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"), 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 24 /** 25 * \file lower_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 #include "main/macros.h" 37 38 /** 39 * Visitor class for replacing expressions with ir_constant values. 40 */ 41 42 class ir_vec_index_to_swizzle_visitor : public ir_hierarchical_visitor { 43 public: 44 ir_vec_index_to_swizzle_visitor() 45 { 46 progress = false; 47 } 48 49 ir_rvalue *convert_vec_index_to_swizzle(ir_rvalue *val); 50 51 virtual ir_visitor_status visit_enter(ir_expression *); 52 virtual ir_visitor_status visit_enter(ir_swizzle *); 53 virtual ir_visitor_status visit_enter(ir_assignment *); 54 virtual ir_visitor_status visit_enter(ir_return *); 55 virtual ir_visitor_status visit_enter(ir_call *); 56 virtual ir_visitor_status visit_enter(ir_if *); 57 58 bool progress; 59 }; 60 61 ir_rvalue * 62 ir_vec_index_to_swizzle_visitor::convert_vec_index_to_swizzle(ir_rvalue *ir) 63 { 64 ir_dereference_array *deref = ir->as_dereference_array(); 65 ir_constant *ir_constant; 66 67 if (!deref) 68 return ir; 69 70 if (deref->array->type->is_matrix() || deref->array->type->is_array()) 71 return ir; 72 73 assert(deref->array_index->type->base_type == GLSL_TYPE_INT); 74 ir_constant = deref->array_index->constant_expression_value(); 75 if (!ir_constant) 76 return ir; 77 78 void *ctx = ralloc_parent(ir); 79 this->progress = true; 80 81 /* Page 40 of the GLSL 1.20 spec says: 82 * 83 * "When indexing with non-constant expressions, behavior is undefined 84 * if the index is negative, or greater than or equal to the size of 85 * the vector." 86 * 87 * The quoted spec text mentions non-constant expressions, but this code 88 * operates on constants. These constants are the result of non-constant 89 * expressions that have been optimized to constants. The common case here 90 * is a loop counter from an unrolled loop that is used to index a vector. 91 * 92 * The ir_swizzle constructor gets angry if the index is negative or too 93 * large. For simplicity sake, just clamp the index to [0, size-1]. 94 */ 95 const int i = MIN2(MAX2(ir_constant->value.i[0], 0), 96 (deref->array->type->vector_elements - 1)); 97 98 return new(ctx) ir_swizzle(deref->array, i, 0, 0, 0, 1); 99 } 100 101 ir_visitor_status 102 ir_vec_index_to_swizzle_visitor::visit_enter(ir_expression *ir) 103 { 104 unsigned int i; 105 106 for (i = 0; i < ir->get_num_operands(); i++) { 107 ir->operands[i] = convert_vec_index_to_swizzle(ir->operands[i]); 108 } 109 110 return visit_continue; 111 } 112 113 ir_visitor_status 114 ir_vec_index_to_swizzle_visitor::visit_enter(ir_swizzle *ir) 115 { 116 /* Can't be hit from normal GLSL, since you can't swizzle a scalar (which 117 * the result of indexing a vector is. But maybe at some point we'll end up 118 * using swizzling of scalars for vector construction. 119 */ 120 ir->val = convert_vec_index_to_swizzle(ir->val); 121 122 return visit_continue; 123 } 124 125 ir_visitor_status 126 ir_vec_index_to_swizzle_visitor::visit_enter(ir_assignment *ir) 127 { 128 ir->set_lhs(convert_vec_index_to_swizzle(ir->lhs)); 129 ir->rhs = convert_vec_index_to_swizzle(ir->rhs); 130 131 return visit_continue; 132 } 133 134 ir_visitor_status 135 ir_vec_index_to_swizzle_visitor::visit_enter(ir_call *ir) 136 { 137 foreach_iter(exec_list_iterator, iter, *ir) { 138 ir_rvalue *param = (ir_rvalue *)iter.get(); 139 ir_rvalue *new_param = convert_vec_index_to_swizzle(param); 140 141 if (new_param != param) { 142 param->replace_with(new_param); 143 } 144 } 145 146 return visit_continue; 147 } 148 149 ir_visitor_status 150 ir_vec_index_to_swizzle_visitor::visit_enter(ir_return *ir) 151 { 152 if (ir->value) { 153 ir->value = convert_vec_index_to_swizzle(ir->value); 154 } 155 156 return visit_continue; 157 } 158 159 ir_visitor_status 160 ir_vec_index_to_swizzle_visitor::visit_enter(ir_if *ir) 161 { 162 ir->condition = convert_vec_index_to_swizzle(ir->condition); 163 164 return visit_continue; 165 } 166 167 bool 168 do_vec_index_to_swizzle(exec_list *instructions) 169 { 170 ir_vec_index_to_swizzle_visitor v; 171 172 v.run(instructions); 173 174 return v.progress; 175 } 176
