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,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
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  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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  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 "ir.h"
  33 #include "ir_visitor.h"
  34 #include "ir_optimization.h"
  35 #include "glsl_types.h"
  36
  37 /**
  38  * Visitor class for replacing expressions with ir_constant values.
  39  */
  40
  41 class ir_vec_index_to_swizzle_visitor : public ir_hierarchical_visitor {
  42 public:
  43    ir_vec_index_to_swizzle_visitor()
  44    {
  45       progress = false;
  46    }
  47
  48    ir_rvalue *convert_vec_index_to_swizzle(ir_rvalue *val);
  49
  50    virtual ir_visitor_status visit_enter(ir_expression *);
  51    virtual ir_visitor_status visit_enter(ir_swizzle *);
  52    virtual ir_visitor_status visit_enter(ir_assignment *);
  53    virtual ir_visitor_status visit_enter(ir_return *);
  54    virtual ir_visitor_status visit_enter(ir_call *);
  55    virtual ir_visitor_status visit_enter(ir_if *);
  56
  57    bool progress;
  58 };
  59
  60 ir_rvalue *
  61 ir_vec_index_to_swizzle_visitor::convert_vec_index_to_swizzle(ir_rvalue *ir)
  62 {
  63    ir_dereference_array *deref = ir->as_dereference_array();
  64    ir_constant *ir_constant;
  65
  66    if (!deref)
  67       return ir;
  68
  69    if (deref->array->type->is_matrix() || deref->array->type->is_array())
  70       return ir;
  71
  72    assert(deref->array_index->type->base_type == GLSL_TYPE_INT);
  73    ir_constant = deref->array_index->constant_expression_value();
  74    if (!ir_constant)
  75       return ir;
  76
  77    this->progress = true;
  78    return new ir_swizzle(deref->array, ir_constant->value.i[0], 0, 0, 0, 1);
  79 }
  80
  81 ir_visitor_status
  82 ir_vec_index_to_swizzle_visitor::visit_enter(ir_expression *ir)
  83 {
  84    unsigned int i;
  85
  86    for (i = 0; i < ir->get_num_operands(); i++) {
  87       ir->operands[i] = convert_vec_index_to_swizzle(ir->operands[i]);
  88    }
  89
  90    return visit_continue;
  91 }
  92
  93 ir_visitor_status
  94 ir_vec_index_to_swizzle_visitor::visit_enter(ir_swizzle *ir)
  95 {
  96    /* Can't be hit from normal GLSL, since you can't swizzle a scalar (which
  97     * the result of indexing a vector is.  But maybe at some point we'll end up
  98     * using swizzling of scalars for vector construction.
  99     */
 100    ir->val = convert_vec_index_to_swizzle(ir->val);
 101
 102    return visit_continue;
 103 }
 104
 105 ir_visitor_status
 106 ir_vec_index_to_swizzle_visitor::visit_enter(ir_assignment *ir)
 107 {
 108    ir->lhs = convert_vec_index_to_swizzle(ir->lhs);
 109    ir->rhs = convert_vec_index_to_swizzle(ir->rhs);
 110
 111    return visit_continue;
 112 }
 113
 114 ir_visitor_status
 115 ir_vec_index_to_swizzle_visitor::visit_enter(ir_call *ir)
 116 {
 117    foreach_iter(exec_list_iterator, iter, *ir) {
 118       ir_rvalue *param = (ir_rvalue *)iter.get();
 119       ir_rvalue *new_param = convert_vec_index_to_swizzle(param);
 120
 121       if (new_param != param) {
 122          param->insert_before(new_param);
 123          param->remove();
 124       }
 125    }
 126
 127    return visit_continue;
 128 }
 129
 130 ir_visitor_status
 131 ir_vec_index_to_swizzle_visitor::visit_enter(ir_return *ir)
 132 {
 133    if (ir->value) {
 134       ir->value = convert_vec_index_to_swizzle(ir->value);
 135    }
 136
 137    return visit_continue;
 138 }
 139
 140 ir_visitor_status
 141 ir_vec_index_to_swizzle_visitor::visit_enter(ir_if *ir)
 142 {
 143    ir->condition = convert_vec_index_to_swizzle(ir->condition);
 144
 145    return visit_continue;
 146 }
 147
 148 bool
 149 do_vec_index_to_swizzle(exec_list *instructions)
 150 {
 151    ir_vec_index_to_swizzle_visitor v;
 152
 153    v.run(instructions);
 154
 155    return false;
 156 }