[flang] [llvm] [mlir] [MLIR][OpenMP] Introduce overlapped record type map support (PR #119588)

[Jan Leyonberg via llvm-commits]

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@@ -4129,6 +4154,87 @@ calculateBoundsOffset(LLVM::ModuleTranslation &moduleTranslation,
   return idx;
 }
 
+static void getAsIntegers(ArrayAttr values, llvm::SmallVector<int64_t> &ints) {
+  llvm::transform(values, std::back_inserter(ints), [](Attribute value) {
+    return cast<IntegerAttr>(value).getInt();
+  });
+};
+
+// Gathers members that are overlapping in the parent, excluding members that
+// themselves overlap, keeping the top-most (closest to parents level) map.
+static void
+getOverlappedMembers(llvm::SmallVectorImpl<size_t> &overlapMapDataIdxs,
+                     MapInfoData &mapData, omp::MapInfoOp parentOp) {
+  // No members mapped, no overlaps.
+  if (parentOp.getMembers().empty())
+    return;
+
+  // Single member, we can insert and return early.
+  if (parentOp.getMembers().size() == 1) {
+    overlapMapDataIdxs.push_back(0);
+    return;
+  }
+
+  // 1) collect list of top-level overlapping members from MemberOp
+  llvm::SmallVector<std::pair<int, ArrayAttr>> memberByIndex;
+  ArrayAttr indexAttr = parentOp.getMembersIndexAttr();
+  for (auto [memIndex, indicesAttr] : llvm::enumerate(indexAttr))
+    memberByIndex.push_back(
+        std::make_pair(memIndex, cast<ArrayAttr>(indicesAttr)));
+
+  // Sort the smallest first (higher up the parent -> member chain), so that
+  // when we remove members, we remove as much as we can in the initial
+  // iterations, shortening the number of passes required.
+  llvm::sort(memberByIndex.begin(), memberByIndex.end(),
+             [&](auto a, auto b) { return a.second.size() < b.second.size(); });
+
+  // Remove elements from the vector if there is a parent element that
+  // supersedes it. i.e. if member [0] is mapped, we can remove members [0,1],
+  // [0,2].. etc.
+  llvm::SmallVector<std::pair<int, ArrayAttr>> skipList;
+  for (auto v : memberByIndex) {
+    llvm::SmallVector<int64_t> vArr(v.second.size());
+    getAsIntegers(v.second, vArr);
+    skipList.push_back(
+        *std::find_if(memberByIndex.begin(), memberByIndex.end(), [&](auto x) {
+          if (v == x)
+            return false;
+          llvm::SmallVector<int64_t> xArr(x.second.size());
+          getAsIntegers(x.second, xArr);
+          return std::equal(vArr.begin(), vArr.end(), xArr.begin()) &&
+                 xArr.size() >= vArr.size();
+        }));
+  }
+
+  // Collect the indices from mapData that we need, as we technically need the
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jsjodin wrote:

Stale comment

https://github.com/llvm/llvm-project/pull/119588