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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 namespace {
     36 
     37 class ir_swizzle_swizzle_visitor : public ir_hierarchical_visitor {
     38 public:
     39    ir_swizzle_swizzle_visitor()
     40    {
     41       progress = false;
     42    }
     43 
     44    virtual ir_visitor_status visit_enter(ir_swizzle *);
     45 
     46    bool progress;
     47 };
     48 
     49 } /* unnamed namespace */
     50 
     51 ir_visitor_status
     52 ir_swizzle_swizzle_visitor::visit_enter(ir_swizzle *ir)
     53 {
     54    int mask2[4];
     55 
     56    ir_swizzle *swiz2 = ir->val->as_swizzle();
     57    if (!swiz2)
     58       return visit_continue;
     59 
     60    memset(&mask2, 0, sizeof(mask2));
     61    if (swiz2->mask.num_components >= 1)
     62       mask2[0] = swiz2->mask.x;
     63    if (swiz2->mask.num_components >= 2)
     64       mask2[1] = swiz2->mask.y;
     65    if (swiz2->mask.num_components >= 3)
     66       mask2[2] = swiz2->mask.z;
     67    if (swiz2->mask.num_components >= 4)
     68       mask2[3] = swiz2->mask.w;
     69 
     70    if (ir->mask.num_components >= 1)
     71       ir->mask.x = mask2[ir->mask.x];
     72    if (ir->mask.num_components >= 2)
     73       ir->mask.y = mask2[ir->mask.y];
     74    if (ir->mask.num_components >= 3)
     75       ir->mask.z = mask2[ir->mask.z];
     76    if (ir->mask.num_components >= 4)
     77       ir->mask.w = mask2[ir->mask.w];
     78 
     79    ir->val = swiz2->val;
     80 
     81    this->progress = true;
     82 
     83    return visit_continue;
     84 }
     85 
     86 /**
     87  * Does a copy propagation pass on the code present in the instruction stream.
     88  */
     89 bool
     90 do_swizzle_swizzle(exec_list *instructions)
     91 {
     92    ir_swizzle_swizzle_visitor v;
     93 
     94    v.run(instructions);
     95 
     96    return v.progress;
     97 }
     98