src/compiler/glsl/lower_vector_derefs.cpp

   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 #include "ir.h"
  24 #include "ir_builder.h"
  25 #include "ir_rvalue_visitor.h"
  26 #include "ir_optimization.h"
  27 #include "main/mtypes.h"
  28
  29 using namespace ir_builder;
  30
  31 namespace {
  32
  33 class vector_deref_visitor : public ir_rvalue_enter_visitor {
  34 public:
  35    vector_deref_visitor()
  36       : progress(false)
  37    {
  38    }
  39
  40    virtual ~vector_deref_visitor()
  41    {
  42    }
  43
  44    virtual void handle_rvalue(ir_rvalue **rv);
  45    virtual ir_visitor_status visit_enter(ir_assignment *ir);
  46
  47    bool progress;
  48 };
  49
  50 } /* anonymous namespace */
  51
  52 ir_visitor_status
  53 vector_deref_visitor::visit_enter(ir_assignment *ir)
  54 {
  55    if (!ir->lhs || ir->lhs->ir_type != ir_type_dereference_array)
  56       return ir_rvalue_enter_visitor::visit_enter(ir);
  57
  58    ir_dereference_array *const deref = (ir_dereference_array *) ir->lhs;
  59    if (!deref->array->type->is_vector())
  60       return ir_rvalue_enter_visitor::visit_enter(ir);
  61
  62    ir_rvalue *const new_lhs = deref->array;
  63
  64    void *mem_ctx = ralloc_parent(ir);
  65    ir_constant *old_index_constant =
  66       deref->array_index->constant_expression_value(mem_ctx);
  67    if (!old_index_constant) {
  68       ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert,
  69                                            new_lhs->type,
  70                                            new_lhs->clone(mem_ctx, NULL),
  71                                            ir->rhs,
  72                                            deref->array_index);
  73       ir->write_mask = (1 << new_lhs->type->vector_elements) - 1;
  74       ir->set_lhs(new_lhs);
  75    } else if (new_lhs->ir_type != ir_type_swizzle) {
  76       ir->set_lhs(new_lhs);
  77       ir->write_mask = 1 << old_index_constant->get_uint_component(0);
  78    } else {
  79       /* If the "new" LHS is a swizzle, use the set_lhs helper to instead
  80        * swizzle the RHS.
  81        */
  82       unsigned component[1] = { old_index_constant->get_uint_component(0) };
  83       ir->set_lhs(new(mem_ctx) ir_swizzle(new_lhs, component, 1));
  84    }
  85
  86    return ir_rvalue_enter_visitor::visit_enter(ir);
  87 }
  88
  89 void
  90 vector_deref_visitor::handle_rvalue(ir_rvalue **rv)
  91 {
  92    if (*rv == NULL || (*rv)->ir_type != ir_type_dereference_array)
  93       return;
  94
  95    ir_dereference_array *const deref = (ir_dereference_array *) *rv;
  96    if (!deref->array->type->is_vector())
  97       return;
  98
  99    void *mem_ctx = ralloc_parent(deref);
 100    *rv = new(mem_ctx) ir_expression(ir_binop_vector_extract,
 101                                     deref->array,
 102                                     deref->array_index);
 103 }
 104
 105 bool
 106 lower_vector_derefs(gl_linked_shader *shader)
 107 {
 108    vector_deref_visitor v;
 109
 110    visit_list_elements(&v, shader->ir);
 111
 112    return v.progress;
 113 }