1 files changed, 3 insertions, 82 deletions

diff --git a/tensorflow/compiler/xla/service/copy_insertion.cc b/tensorflow/compiler/xla/service/copy_insertion.cc
index cfe025fdd1..f35324aa35 100644
--- a/tensorflow/compiler/xla/service/copy_insertion.cc
+++ b/tensorflow/compiler/xla/service/copy_insertion.cc
@@ -40,12 +40,10 @@ namespace {
 
 using absl::StrAppend;
 
-bool IsReadonlyEntryParameterValue(const HloValue& value) {
+bool IsEntryParameterValue(const HloValue& value) {
   const HloComputation* computation = value.defining_instruction()->parent();
   return value.defining_instruction()->opcode() == HloOpcode::kParameter &&
-         computation == computation->parent()->entry_computation() &&
-         !computation->parent()->input_output_alias_config().ParameterHasAlias(
-             value.defining_instruction()->parameter_number());
+         computation == computation->parent()->entry_computation();
 }
 
 bool IsConstantValue(const HloValue& value) {
@@ -53,7 +51,7 @@ bool IsConstantValue(const HloValue& value) {
 }
 
 bool ValueIsReadOnly(const HloValue& value) {
-  return IsConstantValue(value) || IsReadonlyEntryParameterValue(value);
+  return IsConstantValue(value) || IsEntryParameterValue(value);
 }
 
 // Data structure describing the action which should be taken on parts of a
@@ -334,81 +332,6 @@ Status AddCopiesForConditional(const HloAliasAnalysis& alias_analysis,
   return Status::OK();
 }
 
-// Conservatively adds copies before root instruction of entry computation and
-// each aliased parameter to resolve interference of aliased input and output
-// buffer. We later rely on the CopyRemover to drop the unnecessary ones.
-Status AddCopiesForAliasedInputOutputs(HloModule* module) {
-  HloComputation* entry = module->entry_computation();
-  HloInstruction* root = entry->root_instruction();
-
-  ShapeTree<bool> output_indices_to_copy(root->shape());
-  std::vector<ShapeTree<HloInstruction*>> copied_parameters;
-  bool has_alias = false;
-  for (auto* param : entry->parameter_instructions()) {
-    bool param_has_alias = false;
-    ShapeTree<bool> param_indices_to_copy(param->shape());
-
-    module->input_output_alias_config().ForEachAlias(
-        [&](const ShapeIndex& output_index, int64 param_number,
-            const ShapeIndex& param_index) {
-          if (param_number == param->parameter_number()) {
-            param_has_alias = true;
-            *(param_indices_to_copy.mutable_element(param_index)) = true;
-            *(output_indices_to_copy.mutable_element(output_index)) = true;
-          }
-        });
-
-    if (!param_has_alias) {
-      continue;
-    }
-
-    has_alias = true;
-    // Store a snapshot of users before DeepCopyInstruction, as
-    // DeepCopyInstruction introduces new users of the instruction.
-    std::vector<HloInstruction*> users = param->users();
-    ShapeTree<HloInstruction*> param_copy_tree(param->shape(),
-                                               /*init_value=*/nullptr);
-    TF_ASSIGN_OR_RETURN(HloInstruction * copied,
-                        entry->DeepCopyInstruction(
-                            param, &param_indices_to_copy, &param_copy_tree));
-    for (HloInstruction* user : users) {
-      TF_RETURN_IF_ERROR(param->ReplaceUseWith(user, copied));
-    }
-
-    copied_parameters.push_back(param_copy_tree);
-  }
-
-  if (!has_alias) {
-    return Status::OK();
-  }
-
-  // Add copies before root instruction.
-  ShapeTree<HloInstruction*> output_copy_tree(root->shape(),
-                                              /*init_value=*/nullptr);
-
-  TF_ASSIGN_OR_RETURN(HloInstruction * root_copied,
-                      root->parent()->DeepCopyInstruction(
-                          root, &output_indices_to_copy, &output_copy_tree));
-
-  // Add control dependencies between the input/output copies.
-  TF_RETURN_IF_ERROR(module->input_output_alias_config().ForEachAliasWithStatus(
-      [&](const ShapeIndex& output_index, int64 param_number,
-          const ShapeIndex& input_index) -> Status {
-        HloInstruction* from =
-            copied_parameters[param_number].element(input_index);
-        HloInstruction* to = output_copy_tree.element(output_index);
-
-        TF_RET_CHECK(from != nullptr);
-        TF_RET_CHECK(to != nullptr);
-        TF_RETURN_IF_ERROR(from->AddControlDependencyTo(to));
-        return Status::OK();
-      }));
-
-  entry->set_root_instruction(root_copied);
-
-  return Status::OK();
-}
-
 // Removes any control dependencies to or from the given instruction.
 Status StripControlDependenciesFrom(HloInstruction* instruction) {
   while (!instruction->control_successors().empty()) {
@@ -1030,8 +953,6 @@ Status CopyInsertion::AddCopiesToResolveInterference(HloModule* module) {
       }
     }
   }
-
-  TF_RETURN_IF_ERROR(AddCopiesForAliasedInputOutputs(module));
   return Status::OK();
 }