aboutsummaryrefslogtreecommitdiffstats
path: root/src/glsl/lower_vector.cpp
blob: 9172b6af7b504b9401ef1848616a6739f50c23a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
/*
 * Copyright © 2010 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/**
 * \file lower_vector.cpp
 * IR lowering pass to remove some types of ir_quadop_vector
 *
 * \author Ian Romanick <ian.d.romanick@intel.com>
 */

#include "ir.h"
#include "ir_rvalue_visitor.h"

namespace {

class lower_vector_visitor : public ir_rvalue_visitor {
public:
   lower_vector_visitor() : progress(false)
   {
      /* empty */
   }

   void handle_rvalue(ir_rvalue **rvalue);

   /**
    * Should SWZ-like expressions be lowered?
    */
   bool dont_lower_swz;

   bool progress;
};

} /* anonymous namespace */

/**
 * Determine if an IR expression tree looks like an extended swizzle
 *
 * Extended swizzles consist of access of a single vector source (with possible
 * per component negation) and the constants -1, 0, or 1.
 */
bool
is_extended_swizzle(ir_expression *ir)
{
   /* Track any variables that are accessed by this expression.
    */
   ir_variable *var = NULL;

   assert(ir->operation == ir_quadop_vector);

   for (unsigned i = 0; i < ir->type->vector_elements; i++) {
      ir_rvalue *op = ir->operands[i];

      while (op != NULL) {
	 switch (op->ir_type) {
	 case ir_type_constant: {
	    const ir_constant *const c = op->as_constant();

	    if (!c->is_one() && !c->is_zero() && !c->is_negative_one())
	       return false;

	    op = NULL;
	    break;
	 }

	 case ir_type_dereference_variable: {
	    ir_dereference_variable *const d = (ir_dereference_variable *) op;

	    if ((var != NULL) && (var != d->var))
	       return false;

	    var = d->var;
	    op = NULL;
	    break;
	 }

	 case ir_type_expression: {
	    ir_expression *const ex = (ir_expression *) op;

	    if (ex->operation != ir_unop_neg)
	       return false;

	    op = ex->operands[0];
	    break;
	 }

	 case ir_type_swizzle:
	    op = ((ir_swizzle *) op)->val;
	    break;

	 default:
	    return false;
	 }
      }
   }

   return true;
}

void
lower_vector_visitor::handle_rvalue(ir_rvalue **rvalue)
{
   if (!*rvalue)
      return;

   ir_expression *expr = (*rvalue)->as_expression();
   if ((expr == NULL) || (expr->operation != ir_quadop_vector))
      return;

   if (this->dont_lower_swz && is_extended_swizzle(expr))
      return;

   /* FINISHME: Is this the right thing to use for the ralloc context?
    */
   void *const mem_ctx = expr;

   assert(expr->type->vector_elements == expr->get_num_operands());

   /* Generate a temporary with the same type as the ir_quadop_operation.
    */
   ir_variable *const temp =
      new(mem_ctx) ir_variable(expr->type, "vecop_tmp", ir_var_temporary);

   this->base_ir->insert_before(temp);

   /* Counter of the number of components collected so far.
    */
   unsigned assigned;

   /* Write-mask in the destination that receives counted by 'assigned'.
    */
   unsigned write_mask;


   /* Generate upto four assignments to that variable.  Try to group component
    * assignments together:
    *
    * - All constant components can be assigned at once.
    * - All assigments of components from a single variable with the same
    *   unary operator can be assigned at once.
    */
   ir_constant_data d = { { 0 } };

   assigned = 0;
   write_mask = 0;
   for (unsigned i = 0; i < expr->type->vector_elements; i++) {
      const ir_constant *const c = expr->operands[i]->as_constant();

      if (c == NULL)
	 continue;

      switch (expr->type->base_type) {
      case GLSL_TYPE_UINT:  d.u[assigned] = c->value.u[0]; break;
      case GLSL_TYPE_INT:   d.i[assigned] = c->value.i[0]; break;
      case GLSL_TYPE_FLOAT: d.f[assigned] = c->value.f[0]; break;
      case GLSL_TYPE_BOOL:  d.b[assigned] = c->value.b[0]; break;
      default:              assert(!"Should not get here."); break;
      }

      write_mask |= (1U << i);
      assigned++;
   }

   assert((write_mask == 0) == (assigned == 0));

   /* If there were constant values, generate an assignment.
    */
   if (assigned > 0) {
      ir_constant *const c =
	 new(mem_ctx) ir_constant(glsl_type::get_instance(expr->type->base_type,
							  assigned, 1),
				  &d);
      ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
      ir_assignment *const assign =
	 new(mem_ctx) ir_assignment(lhs, c, NULL, write_mask);

      this->base_ir->insert_before(assign);
   }

   /* FINISHME: This should try to coalesce assignments.
    */
   for (unsigned i = 0; i < expr->type->vector_elements; i++) {
      if (expr->operands[i]->ir_type == ir_type_constant)
	 continue;

      ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
      ir_assignment *const assign =
	 new(mem_ctx) ir_assignment(lhs, expr->operands[i], NULL, (1U << i));

      this->base_ir->insert_before(assign);
      assigned++;
   }

   assert(assigned == expr->type->vector_elements);

   *rvalue = new(mem_ctx) ir_dereference_variable(temp);
   this->progress = true;
}

bool
lower_quadop_vector(exec_list *instructions, bool dont_lower_swz)
{
   lower_vector_visitor v;

   v.dont_lower_swz = dont_lower_swz;
   visit_list_elements(&v, instructions);

   return v.progress;
}