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      1 /*
      2  * Copyright  2013 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 lower_offset_array.cpp
     26  *
     27  * IR lower pass to decompose ir_texture ir_tg4 with an array of offsets
     28  * into four ir_tg4s with a single ivec2 offset, select the .w component of each,
     29  * and return those four values packed into a gvec4.
     30  *
     31  * \author Chris Forbes <chrisf (at) ijw.co.nz>
     32  */
     33 
     34 #include "compiler/glsl_types.h"
     35 #include "ir.h"
     36 #include "ir_builder.h"
     37 #include "ir_optimization.h"
     38 #include "ir_rvalue_visitor.h"
     39 
     40 using namespace ir_builder;
     41 
     42 class lower_offset_array_visitor : public ir_rvalue_visitor {
     43 public:
     44    lower_offset_array_visitor()
     45    {
     46       progress = false;
     47    }
     48 
     49    void handle_rvalue(ir_rvalue **rv);
     50 
     51    bool progress;
     52 };
     53 
     54 void
     55 lower_offset_array_visitor::handle_rvalue(ir_rvalue **rv)
     56 {
     57    if (*rv == NULL || (*rv)->ir_type != ir_type_texture)
     58       return;
     59 
     60    ir_texture *ir = (ir_texture *) *rv;
     61    if (ir->op != ir_tg4 || !ir->offset || !ir->offset->type->is_array())
     62       return;
     63 
     64    void *mem_ctx = ralloc_parent(ir);
     65 
     66    ir_variable *var =
     67       new (mem_ctx) ir_variable(ir->type, "result", ir_var_temporary);
     68    base_ir->insert_before(var);
     69 
     70    for (int i = 0; i < 4; i++) {
     71       ir_texture *tex = ir->clone(mem_ctx, NULL);
     72       tex->offset = new (mem_ctx) ir_dereference_array(tex->offset,
     73             new (mem_ctx) ir_constant(i));
     74 
     75       base_ir->insert_before(assign(var, swizzle_w(tex), 1 << i));
     76    }
     77 
     78    *rv = new (mem_ctx) ir_dereference_variable(var);
     79 
     80    progress = true;
     81 }
     82 
     83 bool
     84 lower_offset_arrays(exec_list *instructions)
     85 {
     86    lower_offset_array_visitor v;
     87 
     88    visit_list_elements(&v, instructions);
     89 
     90    return v.progress;
     91 }
     92