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      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 ir_expression_flattening.cpp
     26  *
     27  * Takes the leaves of expression trees and makes them dereferences of
     28  * assignments of the leaves to temporaries, according to a predicate.
     29  *
     30  * This is used for breaking down matrix operations, where it's easier to
     31  * create a temporary and work on each of its vector components individually.
     32  */
     33 
     34 #include "ir.h"
     35 #include "ir_visitor.h"
     36 #include "ir_rvalue_visitor.h"
     37 #include "ir_expression_flattening.h"
     38 #include "glsl_types.h"
     39 
     40 class ir_expression_flattening_visitor : public ir_rvalue_visitor {
     41 public:
     42    ir_expression_flattening_visitor(bool (*predicate)(ir_instruction *ir))
     43    {
     44       this->predicate = predicate;
     45    }
     46 
     47    virtual ~ir_expression_flattening_visitor()
     48    {
     49       /* empty */
     50    }
     51 
     52    void handle_rvalue(ir_rvalue **rvalue);
     53    bool (*predicate)(ir_instruction *ir);
     54 };
     55 
     56 void
     57 do_expression_flattening(exec_list *instructions,
     58 			 bool (*predicate)(ir_instruction *ir))
     59 {
     60    ir_expression_flattening_visitor v(predicate);
     61 
     62    foreach_iter(exec_list_iterator, iter, *instructions) {
     63       ir_instruction *ir = (ir_instruction *)iter.get();
     64 
     65       ir->accept(&v);
     66    }
     67 }
     68 
     69 void
     70 ir_expression_flattening_visitor::handle_rvalue(ir_rvalue **rvalue)
     71 {
     72    ir_variable *var;
     73    ir_assignment *assign;
     74    ir_rvalue *ir = *rvalue;
     75 
     76    if (!ir || !this->predicate(ir))
     77       return;
     78 
     79    void *ctx = ralloc_parent(ir);
     80 
     81    var = new(ctx) ir_variable(ir->type, "flattening_tmp", ir_var_temporary);
     82    base_ir->insert_before(var);
     83 
     84    assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(var),
     85 				   ir,
     86 				   NULL);
     87    base_ir->insert_before(assign);
     88 
     89    *rvalue = new(ctx) ir_dereference_variable(var);
     90 }
     91