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 lower_vector.cpp
26 * IR lowering pass to remove some types of ir_quadop_vector
27 *
28 * \author Ian Romanick <ian.d.romanick@intel.com>
29 */
30
31 #include "ir.h"
32 #include "ir_rvalue_visitor.h"
33
34 namespace {
35
36 class lower_vector_visitor : public ir_rvalue_visitor {
37 public:
lower_vector_visitor()38 lower_vector_visitor() : dont_lower_swz(false), progress(false)
39 {
40 /* empty */
41 }
42
43 void handle_rvalue(ir_rvalue **rvalue);
44
45 /**
46 * Should SWZ-like expressions be lowered?
47 */
48 bool dont_lower_swz;
49
50 bool progress;
51 };
52
53 } /* anonymous namespace */
54
55 /**
56 * Determine if an IR expression tree looks like an extended swizzle
57 *
58 * Extended swizzles consist of access of a single vector source (with possible
59 * per component negation) and the constants -1, 0, or 1.
60 */
61 static bool
is_extended_swizzle(ir_expression * ir)62 is_extended_swizzle(ir_expression *ir)
63 {
64 /* Track any variables that are accessed by this expression.
65 */
66 ir_variable *var = NULL;
67
68 assert(ir->operation == ir_quadop_vector);
69
70 for (unsigned i = 0; i < ir->type->vector_elements; i++) {
71 ir_rvalue *op = ir->operands[i];
72
73 while (op != NULL) {
74 switch (op->ir_type) {
75 case ir_type_constant: {
76 const ir_constant *const c = op->as_constant();
77
78 if (!c->is_one() && !c->is_zero() && !c->is_negative_one())
79 return false;
80
81 op = NULL;
82 break;
83 }
84
85 case ir_type_dereference_variable: {
86 ir_dereference_variable *const d = (ir_dereference_variable *) op;
87
88 if ((var != NULL) && (var != d->var))
89 return false;
90
91 var = d->var;
92 op = NULL;
93 break;
94 }
95
96 case ir_type_expression: {
97 ir_expression *const ex = (ir_expression *) op;
98
99 if (ex->operation != ir_unop_neg)
100 return false;
101
102 op = ex->operands[0];
103 break;
104 }
105
106 case ir_type_swizzle:
107 op = ((ir_swizzle *) op)->val;
108 break;
109
110 default:
111 return false;
112 }
113 }
114 }
115
116 return true;
117 }
118
119 void
handle_rvalue(ir_rvalue ** rvalue)120 lower_vector_visitor::handle_rvalue(ir_rvalue **rvalue)
121 {
122 if (!*rvalue)
123 return;
124
125 ir_expression *expr = (*rvalue)->as_expression();
126 if ((expr == NULL) || (expr->operation != ir_quadop_vector))
127 return;
128
129 if (this->dont_lower_swz && is_extended_swizzle(expr))
130 return;
131
132 /* FINISHME: Is this the right thing to use for the ralloc context?
133 */
134 void *const mem_ctx = expr;
135
136 assert(expr->type->vector_elements == expr->num_operands);
137
138 /* Generate a temporary with the same type as the ir_quadop_operation.
139 */
140 ir_variable *const temp =
141 new(mem_ctx) ir_variable(expr->type, "vecop_tmp", ir_var_temporary);
142
143 this->base_ir->insert_before(temp);
144
145 /* Counter of the number of components collected so far.
146 */
147 unsigned assigned;
148
149 /* Write-mask in the destination that receives counted by 'assigned'.
150 */
151 unsigned write_mask;
152
153
154 /* Generate upto four assignments to that variable. Try to group component
155 * assignments together:
156 *
157 * - All constant components can be assigned at once.
158 * - All assigments of components from a single variable with the same
159 * unary operator can be assigned at once.
160 */
161 ir_constant_data d = { { 0 } };
162
163 assigned = 0;
164 write_mask = 0;
165 for (unsigned i = 0; i < expr->type->vector_elements; i++) {
166 const ir_constant *const c = expr->operands[i]->as_constant();
167
168 if (c == NULL)
169 continue;
170
171 switch (expr->type->base_type) {
172 case GLSL_TYPE_UINT: d.u[assigned] = c->value.u[0]; break;
173 case GLSL_TYPE_INT: d.i[assigned] = c->value.i[0]; break;
174 case GLSL_TYPE_FLOAT: d.f[assigned] = c->value.f[0]; break;
175 case GLSL_TYPE_BOOL: d.b[assigned] = c->value.b[0]; break;
176 default: assert(!"Should not get here."); break;
177 }
178
179 write_mask |= (1U << i);
180 assigned++;
181 }
182
183 assert((write_mask == 0) == (assigned == 0));
184
185 /* If there were constant values, generate an assignment.
186 */
187 if (assigned > 0) {
188 ir_constant *const c =
189 new(mem_ctx) ir_constant(glsl_type::get_instance(expr->type->base_type,
190 assigned, 1),
191 &d);
192 ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
193 ir_assignment *const assign =
194 new(mem_ctx) ir_assignment(lhs, c, NULL, write_mask);
195
196 this->base_ir->insert_before(assign);
197 }
198
199 /* FINISHME: This should try to coalesce assignments.
200 */
201 for (unsigned i = 0; i < expr->type->vector_elements; i++) {
202 if (expr->operands[i]->ir_type == ir_type_constant)
203 continue;
204
205 ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
206 ir_assignment *const assign =
207 new(mem_ctx) ir_assignment(lhs, expr->operands[i], NULL, (1U << i));
208
209 this->base_ir->insert_before(assign);
210 assigned++;
211 }
212
213 assert(assigned == expr->type->vector_elements);
214
215 *rvalue = new(mem_ctx) ir_dereference_variable(temp);
216 this->progress = true;
217 }
218
219 bool
lower_quadop_vector(exec_list * instructions,bool dont_lower_swz)220 lower_quadop_vector(exec_list *instructions, bool dont_lower_swz)
221 {
222 lower_vector_visitor v;
223
224 v.dont_lower_swz = dont_lower_swz;
225 visit_list_elements(&v, instructions);
226
227 return v.progress;
228 }
229