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      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 = expr->operands[2]->constant_expression_value();
     69    if (idx != NULL) {
     70       /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
     71        * a new temporary.  The new temporary gets assigned as
     72        *
     73        *     t = vec
     74        *     t.mask = scalar
     75        *
     76        * where mask is the component selected by index.
     77        */
     78       ir_variable *const temp =
     79          factory.make_temp(expr->operands[0]->type, "vec_tmp");
     80 
     81       const int mask = 1 << idx->value.i[0];
     82 
     83       factory.emit(assign(temp, expr->operands[0]));
     84       factory.emit(assign(temp, expr->operands[1], mask));
     85 
     86       this->progress = true;
     87       *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
     88    } else if (this->lower_nonconstant_index) {
     89       /* Replace (vector_insert (vec) (scalar) (index)) with a dereference of
     90        * a new temporary.  The new temporary gets assigned as
     91        *
     92        *     t = vec
     93        *     if (index == 0)
     94        *         t.x = scalar
     95        *     if (index == 1)
     96        *         t.y = scalar
     97        *     if (index == 2)
     98        *         t.z = scalar
     99        *     if (index == 3)
    100        *         t.w = scalar
    101        */
    102       ir_variable *const temp =
    103          factory.make_temp(expr->operands[0]->type, "vec_tmp");
    104 
    105       ir_variable *const src_temp =
    106          factory.make_temp(expr->operands[1]->type, "src_temp");
    107 
    108       factory.emit(assign(temp, expr->operands[0]));
    109       factory.emit(assign(src_temp, expr->operands[1]));
    110 
    111       assert(expr->operands[2]->type == glsl_type::int_type ||
    112              expr->operands[2]->type == glsl_type::uint_type);
    113 
    114       for (unsigned i = 0; i < expr->type->vector_elements; i++) {
    115          ir_constant *const cmp_index =
    116             ir_constant::zero(factory.mem_ctx, expr->operands[2]->type);
    117          cmp_index->value.u[0] = i;
    118 
    119          ir_variable *const cmp_result =
    120             factory.make_temp(glsl_type::bool_type, "index_condition");
    121 
    122          factory.emit(assign(cmp_result,
    123                              equal(expr->operands[2]->clone(factory.mem_ctx,
    124                                                             NULL),
    125                                    cmp_index)));
    126 
    127          factory.emit(if_tree(cmp_result,
    128                               assign(temp, src_temp, WRITEMASK_X << i)));
    129       }
    130 
    131       this->progress = true;
    132       *rv = new(factory.mem_ctx) ir_dereference_variable(temp);
    133    }
    134 
    135    base_ir->insert_before(factory.instructions);
    136 }
    137 
    138 bool
    139 lower_vector_insert(exec_list *instructions, bool lower_nonconstant_index)
    140 {
    141    vector_insert_visitor v(lower_nonconstant_index);
    142 
    143    visit_list_elements(&v, instructions);
    144 
    145    return v.progress;
    146 }
    147