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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 opt_swizzle_swizzle.cpp
     26  *
     27  * Eliminates the second swizzle in a swizzle chain.
     28  */
     29 
     30 #include "ir.h"
     31 #include "ir_visitor.h"
     32 #include "ir_optimization.h"
     33 #include "glsl_types.h"
     34 
     35 class ir_swizzle_swizzle_visitor : public ir_hierarchical_visitor {
     36 public:
     37    ir_swizzle_swizzle_visitor()
     38    {
     39       progress = false;
     40    }
     41 
     42    virtual ir_visitor_status visit_enter(ir_swizzle *);
     43 
     44    bool progress;
     45 };
     46 
     47 ir_visitor_status
     48 ir_swizzle_swizzle_visitor::visit_enter(ir_swizzle *ir)
     49 {
     50    int mask2[4];
     51 
     52    ir_swizzle *swiz2 = ir->val->as_swizzle();
     53    if (!swiz2)
     54       return visit_continue;
     55 
     56    memset(&mask2, 0, sizeof(mask2));
     57    if (swiz2->mask.num_components >= 1)
     58       mask2[0] = swiz2->mask.x;
     59    if (swiz2->mask.num_components >= 2)
     60       mask2[1] = swiz2->mask.y;
     61    if (swiz2->mask.num_components >= 3)
     62       mask2[2] = swiz2->mask.z;
     63    if (swiz2->mask.num_components >= 4)
     64       mask2[3] = swiz2->mask.w;
     65 
     66    if (ir->mask.num_components >= 1)
     67       ir->mask.x = mask2[ir->mask.x];
     68    if (ir->mask.num_components >= 2)
     69       ir->mask.y = mask2[ir->mask.y];
     70    if (ir->mask.num_components >= 3)
     71       ir->mask.z = mask2[ir->mask.z];
     72    if (ir->mask.num_components >= 4)
     73       ir->mask.w = mask2[ir->mask.w];
     74 
     75    ir->val = swiz2->val;
     76 
     77    this->progress = true;
     78 
     79    return visit_continue;
     80 }
     81 
     82 /**
     83  * Does a copy propagation pass on the code present in the instruction stream.
     84  */
     85 bool
     86 do_swizzle_swizzle(exec_list *instructions)
     87 {
     88    ir_swizzle_swizzle_visitor v;
     89 
     90    v.run(instructions);
     91 
     92    return v.progress;
     93 }
     94