[llvm-branch-commits] [OpenMP][MLIR] Extend explicit derived type member mapping support for OpenMP dialects lowering to LLVM-IR (PR #81510)

[Kareem Ergawy via llvm-branch-commits]

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@@ -1783,6 +1783,98 @@ void collectMapDataFromMapOperands(MapInfoData &mapData,
   }
 }
 
+static int getMapDataMemberIdx(MapInfoData &mapData,
+                               mlir::omp::MapInfoOp memberOp) {
+  int memberDataIdx = -1;
+  for (size_t i = 0; i < mapData.MapClause.size(); ++i) {
+    if (mapData.MapClause[i] == memberOp)
+      memberDataIdx = i;
+  }
+  return memberDataIdx;
+}
+
+static mlir::omp::MapInfoOp
+getFirstOrLastMappedMemberPtr(mlir::omp::MapInfoOp mapInfo, bool first) {
+  // Only 1 member has been mapped, we can return it.
+  if (mapInfo.getMembersIndex()->size() == 1)
+    if (auto mapOp = mlir::dyn_cast<mlir::omp::MapInfoOp>(
+            mapInfo.getMembers()[0].getDefiningOp()))
+      return mapOp;
+
+  int64_t curPos =
+      mapInfo.getMembersIndex()->begin()->cast<mlir::IntegerAttr>().getInt();
+
+  int64_t idx = 1, curIdx = 0, memberPlacement = 0;
+  for (const auto *iter = std::next(mapInfo.getMembersIndex()->begin());
+       iter != mapInfo.getMembersIndex()->end(); iter++) {
+    memberPlacement = iter->cast<mlir::IntegerAttr>().getInt();
+    if (first) {
+      if (memberPlacement < curPos) {
+        curIdx = idx;
+        curPos = memberPlacement;
+      }
+    } else {
+      if (memberPlacement > curPos) {
+        curIdx = idx;
+        curPos = memberPlacement;
+      }
+    }
+    idx++;
+  }
+
+  if (auto mapOp = mlir::dyn_cast<mlir::omp::MapInfoOp>(
+          mapInfo.getMembers()[curIdx].getDefiningOp()))
+    return mapOp;
+
+  return {};
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ergawy wrote:

Apologies for repeating this, but I think it is better to `assert` if some assumption in the code is violated rather than returning an empty value.

https://github.com/llvm/llvm-project/pull/81510