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 "compiler/glsl_types.h"
  36
  37 namespace {
  38
  39 class ir_noop_swizzle_visitor : public ir_rvalue_visitor {
  40 public:
  41    ir_noop_swizzle_visitor()
  42    {
  43       this->progress = false;
  44    }
  45
  46    void handle_rvalue(ir_rvalue **rvalue);
  47    bool progress;
  48 };
  49
  50 } /* unnamed namespace */
  51
  52 void
  53 ir_noop_swizzle_visitor::handle_rvalue(ir_rvalue **rvalue)
  54 {
  55    if (!*rvalue)
  56       return;
  57
  58    ir_swizzle *swiz = (*rvalue)->as_swizzle();
  59    if (!swiz || swiz->type != swiz->val->type)
  60       return;
  61
  62    int elems = swiz->val->type->vector_elements;
  63    if (swiz->mask.x != 0)
  64       return;
  65    if (elems >= 2 && swiz->mask.y != 1)
  66       return;
  67    if (elems >= 3 && swiz->mask.z != 2)
  68       return;
  69    if (elems >= 4 && swiz->mask.w != 3)
  70       return;
  71
  72    this->progress = true;
  73    *rvalue = swiz->val;
  74 }
  75
  76 bool
  77 do_noop_swizzle(exec_list *instructions)
  78 {
  79    ir_noop_swizzle_visitor v;
  80    visit_list_elements(&v, instructions);
  81
  82    return v.progress;
  83 }