https://reviews.llvm.org/D111337

gistfile1.txt

diff --git a/flang/lib/Optimizer/Transforms/ArrayValueCopy.cpp b/flang/lib/Optimizer/Transforms/ArrayValueCopy.cpp
index 351a48a7d515..59f54e78c2a3 100644
--- a/flang/lib/Optimizer/Transforms/ArrayValueCopy.cpp
+++ b/flang/lib/Optimizer/Transforms/ArrayValueCopy.cpp
@@ -59,7 +59,7 @@ class ArrayCopyAnalysis {
 public:
   using ConflictSetT = llvm::SmallPtrSet<mlir::Operation *, 16>;
   using UseSetT = llvm::SmallPtrSet<mlir::OpOperand *, 8>;
-  using LoadMapSetsT = llvm::DenseMap<mlir::Operation *, UseSetT>;
+  using LoadMapSetsT = llvm::DenseMap<mlir::Operation *, SmallVector<Operation *>>;
 
   ArrayCopyAnalysis(mlir::Operation *op) : operation{op} {
     construct(op->getRegions());
@@ -79,15 +79,9 @@ public:
   /// back to the array load that is the original source of the array value.
   const OperationUseMapT &getUseMap() const { return useMap; }
 
-  /// For ArrayLoad `load`, return the transitive set of all OpOperands.
-  UseSetT getLoadUseSet(mlir::Operation *load) const {
-    assert(loadMapSets.count(load) && "analysis missed an array load?");
-    return loadMapSets.lookup(load);
-  }
-
   /// Get all the array value operations that use the original array value
   /// as passed to `store`.
-  void arrayAccesses(llvm::SmallVectorImpl<mlir::Operation *> &accesses,
+  const llvm::SmallVector<mlir::Operation *> &arrayAccesses(
                      ArrayLoadOp load);
 
 private:
@@ -269,19 +263,12 @@ private:
 
 /// Find all the array operations that access the array value that is loaded by
 /// the array load operation, `load`.
-void ArrayCopyAnalysis::arrayAccesses(
-    llvm::SmallVectorImpl<mlir::Operation *> &accesses, ArrayLoadOp load) {
-  accesses.clear();
+const llvm::SmallVector<mlir::Operation *> & ArrayCopyAnalysis::arrayAccesses(ArrayLoadOp load) {
   auto lmIter = loadMapSets.find(load);
   if (lmIter != loadMapSets.end()) {
-    for (auto *opnd : lmIter->second) {
-      auto *owner = opnd->getOwner();
-      if (mlir::isa<ArrayFetchOp, ArrayUpdateOp, ArrayModifyOp>(owner))
-        accesses.push_back(owner);
-    }
-    return;
+    return lmIter->getSecond();
   }
-
+  llvm::SmallVector<mlir::Operation *> accesses;
   UseSetT visited;
   llvm::SmallVector<mlir::OpOperand *> queue; // uses of ArrayLoad[orig]
 
@@ -357,7 +344,7 @@ void ArrayCopyAnalysis::arrayAccesses(
       llvm::report_fatal_error("array value reached unexpected op");
     }
   }
-  loadMapSets.insert({load, visited});
+  return loadMapSets.insert({load, accesses}).first->getSecond();
 }
 
 /// Is there a conflict between the array value that was updated and to be
@@ -443,8 +430,8 @@ void ArrayCopyAnalysis::construct(mlir::MutableArrayRef<mlir::Region> regions) {
         if (auto st = mlir::dyn_cast<fir::ArrayMergeStoreOp>(op)) {
           llvm::SmallVector<Operation *> values;
           ReachCollector::reachingValues(values, st.sequence());
-          llvm::SmallVector<Operation *> accesses;
-          arrayAccesses(accesses,
+          const llvm::SmallVector<Operation *> &accesses =
+          arrayAccesses(
                         mlir::cast<ArrayLoadOp>(st.original().getDefiningOp()));
           if (conflictDetected(values, accesses, st)) {
             LLVM_DEBUG(llvm::dbgs()
@@ -459,8 +446,8 @@ void ArrayCopyAnalysis::construct(mlir::MutableArrayRef<mlir::Region> regions) {
                      << "map: adding {" << *ld << " -> " << st << "}\n");
           useMap.insert({ld, &op});
         } else if (auto load = mlir::dyn_cast<ArrayLoadOp>(op)) {
-          llvm::SmallVector<mlir::Operation *> accesses;
-          arrayAccesses(accesses, load);
+          const llvm::SmallVector<mlir::Operation *> &accesses =
+          arrayAccesses(load);
           LLVM_DEBUG(llvm::dbgs() << "process load: " << load
                                   << ", accesses: " << accesses.size() << '\n');
           for (auto *acc : accesses) {