1 files changed, 44 insertions, 0 deletions
diff --git a/tensorflow/compiler/xla/service/cpu/cpu_instruction_fusion.cc b/tensorflow/compiler/xla/service/cpu/cpu_instruction_fusion.cc
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+++ b/tensorflow/compiler/xla/service/cpu/cpu_instruction_fusion.cc
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+/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/compiler/xla/service/cpu/cpu_instruction_fusion.h"
+
+#include "tensorflow/compiler/xla/service/hlo_opcode.h"
+
+namespace xla {
+namespace cpu {
+
+bool CpuInstructionFusion::ShouldFuse(HloInstruction* consumer,
+                                      int64 operand_index) {
+  HloInstruction* producer = consumer->mutable_operand(operand_index);
+
+  // Condition for consumer: must be elementwise or a fusion op
+  // (which necessarily only contains elementwise operations)
+  if (!(consumer->opcode() == HloOpcode::kFusion ||
+        consumer->IsElementwise())) {
+    return false;
+  }
+
+  // Producer or consumer cannot be Map. Maps are technically elementwise but
+  // of a slightly different form (call instead of a computation). These are not
+  // yet supported in the CPU backend.
+  return producer->IsElementwise() && producer->operand_count() > 0 &&
+         producer->opcode() != HloOpcode::kMap &&
+         consumer->opcode() != HloOpcode::kMap &&
+         InstructionFusion::ShouldFuse(consumer, operand_index);
+}
+
+}  // namespace cpu
+}  // namespace xla