rollback a broken CL

Reverts 5bddc28fd5

PiperOrigin-RevId: 800789392

third_party/xla/xla/hlo/transforms/simplifiers/BUILD

@@ -296,11 +296,12 @@ cc_library(
         "//xla:util",
         "//xla/hlo/analysis:alias_info",
         "//xla/hlo/analysis:hlo_alias_analysis",
-        "//xla/hlo/analysis:hlo_dataflow_analysis",
+        "//xla/hlo/analysis:tuple_points_to_analysis",
         "//xla/hlo/ir:hlo",
         "//xla/hlo/pass:hlo_pass",
         "//xla/service:buffer_value",
         "//xla/service:hlo_value",
+        "//xla/service:logical_buffer",
         "//xla/service/heap_simulator",
         "//xla/tsl/platform:errors",
         "//xla/tsl/platform:logging",

third_party/xla/xla/hlo/transforms/simplifiers/hlo_memory_scheduler.cc

@@ -36,7 +36,7 @@ limitations under the License.
 #include "absl/strings/string_view.h"
 #include "xla/hlo/analysis/alias_info.h"
 #include "xla/hlo/analysis/hlo_alias_analysis.h"
-#include "xla/hlo/analysis/hlo_dataflow_analysis.h"
+#include "xla/hlo/analysis/tuple_points_to_analysis.h"
 #include "xla/hlo/ir/dfs_hlo_visitor_with_default.h"
 #include "xla/hlo/ir/hlo_computation.h"
 #include "xla/hlo/ir/hlo_instruction.h"
@@ -45,6 +45,7 @@ limitations under the License.
 #include "xla/service/buffer_value.h"
 #include "xla/service/heap_simulator/heap_simulator.h"
 #include "xla/service/hlo_value.h"
+#include "xla/service/logical_buffer.h"
 #include "xla/shape_util.h"
 #include "xla/tsl/platform/errors.h"
 #include "xla/tsl/platform/logging.h"
@@ -92,9 +93,10 @@ class ListScheduler {
   // Construct and return a memory-minimizing sequence of HLO instructions
   // containing the given HLO computation.
   static absl::StatusOr<HloInstructionSequence> Run(
-      HloComputation* computation, const HloAliasAnalysis& alias_analysis,
+      HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const BufferValue::SizeFunction& size_function) {
-    ListScheduler scheduler(computation, alias_analysis, size_function);
+    ListScheduler scheduler(computation, points_to_analysis, size_function);
     return scheduler.CreateSchedule();
   }
 
@@ -114,57 +116,56 @@ class ListScheduler {
   using Priority = std::pair<int64_t, int64_t>;
 
   ListScheduler(HloComputation* computation,
-                const HloAliasAnalysis& alias_analysis,
+                const TuplePointsToAnalysis& points_to_analysis,
                 const BufferValue::SizeFunction& size_function)
       : computation_(computation),
-        alias_analysis_(alias_analysis),
+        points_to_analysis_(points_to_analysis),
         size_function_(size_function) {
-    // Create a map containing the HloValue uses for each HLO instruction. An
+    // Create a map containing the LogicalBuffer uses for each HLO
-    // HLO instruction "uses" a HloValue if the HloValue is in an operand of the
+    // instruction. An HLO instruction "uses" a LogicalBuffer if the
-    // instruction as indicated by HloDataflowAnalysis.
+    // LogicalBuffer is in an operand of the instruction as indicated by
-    const HloDataflowAnalysis& dataflow_analysis =
+    // points-to analysis.
-        alias_analysis.dataflow_analysis();
-    absl::flat_hash_set<const HloValue*> computation_values;
     for (auto* instruction : computation->instructions()) {
-      dataflow_analysis.GetInstructionValueSet(instruction)
+      absl::flat_hash_set<const LogicalBuffer*> instr_uses;
-          .ForEachElement(
-              [&](const ShapeIndex& /*index*/, const HloValueSet& value_set) {
-                computation_values.insert(value_set.values().begin(),
-                                          value_set.values().end());
-              });
-      absl::flat_hash_set<const HloValue*> instr_uses;
       for (auto* operand : instruction->operands()) {
-        dataflow_analysis.GetInstructionValueSet(operand).ForEachElement(
+        points_to_analysis.GetPointsToSet(operand).ForEachElement(
-            [&](const ShapeIndex& /*index*/, const HloValueSet& value_set) {
+            [&](const ShapeIndex& /*index*/,
-              instr_uses.insert(value_set.values().begin(),
+                const PointsToSet::BufferList& buffers) {
-                                value_set.values().end());
+              instr_uses.insert(buffers.begin(), buffers.end());
             });
       }
-      value_uses_[instruction] =
+      buffer_uses_[instruction] = std::vector<const LogicalBuffer*>(
-          std::vector<const HloValue*>(instr_uses.begin(), instr_uses.end());
+          instr_uses.begin(), instr_uses.end());
     }
 
     // Create map containing the number of unscheduled uses (hlo instructions)
-    // of each HloValue.
+    // of each logical buffer.
-    unscheduled_use_count_.reserve(computation_values.size());
+    unscheduled_use_count_.reserve(points_to_analysis.num_logical_buffers());
-    for (const HloValue* value : computation_values) {
+    for (auto* instruction : computation->instructions()) {
-      // HloValues live out of the computation have an implicit use at the end
+      for (auto* buffer :
-      // of the computation. Therefore we initialize `unscheduled_use_count_` to
+           points_to_analysis.GetBuffersDefinedByInstruction(instruction)) {
-      // 1 in such cases.
+        unscheduled_use_count_[buffer] = 0;
-      unscheduled_use_count_[value] =
+      }
-          alias_analysis.ValueLivesOut(*value) ? 1 : 0;
     }
     for (auto* instruction : computation->instructions()) {
-      for (const HloValue* value : value_uses_.at(instruction)) {
+      for (const LogicalBuffer* buffer : buffer_uses_.at(instruction)) {
-        ++unscheduled_use_count_[value];
+        ++unscheduled_use_count_[buffer];
       }
     }
+
+    // Buffers live out of the computation have an implicit use at the end of
+    // the computation.
+    for (const LogicalBuffer* live_out_buffer :
+         points_to_analysis.GetPointsToSet(computation->root_instruction())
+             .CreateFlattenedSet()) {
+      ++unscheduled_use_count_[live_out_buffer];
+    }
   }
 
-  // Returns whether the memory used by the given HloValue should be ignored by
+  // Returns whether the memory used by the given buffer should be ignored by
   // the scheduling heuristic.
-  static bool IgnoreValue(const HloValue& value) {
+  static bool IgnoreBuffer(const LogicalBuffer& buffer) {
-    return IgnoreInstruction(*value.instruction());
+    return IgnoreInstruction(*buffer.instruction());
   }
 
   // An entry in the worklist used by CreateSchedule.  Corresponds to one
@@ -180,7 +181,7 @@ class ListScheduler {
     // U is the number of uses of B that have not yet been scheduled. This pair
     // is a pointer into the unscheduled_use_count_ map, so it gets updated for
     // free when we update counts in the map.
-    std::vector<const std::pair<const HloValue* const, int64_t>*>
+    std::vector<const std::pair<const LogicalBuffer* const, int64_t>*>
         used_buffer_unscheduled_use_counts;
   };
 
@@ -190,20 +191,18 @@ class ListScheduler {
     entry.instruction = instruction;
 
     entry.bytes_defined = 0;
-    HloValueSet value_set =
+    for (auto* buffer :
-        alias_analysis_.dataflow_analysis().GetFlattenedValueSet(instruction);
+         points_to_analysis_.GetBuffersDefinedByInstruction(instruction)) {
-    for (const HloValue* value : value_set.values()) {
+      if (!IgnoreBuffer(*buffer)) {
-      if (!IgnoreInstruction(*instruction) &&
+        entry.bytes_defined += size_function_(*buffer);
-          value->instruction() == instruction) {
-        entry.bytes_defined += size_function_(*value);
       }
     }
 
-    for (auto* value : value_uses_.at(instruction)) {
+    for (auto* buffer : buffer_uses_.at(instruction)) {
-      if (IgnoreValue(*value)) {
+      if (IgnoreBuffer(*buffer)) {
         continue;
       }
-      auto unscheduled_use_count_it = unscheduled_use_count_.find(value);
+      auto unscheduled_use_count_it = unscheduled_use_count_.find(buffer);
       CHECK(unscheduled_use_count_it != unscheduled_use_count_.end());
       entry.used_buffer_unscheduled_use_counts.push_back(
           &*unscheduled_use_count_it);
@@ -309,9 +308,9 @@ class ListScheduler {
       scheduled_instructions_.insert(best);
 
       bool adjust_ready_queue = false;
-      // Update the unscheduled uses of the HloValues.
+      // Update the unscheduled uses of the logical buffers.
-      for (const HloValue* value : value_uses_.at(best)) {
+      for (const LogicalBuffer* buffer : buffer_uses_.at(best)) {
-        int64_t& count = unscheduled_use_count_[value];
+        int64_t& count = unscheduled_use_count_[buffer];
         CHECK_GT(count, 0);
         --count;
         if (count == 1) {
@@ -335,7 +334,7 @@ class ListScheduler {
       for (HloInstruction* succ : best->control_successors()) {
         update_pred_count(succ);
       }
-      // The unscheduled use count for a HloValue has changed to 1, so the
+      // The unscheduled use count for a buffer has changed to 1, so the
       // priorities of some ready instructions may go up. We update them in the
       // ready queue, so that they can appear earlier.
       if (adjust_ready_queue) {
@@ -361,24 +360,23 @@ class ListScheduler {
         }
       }
     }
-    CHECK_EQ(schedule.size(), computation_->instruction_count())
+    CHECK_EQ(schedule.size(), computation_->instruction_count());
-        << "There could be a cycle in the HLO graph";
     CHECK_EQ(scheduled_instructions_.size(), computation_->instruction_count());
 
     return schedule;
   }
 
   HloComputation* computation_;
-  const HloAliasAnalysis& alias_analysis_;
+  const TuplePointsToAnalysis& points_to_analysis_;
   const BufferValue::SizeFunction& size_function_;
 
-  // A map containing the HloValue that each instruction uses.
+  // A map containing the LogicalBuffers that each instruction uses.
-  absl::flat_hash_map<const HloInstruction*, std::vector<const HloValue*>>
+  absl::flat_hash_map<const HloInstruction*, std::vector<const LogicalBuffer*>>
-      value_uses_;
+      buffer_uses_;
 
   // A map containing the count of unscheduled HLOs which using a particular
-  // HloValue.
+  // LogicalBuffer.
-  absl::flat_hash_map<const HloValue*, int64_t> unscheduled_use_count_;
+  absl::flat_hash_map<const LogicalBuffer*, int64_t> unscheduled_use_count_;
 
   // Set of instructions which have been scheduled.
   absl::flat_hash_set<const HloInstruction*> scheduled_instructions_;
@@ -398,7 +396,8 @@ int64_t SumBufferSizes(const HloInstruction* hlo, const HloValueSet& value_set,
 }  // namespace
 
 absl::StatusOr<HloSchedule> ComputationSchedulerAlgorithm::Run(
-    const HloModule* module, const HloAliasAnalysis& alias_analysis,
+    const HloModule* module, const TuplePointsToAnalysis& points_to_analysis,
+    const HloAliasAnalysis& alias_analysis,
     const absl::flat_hash_set<absl::string_view>& execution_threads,
     int64_t* peak_memory) const {
   HloSchedule schedule(module);
@@ -406,7 +405,7 @@ absl::StatusOr<HloSchedule> ComputationSchedulerAlgorithm::Run(
        module->MakeComputationPostOrder(execution_threads)) {
     if (!computation->IsFusionComputation()) {
       TF_ASSIGN_OR_RETURN(HloInstructionSequence computation_sequence,
-                          Run(computation, alias_analysis));
+                          Run(computation, points_to_analysis, alias_analysis));
       if (postprocessor_) {
         computation_sequence = postprocessor_(computation_sequence);
       }
@@ -423,6 +422,7 @@ absl::StatusOr<HloSchedule> ComputationSchedulerAlgorithm::Run(
 
 absl::StatusOr<HloInstructionSequence> DFSMemoryScheduler::Run(
     HloComputation* computation,
+    const TuplePointsToAnalysis& points_to_analysis,
     const HloAliasAnalysis& alias_analysis) const {
   // These variables are a hack to prevent overflows.
   int64_t cumulative_total_size = 0;
@@ -501,6 +501,7 @@ absl::StatusOr<HloInstructionSequence> DFSMemoryScheduler::Run(
 
 absl::StatusOr<HloInstructionSequence> BFScheduler::Run(
     HloComputation* computation,
+    const TuplePointsToAnalysis& points_to_analysis,
     const HloAliasAnalysis& alias_analysis) const {
   // Index of HloInstruction in the `computation`.
   absl::flat_hash_map<const HloInstruction*, int64_t> inst_index;
@@ -554,18 +555,21 @@ absl::StatusOr<HloInstructionSequence> BFScheduler::Run(
 
 absl::StatusOr<HloInstructionSequence> ListMemoryScheduler::Run(
     HloComputation* computation,
+    const TuplePointsToAnalysis& points_to_analysis,
     const HloAliasAnalysis& alias_analysis) const {
-  return ListScheduler::Run(computation, alias_analysis, size_function_);
+  return ListScheduler::Run(computation, points_to_analysis, size_function_);
 }
 
 absl::StatusOr<HloInstructionSequence> PostOrderScheduler::Run(
     HloComputation* computation,
+    const TuplePointsToAnalysis& points_to_analysis,
     const HloAliasAnalysis& alias_analysis) const {
   return HloInstructionSequence(computation->MakeInstructionPostOrder());
 }
 
 absl::StatusOr<HloSchedule> DefaultMemoryScheduler::Run(
-    const HloModule* module, const HloAliasAnalysis& alias_analysis,
+    const HloModule* module, const TuplePointsToAnalysis& points_to_analysis,
+    const HloAliasAnalysis& alias_analysis,
     const absl::flat_hash_set<absl::string_view>& execution_threads,
     int64_t* peak_memory) const {
   // We try a few schedulers and choose whichever returns a lower min-memory,
@@ -577,22 +581,24 @@ absl::StatusOr<HloSchedule> DefaultMemoryScheduler::Run(
   // List wins for most of our benchmarks; postorder-based schedulers win for
   // some RNNs.
   int64_t list_memory;
-  TF_ASSIGN_OR_RETURN(HloSchedule list_sequence,
+  TF_ASSIGN_OR_RETURN(
-                      list_scheduler_.Run(module, alias_analysis,
+      HloSchedule list_sequence,
-                                          execution_threads, &list_memory));
+      list_scheduler_.Run(module, points_to_analysis, alias_analysis,
+                          execution_threads, &list_memory));
   VLOG(2) << "Min-memory list sequence: " << HumanReadableNumBytes(list_memory);
 
   int64_t dfs_memory;
-  TF_ASSIGN_OR_RETURN(HloSchedule dfs_sequence,
+  TF_ASSIGN_OR_RETURN(
-                      dfs_scheduler_.Run(module, alias_analysis,
+      HloSchedule dfs_sequence,
-                                         execution_threads, &dfs_memory));
+      dfs_scheduler_.Run(module, points_to_analysis, alias_analysis,
+                         execution_threads, &dfs_memory));
   VLOG(2) << "Min-memory dfs sequence: " << HumanReadableNumBytes(dfs_memory);
 
   int64_t post_order_memory;
   TF_ASSIGN_OR_RETURN(
       HloSchedule post_order_sequence,
-      post_order_scheduler_.Run(module, alias_analysis, execution_threads,
+      post_order_scheduler_.Run(module, points_to_analysis, alias_analysis,
-                                &post_order_memory));
+                                execution_threads, &post_order_memory));
   VLOG(2) << "Min-memory post order sequence: "
           << HumanReadableNumBytes(post_order_memory);
 
@@ -624,12 +630,15 @@ absl::StatusOr<HloSchedule> ScheduleModule(
     return absl::StrFormat("XlaMemoryScheduler:#module=%s,program_id=%d#",
                            module->name(), module->unique_id());
   });
+  TF_ASSIGN_OR_RETURN(std::unique_ptr<TuplePointsToAnalysis> points_to_analysis,
+                      TuplePointsToAnalysis::Run(module));
   TF_ASSIGN_OR_RETURN(std::unique_ptr<HloAliasAnalysis> alias_analysis,
                       HloAliasAnalysis::Run(module, algorithm.alias_info()));
 
   TF_ASSIGN_OR_RETURN(
       HloSchedule schedule,
-      algorithm.Run(module, *alias_analysis, execution_threads, peak_memory));
+      algorithm.Run(module, *points_to_analysis, *alias_analysis,
+                    execution_threads, peak_memory));
 
   TF_RETURN_IF_ERROR(schedule.Verify());
 

third_party/xla/xla/hlo/transforms/simplifiers/hlo_memory_scheduler.h

@@ -26,6 +26,7 @@ limitations under the License.
 #include "absl/strings/string_view.h"
 #include "xla/hlo/analysis/alias_info.h"
 #include "xla/hlo/analysis/hlo_alias_analysis.h"
+#include "xla/hlo/analysis/tuple_points_to_analysis.h"
 #include "xla/hlo/ir/hlo_instruction.h"
 #include "xla/hlo/ir/hlo_module.h"
 #include "xla/hlo/ir/hlo_schedule.h"
@@ -38,13 +39,16 @@ namespace xla {
 // 'module' given a points-to analysis result that describes buffer aliasing.
 // peak_memory (may be nullptr) is set to the peak memory of the resulting
 // schedule according to the HeapSimulator.
+//
+// TODO(yunxing): Cleanup usage of TuplePointsToAnalysis.
 class ModuleSchedulerAlgorithm {
  public:
   explicit ModuleSchedulerAlgorithm(const AliasInfo* alias_info)
       : alias_info_(alias_info) {}
   virtual ~ModuleSchedulerAlgorithm() = default;
   virtual absl::StatusOr<HloSchedule> Run(
-      const HloModule* module, const HloAliasAnalysis& alias_analysis,
+      const HloModule* module, const TuplePointsToAnalysis& points_to_analysis,
+      const HloAliasAnalysis& alias_analysis,
       const absl::flat_hash_set<absl::string_view>& execution_threads,
       int64_t* peak_memory) const = 0;
 
@@ -68,9 +72,11 @@ class ComputationSchedulerAlgorithm : public ModuleSchedulerAlgorithm {
  public:
   virtual absl::StatusOr<HloInstructionSequence> Run(
       HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const HloAliasAnalysis& alias_analysis) const = 0;
   absl::StatusOr<HloSchedule> Run(
-      const HloModule* module, const HloAliasAnalysis& alias_analysis,
+      const HloModule* module, const TuplePointsToAnalysis& points_to_analysis,
+      const HloAliasAnalysis& alias_analysis,
       const absl::flat_hash_set<absl::string_view>& execution_threads,
       int64_t* peak_memory) const override;
 
@@ -99,6 +105,7 @@ class ListMemoryScheduler : public ComputationSchedulerAlgorithm {
   using ModuleSchedulerAlgorithm::Run;
   absl::StatusOr<HloInstructionSequence> Run(
       HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const HloAliasAnalysis& alias_analysis) const override;
 };
 
@@ -113,6 +120,7 @@ class DFSMemoryScheduler : public ComputationSchedulerAlgorithm {
   using ModuleSchedulerAlgorithm::Run;
   absl::StatusOr<HloInstructionSequence> Run(
       HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const HloAliasAnalysis& alias_analysis) const override;
 };
 
@@ -135,6 +143,7 @@ class BFScheduler : public ComputationSchedulerAlgorithm {
                                       std::move(postprocessor)) {}
   absl::StatusOr<HloInstructionSequence> Run(
       HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const HloAliasAnalysis& alias_analysis) const override;
 };
 
@@ -149,6 +158,7 @@ class PostOrderScheduler : public ComputationSchedulerAlgorithm {
   using ModuleSchedulerAlgorithm::Run;
   absl::StatusOr<HloInstructionSequence> Run(
       HloComputation* computation,
+      const TuplePointsToAnalysis& points_to_analysis,
       const HloAliasAnalysis& alias_analysis) const override;
 };
 
@@ -166,7 +176,8 @@ class DefaultMemoryScheduler : public ModuleSchedulerAlgorithm {
         dfs_scheduler_(alias_info, size_function, postprocessor),
         post_order_scheduler_(alias_info, size_function, postprocessor) {}
   absl::StatusOr<HloSchedule> Run(
-      const HloModule* module, const HloAliasAnalysis& alias_analysis,
+      const HloModule* module, const TuplePointsToAnalysis& points_to_analysis,
+      const HloAliasAnalysis& alias_analysis,
       const absl::flat_hash_set<absl::string_view>& execution_threads,
       int64_t* peak_memory) const override;