ir_vec_index_to_swizzle.cpp

   1 /*
   2  * Copyright © 2010 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"),
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   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,
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  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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  22  */
  23
  24 /**
  25  * \file ir_vec_index_to_swizzle.cpp
  26  *
  27  * Turns constant indexing into vector types to swizzles.  This will
  28  * let other swizzle-aware optimization passes catch these constructs,
  29  * and codegen backends not have to worry about this case.
  30  */
  31
  32 #include <stdio.h>
  33 #include "ir.h"
  34 #include "ir_visitor.h"
  35 #include "ir_optimization.h"
  36 #include "ir_print_visitor.h"
  37 #include "glsl_types.h"
  38
  39 /**
  40  * Visitor class for replacing expressions with ir_constant values.
  41  */
  42
  43 class ir_vec_index_to_swizzle_visitor : public ir_hierarchical_visitor {
  44 public:
  45    ir_vec_index_to_swizzle_visitor()
  46    {
  47       progress = false;
  48    }
  49
  50    ir_rvalue *convert_vec_index_to_swizzle(ir_rvalue *val);
  51
  52    virtual ir_visitor_status visit_enter(ir_expression *);
  53    virtual ir_visitor_status visit_enter(ir_swizzle *);
  54    virtual ir_visitor_status visit_enter(ir_assignment *);
  55    virtual ir_visitor_status visit_enter(ir_return *);
  56    virtual ir_visitor_status visit_enter(ir_call *);
  57    virtual ir_visitor_status visit_enter(ir_if *);
  58
  59    bool progress;
  60 };
  61
  62 ir_rvalue *
  63 ir_vec_index_to_swizzle_visitor::convert_vec_index_to_swizzle(ir_rvalue *ir)
  64 {
  65    ir_dereference_array *deref = ir->as_dereference_array();
  66    ir_constant *ir_constant;
  67
  68    if (!deref)
  69       return ir;
  70
  71    if (deref->array->type->is_matrix() || deref->array->type->is_array())
  72       return ir;
  73
  74    assert(deref->array_index->type->base_type == GLSL_TYPE_INT);
  75    ir_constant = deref->array_index->constant_expression_value();
  76    if (!ir_constant)
  77       return ir;
  78
  79    this->progress = true;
  80    return new ir_swizzle(deref->array, ir_constant->value.i[0], 0, 0, 0, 1);
  81 }
  82
  83 ir_visitor_status
  84 ir_vec_index_to_swizzle_visitor::visit_enter(ir_expression *ir)
  85 {
  86    unsigned int i;
  87
  88    for (i = 0; i < ir->get_num_operands(); i++) {
  89       ir->operands[i] = convert_vec_index_to_swizzle(ir->operands[i]);
  90    }
  91
  92    return visit_continue;
  93 }
  94
  95 ir_visitor_status
  96 ir_vec_index_to_swizzle_visitor::visit_enter(ir_swizzle *ir)
  97 {
  98    /* Can't be hit from normal GLSL, since you can't swizzle a scalar (which
  99     * the result of indexing a vector is.  But maybe at some point we'll end up
 100     * using swizzling of scalars for vector construction.
 101     */
 102    ir->val = convert_vec_index_to_swizzle(ir->val);
 103
 104    return visit_continue;
 105 }
 106
 107 ir_visitor_status
 108 ir_vec_index_to_swizzle_visitor::visit_enter(ir_assignment *ir)
 109 {
 110    ir->lhs = convert_vec_index_to_swizzle(ir->lhs);
 111    ir->rhs = convert_vec_index_to_swizzle(ir->rhs);
 112
 113    return visit_continue;
 114 }
 115
 116 ir_visitor_status
 117 ir_vec_index_to_swizzle_visitor::visit_enter(ir_call *ir)
 118 {
 119    foreach_iter(exec_list_iterator, iter, *ir) {
 120       ir_rvalue *param = (ir_rvalue *)iter.get();
 121       ir_rvalue *new_param = convert_vec_index_to_swizzle(param);
 122
 123       if (new_param != param) {
 124          param->insert_before(new_param);
 125          param->remove();
 126       }
 127    }
 128
 129    return visit_continue;
 130 }
 131
 132 ir_visitor_status
 133 ir_vec_index_to_swizzle_visitor::visit_enter(ir_return *ir)
 134 {
 135    if (ir->value) {
 136       ir->value = convert_vec_index_to_swizzle(ir->value);
 137    }
 138
 139    return visit_continue;
 140 }
 141
 142 ir_visitor_status
 143 ir_vec_index_to_swizzle_visitor::visit_enter(ir_if *ir)
 144 {
 145    ir->condition = convert_vec_index_to_swizzle(ir->condition);
 146
 147    return visit_continue;
 148 }
 149
 150 bool
 151 do_vec_index_to_swizzle(exec_list *instructions)
 152 {
 153    ir_vec_index_to_swizzle_visitor v;
 154
 155    v.run(instructions);
 156
 157    return false;
 158 }