[MLIR][RemoveDeadValues] Privatize public function beforehand.

Author: navyxliu

mlir/include/mlir/Analysis/DataFlow/LivenessAnalysis.h

@@ -24,6 +24,7 @@
 #define MLIR_ANALYSIS_DATAFLOW_LIVENESSANALYSIS_H
 
 #include <mlir/Analysis/DataFlow/SparseAnalysis.h>
+#include <mlir/Pass/AnalysisManager.h>
 #include <optional>
 
 namespace mlir::dataflow {
@@ -101,13 +102,17 @@ struct RunLivenessAnalysis {
   RunLivenessAnalysis(Operation *op);
 
   const Liveness *getLiveness(Value val);
-
+  // This only mark Liveness results are stale.
+  void invalidate() { valid = false; }
   /// Return the configuration of the solver used for this analysis.
   const DataFlowConfig &getSolverConfig() const { return solver.getConfig(); }
+  /// The function is called by analysis_impl::isInvalidated.
+  bool isInvalidated(AnalysisManager::PreservedAnalyses&) const { return !valid; }
 
 private:
   /// Stores the result of the liveness analysis that was run.
   DataFlowSolver solver;
+  bool valid {true};
 };
 
 } // end namespace mlir::dataflow

mlir/include/mlir/IR/Visitors.h

@@ -39,20 +39,6 @@ struct ForwardIterator {
   }
 };
 
-/// This iterator enumerates the elements in "backward" order.
-struct BackwardIterator {
-  template <typename T>
-  static auto makeIterable(T &range) {
-    if constexpr (std::is_same<T, Operation>()) {
-      /// Make operations iterable: return the list of regions.
-      return range.getRegions();
-    } else {
-      /// Regions and block are already iterable.
-      return llvm::reverse(range);
-    }
-  }
-};
-
 /// A utility class to encode the current walk stage for "generic" walkers.
 /// When walking an operation, we can either choose a Pre/Post order walker
 /// which invokes the callback on an operation before/after all its attached

mlir/lib/Analysis/DataFlow/LivenessAnalysis.cpp

@@ -325,5 +325,6 @@ RunLivenessAnalysis::RunLivenessAnalysis(Operation *op) {
 }
 
 const Liveness *RunLivenessAnalysis::getLiveness(Value val) {
+  assert(valid && "getLiveness called after invalidate");
   return solver.lookupState<Liveness>(val);
 }