHME: non-constant matrix column");
   }
}

void
fs_visitor::visit(ir_expression *ir)
{
   unsigned int operand;
   fs_reg op[2], temp;
   fs_reg result;
   fs_inst *inst;

   for (operand = 0; operand < ir->get_num_operands(); operand++) {
      ir->operands[operand]->accept(this);
      if (this->result.file == BAD_FILE) {
         ir_print_visitor v;
         printf("Failed to get tree for expression operand:\n");
         ir->operands[operand]->accept(&v);
         this->fail = true;
      }
      op[operand] = this->result;

      /* Matrix expression operands should have been broken down to vector
       * operations already.
       */
      assert(!ir->operands[operand]->type->is_matrix());
      /* And then those vector operands should have been broken down to scalar.
       */
      assert(!ir->operands[operand]->type->is_vector());
   }

   /* Storage for our result.  If our result goes into an assignment, it will
    * just get copy-propagated out, so no worries.
    */
   this->result = fs_reg(this, ir->type);

   switch (ir->operation) {
   case ir_unop_logic_not:
      emit(fs_inst(BRW_OPCODE_ADD, this->result, op[0], fs_reg(-1)));
      break;
   case ir_unop_neg:
      this->result = op[0];
      op[0].negate = ~op[0].negate;
      break;
   case ir_unop_abs:
      this->result = op[0];
      op[0].abs = true;
      break;
   case ir_unop_sign:
      temp = fs_reg(this, ir->type);

      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], fs_reg(0.0f)));
      inst->conditional_mod = BRW_CONDITIONAL_G;

      inst = emit(fs_inst(BRW_OPCODE_CMP, temp, op[0], fs_reg(0.0f)));
      inst->conditional_mod = BRW_CONDITIONAL_L;

      temp.negate = true;
      emit(fs_inst(BRW_OPCODE_ADD, this->result, this->result, temp));

      break;
   case ir_unop_rcp:
      emit(fs_inst(FS_OPCODE_RCP, this->result, op[0]));
      break;

   case ir_unop_exp2:
      emit(fs_inst(FS_OPCODE_EXP2, this->result, op[0]));
      break;
   case ir_unop_log2:
      emit(fs_inst(FS_OPCODE_LOG2, this->result, op[0]));
      break;
   case ir_unop_exp:
   case ir_unop_log:
      assert(!"not reached: should be handled by ir_explog_to_explog2");
      break;
   case ir_unop_sin:
      emit(fs_inst(FS_OPCODE_SIN, this->result, op[0]));
      break;
   case ir_unop_cos:
      emit(fs_inst(FS_OPCODE_COS, this->result, op[0]));
      break;

   case ir_unop_dFdx:
      emit(fs_inst(FS_OPCODE_DDX, this->result, op[0]));
      break;
   case ir_unop_dFdy:
      emit(fs_inst(FS_OPCODE_DDY, this->result, op[0]));
      break;

   case ir_binop_add:
      emit(fs_inst(BRW_OPCODE_ADD, this->result, op[0], op[1]));
      break;
   case ir_binop_sub:
      assert(!"not reached: should be handled by ir_sub_to_add_neg");
      break;

   case ir_binop_mul:
      emit(fs_inst(BRW_OPCODE_MUL, this->result, op[0], op[1]));
      break;
   case ir_binop_div:
      assert(!"not reached: should be handled by ir_div_to_mul_rcp");
      break;
   case ir_binop_mod:
      assert(!"ir_binop_mod should have been converted to b * fract(a/b)");
      break;

   case ir_binop_less:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_L;
      break;
   case ir_binop_greater:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_G;
      break;
   case ir_binop_lequal:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_LE;
      break;
   case ir_binop_gequal:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_GE;
      break;
   case ir_binop_equal:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_Z;
      break;
   case ir_binop_nequal:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_NZ;
      break;

   case ir_binop_logic_xor:
      emit(fs_inst(BRW_OPCODE_XOR, this->result, op[0], op[1]));
      break;

   case ir_binop_logic_or:
      emit(fs_inst(BRW_OPCODE_OR, this->result, op[0], op[1]));
      break;

   case ir_binop_logic_and:
      emit(fs_inst(BRW_OPCODE_AND, this->result, op[0], op[1]));
      break;

   case ir_binop_dot:
   case ir_binop_cross:
   case ir_unop_any:
      assert(!"not reached: should be handled by brw_channel_expressions");
      break;

   case ir_unop_sqrt:
      emit(fs_inst(FS_OPCODE_SQRT, this->result, op[0]));
      break;

   case ir_unop_rsq:
      emit(fs_inst(FS_OPCODE_RSQ, this->result, op[0]));
      break;

   case ir_unop_i2f:
   case ir_unop_b2f:
   case ir_unop_b2i:
      emit(fs_inst(BRW_OPCODE_MOV, this->result, op[0]));
      break;
   case ir_unop_f2i:
      emit(fs_inst(BRW_OPCODE_RNDZ, this->result, op[0]));
      break;
   case ir_unop_f2b:
   case ir_unop_i2b:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], fs_reg(0.0f)));
      inst->conditional_mod = BRW_CONDITIONAL_NZ;

   case ir_unop_trunc:
      emit(fs_inst(BRW_OPCODE_RNDD, this->result, op[0]));
      break;
   case ir_unop_ceil:
      op[0].negate = ~op[0].negate;
      inst = emit(fs_inst(BRW_OPCODE_RNDD, this->result, op[0]));
      this->result.negate = true;
      break;
   case ir_unop_floor:
      inst = emit(fs_inst(BRW_OPCODE_RNDD, this->result, op[0]));
      break;
   case ir_unop_fract:
      inst = emit(fs_inst(BRW_OPCODE_FRC, this->result, op[0]));
      break;

   case ir_binop_min:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_L;

      inst = emit(fs_inst(BRW_OPCODE_SEL, this->result, op[0], op[1]));
      inst->predicated = true;
      break;
   case ir_binop_max:
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, op[0], op[1]));
      inst->conditional_mod = BRW_CONDITIONAL_G;

      inst = emit(fs_inst(BRW_OPCODE_SEL, this->result, op[0], op[1]));
      inst->predicated = true;
      break;

   case ir_binop_pow:
      inst = emit(fs_inst(FS_OPCODE_POW, this->result, op[0], op[1]));
      break;

   case ir_unop_bit_not:
   case ir_unop_u2f:
   case ir_binop_lshift:
   case ir_binop_rshift:
   case ir_binop_bit_and:
   case ir_binop_bit_xor:
   case ir_binop_bit_or:
      assert(!"GLSL 1.30 features unsupported");
      break;
   }
}

void
fs_visitor::visit(ir_assignment *ir)
{
   struct fs_reg l, r;
   int i;
   int write_mask;
   fs_inst *inst;

   /* FINISHME: arrays on the lhs */
   ir->lhs->accept(this);
   l = this->result;

   ir->rhs->accept(this);
   r = this->result;

   /* FINISHME: This should really set to the correct maximal writemask for each
    * FINISHME: component written (in the loops below).  This case can only
    * FINISHME: occur for matrices, arrays, and structures.
    */
   if (ir->write_mask == 0) {
      assert(!ir->lhs->type->is_scalar() && !ir->lhs->type->is_vector());
      write_mask = WRITEMASK_XYZW;
   } else {
      assert(ir->lhs->type->is_vector() || ir->lhs->type->is_scalar());
      write_mask = ir->write_mask;
   }

   assert(l.file != BAD_FILE);
   assert(r.file != BAD_FILE);

   if (ir->condition) {
      /* Get the condition bool into the predicate. */
      ir->condition->accept(this);
      inst = emit(fs_inst(BRW_OPCODE_CMP, this->result, fs_reg(0)));
      inst->conditional_mod = BRW_CONDITIONAL_NZ;
   }

   for (i = 0; i < type_size(ir->lhs->type); i++) {
      if (i >= 4 || (write_mask & (1 << i))) {
         inst = emit(fs_inst(BRW_OPCODE_MOV, l, r));
         if (ir->condition)
            inst->predicated = true;
      }
      l.reg_offset++;
      r.reg_offset++;
   }
}

void
fs_visitor::visit(ir_texture *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_swizzle *ir)
{
   ir->val->accept(this);
   fs_reg val = this->result;

   fs_reg result = fs_reg(this, ir->type);
   this->result = result;

   for (unsigned int i = 0; i < ir->type->vector_elements; i++) {
      fs_reg channel = val;
      int swiz = 0;

      switch (i) {
      case 0:
         swiz = ir->mask.x;
         break;
      case 1:
         swiz = ir->mask.y;
         break;
      case 2:
         swiz = ir->mask.z;
         break;
      case 3:
         swiz = ir->mask.w;
         break;
      }

      channel.reg_offset += swiz;
      emit(fs_inst(BRW_OPCODE_MOV, result, channel));
      result.reg_offset++;
   }
}

void
fs_visitor::visit(ir_discard *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_constant *ir)
{
   fs_reg reg(this, ir->type);
   this->result = reg;

   for (unsigned int i = 0; i < ir->type->vector_elements; i++) {
      switch (ir->type->base_type) {
      case GLSL_TYPE_FLOAT:
         emit(fs_inst(BRW_OPCODE_MOV, reg, fs_reg(ir->value.f[i])));
         break;
      case GLSL_TYPE_UINT:
         emit(fs_inst(BRW_OPCODE_MOV, reg, fs_reg(ir->value.u[i])));
         break;
      case GLSL_TYPE_INT:
         emit(fs_inst(BRW_OPCODE_MOV, reg, fs_reg(ir->value.i[i])));
         break;
      case GLSL_TYPE_BOOL:
         emit(fs_inst(BRW_OPCODE_MOV, reg, fs_reg((int)ir->value.b[i])));
         break;
      default:
         assert(!"Non-float/uint/int/bool constant");
      }
      reg.reg_offset++;
   }
}

void
fs_visitor::visit(ir_if *ir)
{
   fs_inst *inst;

   /* Don't point the annotation at the if statement, because then it plus
    * the then and else blocks get printed.
    */
   this->base_ir = ir->condition;

   /* Generate the condition into the condition code. */
   ir->condition->accept(this);
   inst = emit(fs_inst(BRW_OPCODE_MOV, fs_reg(brw_null_reg()), this->result));
   inst->conditional_mod = BRW_CONDITIONAL_NZ;

   inst = emit(fs_inst(BRW_OPCODE_IF));
   inst->predicated = true;

   foreach_iter(exec_list_iterator, iter, ir->then_instructions) {
      ir_instruction *ir = (ir_instruction *)iter.get();
      this->base_ir = ir;

      ir->accept(this);
   }

   if (!ir->else_instructions.is_empty()) {
      emit(fs_inst(BRW_OPCODE_ELSE));

      foreach_iter(exec_list_iterator, iter, ir->else_instructions) {
         ir_instruction *ir = (ir_instruction *)iter.get();
         this->base_ir = ir;

         ir->accept(this);
      }
   }

   emit(fs_inst(BRW_OPCODE_ENDIF));
}

void
fs_visitor::visit(ir_loop *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_loop_jump *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_call *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_return *ir)
{
   assert(!"FINISHME");
}

void
fs_visitor::visit(ir_function *ir)
{
   /* Ignore function bodies other than main() -- we shouldn't see calls to
    * them since they should all be inlined before we get to ir_to_mesa.
    */
   if (strcmp(ir->name, "main") == 0) {
      const ir_function_signature *sig;
      exec_list empty;

      sig = ir->matching_signature(&empty);

      assert(sig);

      foreach_iter(exec_list_iterator, iter, sig->body) {
         ir_instruction *ir = (ir_instruction *)iter.get();
         this->base_ir = ir;

         ir->accept(this);
      }
   }
}

void
fs_visitor::visit(ir_function_signature *ir)
{
   assert(!"not reached");
   (void)ir;
}

fs_inst *
fs_visitor::emit(fs_inst inst)
{
   fs_inst *list_inst = new(mem_ctx) fs_inst;
   *list_inst = inst;

   list_inst->annotation = this->current_annotation;
   list_inst->ir = this->base_ir;

   this->instructions.push_tail(list_inst);

   return list_inst;
}

/** Emits a dummy fragment shader consisting of magenta for bringup purposes. */
void
fs_visitor::emit_dummy_fs()
{
   /* Everyone's favorite color. */
   emit(fs_inst(BRW_OPCODE_MOV,
                fs_reg(MRF, 2),
                fs_reg(1.0f)));
   emit(fs_inst(BRW_OPCODE_MOV,
                fs_reg(MRF, 3),
                fs_reg(0.0f)));
   emit(fs_inst(BRW_OPCODE_MOV,
                fs_reg(MRF, 4),
                fs_reg(1.0f)));
   emit(fs_inst(BRW_OPCODE_MOV,
                fs_reg(MRF, 5),
                fs_reg(0.0f)));

   fs_inst *write;
   write = emit(fs_inst(FS_OPCODE_FB_WRITE,
                        fs_reg(0),
                        fs_reg(0)));
}

/* The register location here is relative to the start of the URB
 * data.  It will get adjusted to be a real location before
 * generate_code() time.
 */
struct brw_reg
fs_visitor::interp_reg(int location, int channel)
{
   int regnr = location * 2 + channel / 2;
   int stride = (channel & 1) * 4;

   return brw_vec1_grf(regnr, stride);
}

/** Emits the interpolation for the varying inputs. */
void
fs_visitor::emit_interpolation()
{
   struct brw_reg g1_uw = retype(brw_vec1_grf(1, 0), BRW_REGISTER_TYPE_UW);
   /* For now, the source regs for the setup URB data will be unset,
    * since we don't know until codegen how many push constants we'll
    * use, and therefore what the setup URB offset is.
    */
   fs_reg src_reg = reg_undef;

   this->current_annotation = "compute pixel centers";
   this->pixel_x = fs_reg(this, glsl_type::uint_type);
   this->pixel_y = fs_reg(this, glsl_type::uint_type);
   emit(fs_inst(BRW_OPCODE_ADD,
                this->pixel_x,
                fs_reg(stride(suboffset(g1_uw, 4), 2, 4, 0)),
                fs_reg(brw_imm_v(0x10101010))));
   emit(fs_inst(BRW_OPCODE_ADD,
                this->pixel_y,
                fs_reg(stride(suboffset(g1_uw, 5), 2, 4, 0)),
                fs_reg(brw_imm_v(0x11001100))));

   this->current_annotation = "compute pixel deltas from v0";
   this->delta_x = fs_reg(this, glsl_type::float_type);
   this->delta_y = fs_reg(this, glsl_type::float_type);
   emit(fs_inst(BRW_OPCODE_ADD,
                this->delta_x,
                this->pixel_x,
                fs_reg(negate(brw_vec1_grf(1, 0)))));
   emit(fs_inst(BRW_OPCODE_ADD,
                this->delta_y,
                this->pixel_y,
                fs_reg(brw_vec1_grf(1, 1))));

   this->current_annotation = "compute pos.w and 1/pos.w";
   /* Compute wpos.  Unlike many other varying inputs, we usually need it
    * to produce 1/w, and the varying variable wouldn't show up.
    */
   fs_reg wpos = fs_reg(this, glsl_type::vec4_type);
   this->interp_attrs[FRAG_ATTRIB_WPOS] = wpos;
   emit(fs_inst(BRW_OPCODE_MOV, wpos, this->pixel_x)); /* FINISHME: ARB_fcc */
   wpos.reg_offset++;
   emit(fs_inst(BRW_OPCODE_MOV, wpos, this->pixel_y)); /* FINISHME: ARB_fcc */
   wpos.reg_offset++;
   emit(fs_inst(FS_OPCODE_LINTERP, wpos, this->delta_x, this->delta_y,
                interp_reg(FRAG_ATTRIB_WPOS, 2)));
   wpos.reg_offset++;
   emit(fs_inst(FS_OPCODE_LINTERP, wpos, this->delta_x, this->delta_y,
                interp_reg(FRAG_ATTRIB_WPOS, 3)));
   /* Compute the pixel W value from wpos.w. */
   this->pixel_w = fs_reg(this, glsl_type::float_type);
   emit(fs_inst(FS_OPCODE_RCP, this->pixel_w, wpos));

   /* FINISHME: gl_FrontFacing */

   foreach_iter(exec_list_iterator, iter, *this->shader->ir) {
      ir_instruction *ir = (ir_instruction *)iter.get();
      ir_variable *var = ir->as_variable();

      if (!var)
         continue;

      if (var->mode != ir_var_in)
         continue;

      /* If it's already set up (WPOS), skip. */
      if (var->location == 0)
         continue;

      this->current_annotation = talloc_asprintf(this->mem_ctx,
                                                 "interpolate %s "
                                                 "(FRAG_ATTRIB[%d])",
                                                 var->name,
                                                 var->location);
      emit_pinterp(var->location);
   }
   this->current_annotation = NULL;
}

void
fs_visitor::emit_pinterp(int location)
{
   fs_reg interp_attr = fs_reg(this, glsl_type::vec4_type);
   this->interp_attrs[location] = interp_attr;

   for (unsigned int i = 0; i < 4; i++) {
      struct brw_reg interp = interp_reg(location, i);
      emit(fs_inst(FS_OPCODE_LINTERP,
                   interp_attr,
                   this->delta_x,
                   this->delta_y,
                   fs_reg(interp)));
      interp_attr.reg_offset++;
   }
   interp_attr.reg_offset -= 4;

   for (unsigned int i = 0; i < 4; i++) {
      emit(fs_inst(BRW_OPCODE_MUL,
                   interp_attr,
                   interp_attr,
                   this->pixel_w));
      interp_attr.reg_offset++;
   }
}

void
fs_visitor::emit_fb_writes()
{
   this->current_annotation = "FB write";

   assert(this->frag_color || !"FINISHME: MRT");
   fs_reg color = *(variable_storage(this->frag_color));

   for (int i = 0; i < 4; i++) {
      emit(fs_inst(BRW_OPCODE_MOV,
                   fs_reg(MRF, 2 + i),
                   color));
      color.reg_offset++;
   }

   emit(fs_inst(FS_OPCODE_FB_WRITE,
                fs_reg(0),
                fs_reg(0)));

   this->current_annotation = NULL;
}

void
fs_visitor::generate_fb_write(fs_inst *inst)
{
   GLboolean eot = 1; /* FINISHME: MRT */
   /* FINISHME: AADS */

   /* Header is 2 regs, g0 and g1 are the contents. g0 will be implied
    * move, here's g1.
    */
   brw_push_insn_state(p);
   brw_set_mask_control(p, BRW_MASK_DISABLE);
   brw_set_compression_control(p, BRW_COMPRESSION_NONE);
   brw_MOV(p,
           brw_message_reg(1),
           brw_vec8_grf(1, 0));
   brw_pop_insn_state(p);

   int nr = 2 + 4;

   brw_fb_WRITE(p,
                8, /* dispatch_width */
                retype(vec8(brw_null_reg()), BRW_REGISTER_TYPE_UW),
                0, /* base MRF */
                retype(brw_vec8_grf(0, 0), BRW_REGISTER_TYPE_UW),
                0, /* FINISHME: MRT target */
                nr,
                0,
                eot);
}

void
fs_visitor::generate_linterp(fs_inst *inst,
                             struct brw_reg dst, struct brw_reg *src)
{
   struct brw_reg delta_x = src[0];
   struct brw_reg delta_y = src[1];
   struct brw_reg interp = src[2];

   if (brw->has_pln &&
       delta_y.nr == delta_x.nr + 1 &&
       (intel->gen >= 6 || (delta_x.nr & 1) == 0)) {
      brw_PLN(p, dst, interp, delta_x);
   } else {
      brw_LINE(p, brw_null_reg(), interp, delta_x);
      brw_MAC(p, dst, suboffset(interp, 1), delta_y);
   }
}

void
fs_visitor::generate_math(fs_inst *inst,
                          struct brw_reg dst, struct brw_reg *src)
{
   int op;

   switch (inst->opcode) {
   case FS_OPCODE_RCP:
      op = BRW_MATH_FUNCTION_INV;
      break;
   case FS_OPCODE_RSQ:
      op = BRW_MATH_FUNCTION_RSQ;
      break;
   case FS_OPCODE_SQRT:
      op = BRW_MATH_FUNCTION_SQRT;
      break;
   case FS_OPCODE_EXP2:
      op = BRW_MATH_FUNCTION_EXP;
      break;
   case FS_OPCODE_LOG2:
      op = BRW_MATH_FUNCTION_LOG;
      break;
   case FS_OPCODE_POW:
      op = BRW_MATH_FUNCTION_POW;
      break;
   case FS_OPCODE_SIN:
      op = BRW_MATH_FUNCTION_SIN;
      break;
   case FS_OPCODE_COS:
      op = BRW_MATH_FUNCTION_COS;
      break;
   default:
      assert(!"not reached: unknown math function");
      op = 0;
      break;
   }

   if (inst->opcode == FS_OPCODE_POW) {
      brw_MOV(p, brw_message_reg(3), src[1]);
   }

   brw_math(p, dst,
            op,
            inst->saturate ? BRW_MATH_SATURATE_SATURATE :
            BRW_MATH_SATURATE_NONE,
            2, src[0],
            BRW_MATH_DATA_VECTOR,
            BRW_MATH_PRECISION_FULL);
}

static void
trivial_assign_reg(int header_size, fs_reg *reg)
{
   if (reg->file == GRF && reg->reg != 0) {
      reg->hw_reg = header_size + reg->reg - 1 + reg->reg_offset;
      reg->reg = 0;
   }
}

void
fs_visitor::assign_curb_setup()
{
   c->prog_data.first_curbe_grf = c->key.nr_payload_regs;
   c->prog_data.curb_read_length = ALIGN(c->prog_data.nr_params, 8) / 8;

   /* Map the offsets in the UNIFORM file to fixed HW regs. */
   foreach_iter(exec_list_iterator, iter, this->instructions) {
      fs_inst *inst = (fs_inst *)iter.get();

      for (unsigned int i = 0; i < 3; i++) {
         if (inst->src[i].file == UNIFORM) {
            int constant_nr = inst->src[i].hw_reg + inst->src[i].reg_offset;
            struct brw_reg brw_reg;

            brw_reg = brw_vec1_grf(c->prog_data.first_curbe_grf +
                                   constant_nr / 8,
                                   constant_nr % 8);
            inst->src[i] = fs_reg(brw_reg);
         }
      }
   }
}

void
fs_visitor::assign_urb_setup()
{
   int urb_start = c->prog_data.first_curbe_grf + c->prog_data.curb_read_length;
   int interp_reg_nr[FRAG_ATTRIB_MAX];

   c->prog_data.urb_read_length = 0;

   /* Figure out where each of the incoming setup attributes lands. */
   for (unsigned int i = 0; i < FRAG_ATTRIB_MAX; i++) {
      interp_reg_nr[i] = -1;

      if (i != FRAG_ATTRIB_WPOS &&
          !(brw->fragment_program->Base.InputsRead & BITFIELD64_BIT(i)))
         continue;

      /* Each attribute is 4 setup channels, each of which is half a reg. */
      interp_reg_nr[i] = urb_start + c->prog_data.urb_read_length;
      c->prog_data.urb_read_length += 2;
   }

   /* Map the register numbers for FS_OPCODE_LINTERP so that it uses
    * the correct setup input.
    */
   foreach_iter(exec_list_iterator, iter, this->instructions) {
      fs_inst *inst = (fs_inst *)iter.get();

      if (inst->opcode != FS_OPCODE_LINTERP)
         continue;

      assert(inst->src[2].file == FIXED_HW_REG);

      int location = inst->src[2].fixed_hw_reg.nr / 2;
      assert(interp_reg_nr[location] != -1);
      inst->src[2].fixed_hw_reg.nr = (interp_reg_nr[location] +
                                      (inst->src[2].fixed_hw_reg.nr & 1));
   }

   this->first_non_payload_grf = urb_start + c->prog_data.urb_read_length;
}

void
fs_visitor::assign_regs()
{
   int header_size = this->first_non_payload_grf;
   int last_grf = 0;

   /* FINISHME: trivial assignment of register numbers */
   foreach_iter(exec_list_iterator, iter, this->instructions) {
      fs_inst *inst = (fs_inst *)iter.get();

      trivial_assign_reg(header_size, &inst->dst);
      trivial_assign_reg(header_size, &inst->src[0]);
      trivial_assign_reg(header_size, &inst->src[1]);

      last_grf = MAX2(last_grf, inst->dst.hw_reg);
      last_grf = MAX2(last_grf, inst->src[0].hw_reg);
      last_grf = MAX2(last_grf, inst->src[1].hw_reg);
   }

   this->grf_used = last_grf + 1;
}

static struct brw_reg brw_reg_from_fs_reg(fs_reg *reg)
{
   struct brw_reg brw_reg;

   switch (reg->file) {
   case GRF:
   case ARF:
   case MRF:
      brw_reg = brw_vec8_reg(reg->file,
                            reg->hw_reg, 0);
      brw_reg = retype(brw_reg, reg->type);
      break;
   case IMM:
      switch (reg->type) {
      case BRW_REGISTER_TYPE_F:
         brw_reg = brw_imm_f(reg->imm.f);
         break;
      case BRW_REGISTER_TYPE_D:
         brw_reg = brw_imm_f(reg->imm.i);
         break;
      case BRW_REGISTER_TYPE_UD:
         brw_reg = brw_imm_f(reg->imm.u);
         break;
      default:
         assert(!"not reached");
         break;
      }
      break;
   case FIXED_HW_REG:
      brw_reg = reg->fixed_hw_reg;
      break;
   case BAD_FILE:
      /* Probably unused. */
      brw_reg = brw_null_reg();
      break;
   case UNIFORM:
      assert(!"not reached");
      brw_reg = brw_null_reg();
      break;
   }
   if (reg->abs)
      brw_reg = brw_abs(brw_reg);
   if (reg->negate)
      brw_reg = negate(brw_reg);

   return brw_reg;
}

void
fs_visitor::generate_code()
{
   unsigned int annotation_len = 0;
   int last_native_inst = 0;
   struct brw_instruction *if_stack[16];
   int if_stack_depth = 0;

   memset(&if_stack, 0, sizeof(if_stack));
   foreach_iter(exec_list_iterator, iter, this->instructions) {
      fs_inst *inst = (fs_inst *)iter.get();
      struct brw_reg src[3], dst;

      for (unsigned int i = 0; i < 3; i++) {
         src[i] = brw_reg_from_fs_reg(&inst->src[i]);
      }
      dst = brw_reg_from_fs_reg(&inst->dst);

      brw_set_conditionalmod(p, inst->conditional_mod);
      brw_set_predicate_control(p, inst->predicated);

      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_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_CMP:
         brw_CMP(p, dst, inst->conditional_mod, src[0], src[1]);
         break;
      case BRW_OPCODE_IF:
         assert(if_stack_depth < 16);
         if_stack[if_stack_depth] = brw_IF(p, BRW_EXECUTE_8);
         if_stack_depth++;
         break;
      case BRW_OPCODE_ELSE:
         if_stack[if_stack_depth - 1] =
            brw_ELSE(p, if_stack[if_stack_depth - 1]);
         break;
      case BRW_OPCODE_ENDIF:
         if_stack_depth--;
         brw_ENDIF(p , if_stack[if_stack_depth]);
         break;
      case FS_OPCODE_RCP:
      case FS_OPCODE_RSQ:
      case FS_OPCODE_SQRT:
      case FS_OPCODE_EXP2:
      case FS_OPCODE_LOG2:
      case FS_OPCODE_POW:
      case FS_OPCODE_SIN:
      case FS_OPCODE_COS:
         generate_math(inst, dst, src);
         break;
      case FS_OPCODE_LINTERP:
         generate_linterp(inst, dst, src);
         break;
      case FS_OPCODE_FB_WRITE:
         generate_fb_write(inst);
         break;
      default:
         if (inst->opcode < (int)ARRAY_SIZE(brw_opcodes)) {
            _mesa_problem(ctx, "Unsupported opcode `%s' in FS",
                          brw_opcodes[inst->opcode].name);
         } else {
            _mesa_problem(ctx, "Unsupported opcode %d in FS", inst->opcode);
         }
         this->fail = true;
      }

      if (annotation_len < p->nr_insn) {
         annotation_len *= 2;
         if (annotation_len < 16)
            annotation_len = 16;

         this->annotation_string = talloc_realloc(this->mem_ctx,
                                                  annotation_string,
                                                  const char *,
                                                  annotation_len);
         this->annotation_ir = talloc_realloc(this->mem_ctx,
                                              annotation_ir,
                                              ir_instruction *,
                                              annotation_len);
      }

      for (unsigned int i = last_native_inst; i < p->nr_insn; i++) {
         this->annotation_string[i] = inst->annotation;
         this->annotation_ir[i] = inst->ir;
      }
      last_native_inst = p->nr_insn;
   }
}

GLboolean
brw_wm_fs_emit(struct brw_context *brw, struct brw_wm_compile *c)
{
   struct brw_compile *p = &c->func;
   struct intel_context *intel = &brw->intel;
   GLcontext *ctx = &intel->ctx;
   struct brw_shader *shader = NULL;
   struct gl_shader_program *prog = ctx->Shader.CurrentProgram;

   if (!prog)
      return GL_FALSE;

   if (!using_new_fs)
      return GL_FALSE;

   for (unsigned int i = 0; i < prog->_NumLinkedShaders; i++) {
      if (prog->_LinkedShaders[i]->Type == GL_FRAGMENT_SHADER) {
         shader = (struct brw_shader *)prog->_LinkedShaders[i];
         break;
      }
   }
   if (!shader)
      return GL_FALSE;

   /* We always use 8-wide mode, at least for now.  For one, flow
    * control only works in 8-wide.  Also, when we're fragment shader
    * bound, we're almost always under register pressure as well, so
    * 8-wide would save us from the performance cliff of spilling
    * regs.
    */
   c->dispatch_width = 8;

   if (INTEL_DEBUG & DEBUG_WM) {
      printf("GLSL IR for native fragment shader %d:\n", prog->Name);
      _mesa_print_ir(shader->ir, NULL);
      printf("\n");
   }

   /* Now the main event: Visit the shader IR and generate our FS IR for it.
    */
   fs_visitor v(c, shader);

   if (0) {
      v.emit_dummy_fs();
   } else {
      v.emit_interpolation();

      /* Generate FS IR for main().  (the visitor only descends into
       * functions called "main").
       */
      foreach_iter(exec_list_iterator, iter, *shader->ir) {
         ir_instruction *ir = (ir_instruction *)iter.get();
         v.base_ir = ir;
         ir->accept(&v);
      }

      if (v.fail)
         return GL_FALSE;

      v.emit_fb_writes();
      v.assign_curb_setup();
      v.assign_urb_setup();
      v.assign_regs();
   }

   v.generate_code();

   if (INTEL_DEBUG & DEBUG_WM) {
      const char *last_annotation_string = NULL;
      ir_instruction *last_annotation_ir = NULL;

      printf("Native code for fragment shader %d:\n", prog->Name);
      for (unsigned int i = 0; i < p->nr_insn; i++) {
         if (last_annotation_ir != v.annotation_ir[i]) {
            last_annotation_ir = v.annotation_ir[i];
            if (last_annotation_ir) {
               printf("   ");
               last_annotation_ir->print();
               printf("\n");
            }
         }
         if (last_annotation_string != v.annotation_string[i]) {
            last_annotation_string = v.annotation_string[i];
            if (last_annotation_string)
               printf("   %s\n", last_annotation_string);
         }
         brw_disasm(stdout, &p->store[i], intel->gen);
      }
      printf("\n");
   }

   c->prog_data.total_grf = v.grf_used;
   c->prog_data.total_scratch = 0;

   return GL_TRUE;
}