1 /* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
2
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9 Unless required by applicable law or agreed to in writing, software
10 distributed under the License is distributed on an "AS IS" BASIS,
11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 See the License for the specific language governing permissions and
13 limitations under the License.
14 ==============================================================================*/
15
16 #include "tensorflow/compiler/xla/service/loop_schedule_linearizer.h"
17
18 #include <set>
19
20 #include "tensorflow/compiler/xla/debug_options_flags.h"
21 #include "tensorflow/compiler/xla/literal.h"
22 #include "tensorflow/compiler/xla/service/copy_insertion.h"
23 #include "tensorflow/compiler/xla/service/hlo_computation.h"
24 #include "tensorflow/compiler/xla/service/hlo_instruction.h"
25 #include "tensorflow/compiler/xla/service/hlo_matchers.h"
26 #include "tensorflow/compiler/xla/service/hlo_module.h"
27 #include "tensorflow/compiler/xla/service/hlo_opcode.h"
28 #include "tensorflow/compiler/xla/service/hlo_runner.h"
29 #include "tensorflow/compiler/xla/shape_util.h"
30 #include "tensorflow/compiler/xla/test.h"
31 #include "tensorflow/compiler/xla/test_helpers.h"
32 #include "tensorflow/compiler/xla/tests/hlo_test_base.h"
33 #include "tensorflow/compiler/xla/xla_data.pb.h"
34 #include "tensorflow/core/platform/test_benchmark.h"
35
36 namespace xla {
37 namespace {
38
CountCopies(const HloComputation & computation)39 int64_t CountCopies(const HloComputation& computation) {
40 int64_t count = 0;
41 for (const auto& instruction : computation.instructions()) {
42 if (instruction->opcode() == HloOpcode::kCopy) {
43 count++;
44 }
45 }
46 return count;
47 }
48
CountCopies(const HloModule & module)49 int64_t CountCopies(const HloModule& module) {
50 int64_t count = 0;
51 for (const auto& computation : module.computations()) {
52 count += CountCopies(*computation);
53 }
54 return count;
55 }
56
CountControlEdges(const HloComputation & computation)57 int64_t CountControlEdges(const HloComputation& computation) {
58 int64_t count = 0;
59 for (const auto& instruction : computation.instructions()) {
60 count += instruction->control_successors().size();
61 }
62 return count;
63 }
64
CountControlEdges(const HloModule & module)65 int64_t CountControlEdges(const HloModule& module) {
66 int64_t count = 0;
67 for (const auto& computation : module.computations()) {
68 count += CountControlEdges(*computation);
69 }
70 return count;
71 }
72
73 class LoopScheduleLinearizerTest : public HloTestBase {
74 protected:
InsertCopies(HloModule * module)75 void InsertCopies(HloModule* module) {
76 LoopScheduleLinearizer loop_schedule_linearizer;
77 ASSERT_IS_OK(loop_schedule_linearizer.Run(module).status());
78
79 CopyInsertion copy_insertion;
80 ASSERT_IS_OK(copy_insertion.Run(module).status());
81 }
82 };
83
TEST_F(LoopScheduleLinearizerTest,NoExtraCopiesRequired)84 TEST_F(LoopScheduleLinearizerTest, NoExtraCopiesRequired) {
85 absl::string_view hlo_string = R"(
86 HloModule module
87
88 while_body {
89 input = (s32[], s32[]) parameter(0)
90 counter = s32[] get-tuple-element(input), index=0
91 buffer = s32[] get-tuple-element(input), index=1
92
93 one = s32[] constant(1)
94
95 updated_counter = s32[] add(counter, one)
96
97 updated_buffer = s32[] add(buffer, counter)
98 ROOT out = (s32[], s32[]) tuple(updated_counter, updated_buffer)
99 }
100
101 while_cond {
102 input = (s32[], s32[]) parameter(0)
103 counter = s32[] get-tuple-element(input), index=0
104 bound = s32[] constant(100)
105 ROOT cmp = pred[] compare(counter, bound), direction=LT
106 }
107
108 ENTRY entry {
109 zero = s32[] constant(0)
110 buffer = s32[] parameter(0)
111 while_input = (s32[], s32[]) tuple(zero, buffer)
112 ROOT out = (s32[], s32[]) while(while_input), condition=while_cond, body=while_body
113 }
114
115 )";
116 TF_ASSERT_OK_AND_ASSIGN(std::unique_ptr<HloModule> module,
117 ParseAndReturnVerifiedModule(hlo_string));
118 InsertCopies(module.get());
119 EXPECT_EQ(CountCopies(
120 *module->entry_computation()->root_instruction()->while_body()),
121 0);
122 EXPECT_EQ(CountControlEdges(
123 *module->entry_computation()->root_instruction()->while_body()),
124 1);
125 }
126
127 } // namespace
128 } // namespace xla
129