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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_deref_visitor : public ir_rvalue_enter_visitor {
     33 public:
     34    vector_deref_visitor()
     35       : progress(false)
     36    {
     37    }
     38 
     39    virtual ~vector_deref_visitor()
     40    {
     41    }
     42 
     43    virtual void handle_rvalue(ir_rvalue **rv);
     44    virtual ir_visitor_status visit_enter(ir_assignment *ir);
     45 
     46    bool progress;
     47 };
     48 
     49 } /* anonymous namespace */
     50 
     51 ir_visitor_status
     52 vector_deref_visitor::visit_enter(ir_assignment *ir)
     53 {
     54    if (!ir->lhs || ir->lhs->ir_type != ir_type_dereference_array)
     55       return ir_rvalue_enter_visitor::visit_enter(ir);
     56 
     57    ir_dereference_array *const deref = (ir_dereference_array *) ir->lhs;
     58    if (!deref->array->type->is_vector())
     59       return ir_rvalue_enter_visitor::visit_enter(ir);
     60 
     61    ir_dereference *const new_lhs = (ir_dereference *) deref->array;
     62    ir->set_lhs(new_lhs);
     63 
     64    ir_constant *old_index_constant = deref->array_index->constant_expression_value();
     65    void *mem_ctx = ralloc_parent(ir);
     66    if (!old_index_constant) {
     67       ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
     68                                            new_lhs->type,
     69                                            new_lhs->clone(mem_ctx, NULL),
     70                                            ir->rhs,
     71                                            deref->array_index);
     72       ir->write_mask = (1 << new_lhs->type->vector_elements) - 1;
     73    } else {
     74       ir->write_mask = 1 << old_index_constant->get_int_component(0);
     75    }
     76 
     77    return ir_rvalue_enter_visitor::visit_enter(ir);
     78 }
     79 
     80 void
     81 vector_deref_visitor::handle_rvalue(ir_rvalue **rv)
     82 {
     83    if (*rv == NULL || (*rv)->ir_type != ir_type_dereference_array)
     84       return;
     85 
     86    ir_dereference_array *const deref = (ir_dereference_array *) *rv;
     87    if (!deref->array->type->is_vector())
     88       return;
     89 
     90    void *mem_ctx = ralloc_parent(deref);
     91    *rv = new(mem_ctx) ir_expression(ir_binop_vector_extract,
     92                                     deref->array,
     93                                     deref->array_index);
     94 }
     95 
     96 bool
     97 lower_vector_derefs(gl_linked_shader *shader)
     98 {
     99    vector_deref_visitor v;
    100 
    101    visit_list_elements(&v, shader->ir);
    102 
    103    return v.progress;
    104 }
    105