src/compiler/glsl/lower_vector_insert.cpp

   1 /*
   2  * Copyright © 2013 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23 #include "ir.h"
  24 #include "ir_builder.h"
  25 #include "ir_rvalue_visitor.h"
  26 #include "ir_optimization.h"
  27
  28 using namespace ir_builder;
  29
  30 namespace {
  31
  32 class vector_insert_visitor : public ir_rvalue_visitor {
  33 public:
  34    vector_insert_visitor(bool lower_nonconstant_index)
  35       : progress(false), lower_nonconstant_index(lower_nonconstant_index)
  36    {
  37       factory.instructions = &factory_instructions;
  38    }
  39
  40    virtual ~vector_insert_visitor()
  41    {
  42       assert(factory_instructions.is_empty());
  43    }
  44
  45    virtual void handle_rvalue(ir_rvalue **rv);
  46
  47    ir_factory factory;
  48    exec_list factory_instructions;
  49    bool progress;
  50    bool lower_nonconstant_index;
  51 };
  52
  53 } /* anonymous namespace */
  54
  55 void
  56 vector_insert_visitor::handle_rvalue(ir_rvalue **rv)
  57 {
  58    if (*rv == NULL || (*rv)->ir_type != ir_type_expression)
  59       return;
  60
  61    ir_expression *const expr = (ir_expression *) *rv;
  62
  63    if (likely(expr->operation != ir_triop_vector_insert))
  64       return;
  65
  66    factory.mem_ctx = ralloc_parent(expr);
  67
  68    ir_constant *const idx =
  69       expr->operands[2]->constant_expression_value(factory.mem_ctx);
  70    if (idx != NULL) {
  71       /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
  72        * a new temporary.  The new temporary gets assigned as
  73        *
  74        *     t = vec
  75        *     t.mask = scalar
  76        *
  77        * where mask is the component selected by index.
  78        */
  79       ir_variable *const temp =
  80          factory.make_temp(expr->operands[0]->type, "vec_tmp");
  81
  82       const int mask = 1 << idx->value.i[0];
  83
  84       factory.emit(assign(temp, expr->operands[0]));
  85       factory.emit(assign(temp, expr->operands[1], mask));
  86
  87       this->progress = true;
  88       *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
  89    } else if (this->lower_nonconstant_index) {
  90       /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
  91        * a new temporary.  The new temporary gets assigned as
  92        *
  93        *     t = vec
  94        *     if (index == 0)
  95        *         t.x = scalar
  96        *     if (index == 1)
  97        *         t.y = scalar
  98        *     if (index == 2)
  99        *         t.z = scalar
 100        *     if (index == 3)
 101        *         t.w = scalar
 102        */
 103       ir_variable *const temp =
 104          factory.make_temp(expr->operands[0]->type, "vec_tmp");
 105
 106       ir_variable *const src_temp =
 107          factory.make_temp(expr->operands[1]->type, "src_temp");
 108
 109       factory.emit(assign(temp, expr->operands[0]));
 110       factory.emit(assign(src_temp, expr->operands[1]));
 111
 112       assert(expr->operands[2]->type == glsl_type::int_type ||
 113              expr->operands[2]->type == glsl_type::uint_type);
 114
 115       for (unsigned i = 0; i < expr->type->vector_elements; i++) {
 116          ir_constant *const cmp_index =
 117             ir_constant::zero(factory.mem_ctx, expr->operands[2]->type);
 118          cmp_index->value.u[0] = i;
 119
 120          ir_variable *const cmp_result =
 121             factory.make_temp(glsl_type::bool_type, "index_condition");
 122
 123          factory.emit(assign(cmp_result,
 124                              equal(expr->operands[2]->clone(factory.mem_ctx,
 125                                                             NULL),
 126                                    cmp_index)));
 127
 128          factory.emit(if_tree(cmp_result,
 129                               assign(temp, src_temp, WRITEMASK_X << i)));
 130       }
 131
 132       this->progress = true;
 133       *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
 134    }
 135
 136    base_ir->insert_before(factory.instructions);
 137 }
 138
 139 bool
 140 lower_vector_insert(exec_list *instructions, bool lower_nonconstant_index)
 141 {
 142    vector_insert_visitor v(lower_nonconstant_index);
 143
 144    visit_list_elements(&v, instructions);
 145
 146    return v.progress;
 147 }