workbench/libs/mesa/src/glsl/opt_noop_swizzle.cpp

   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_noop_swizzle.cpp
  26  *
  27  * If a swizzle doesn't change the order or count of components, then
  28  * remove the swizzle so that other optimization passes see the value
  29  * behind it.
  30  */
  31
  32 #include "ir.h"
  33 #include "ir_visitor.h"
  34 #include "ir_rvalue_visitor.h"
  35 #include "ir_print_visitor.h"
  36 #include "glsl_types.h"
  37
  38 class ir_noop_swizzle_visitor : public ir_rvalue_visitor {
  39 public:
  40    ir_noop_swizzle_visitor()
  41    {
  42       this->progress = false;
  43    }
  44
  45    void handle_rvalue(ir_rvalue **rvalue);
  46    bool progress;
  47 };
  48
  49 void
  50 ir_noop_swizzle_visitor::handle_rvalue(ir_rvalue **rvalue)
  51 {
  52    if (!*rvalue)
  53       return;
  54
  55    ir_swizzle *swiz = (*rvalue)->as_swizzle();
  56    if (!swiz || swiz->type != swiz->val->type)
  57       return;
  58
  59    int elems = swiz->val->type->vector_elements;
  60    if (swiz->mask.x != 0)
  61       return;
  62    if (elems >= 2 && swiz->mask.y != 1)
  63       return;
  64    if (elems >= 3 && swiz->mask.z != 2)
  65       return;
  66    if (elems >= 4 && swiz->mask.w != 3)
  67       return;
  68
  69    this->progress = true;
  70    *rvalue = swiz->val;
  71 }
  72
  73 bool
  74 do_noop_swizzle(exec_list *instructions)
  75 {
  76    ir_noop_swizzle_visitor v;
  77    visit_list_elements(&v, instructions);
  78
  79    return v.progress;
  80 }