[clang][dataflow] Fix MapLattice::insert() to not drop return value

Fix `MapLattice` API to return `std::pair<iterator, bool>`,
allowing users to detect when an element has been inserted without
performing a redundant map lookup.

Differential Revision: https://reviews.llvm.org/D130497

1 files changed, 6 insertions, 3 deletions

diff --git a/clang/include/clang/Analysis/FlowSensitive/MapLattice.h b/clang/include/clang/Analysis/FlowSensitive/MapLattice.h
index 014cd60..16b0c978 100644
--- a/clang/include/clang/Analysis/FlowSensitive/MapLattice.h
+++ b/clang/include/clang/Analysis/FlowSensitive/MapLattice.h
@@ -54,10 +54,13 @@ public:
   // The `bottom` element is the empty map.
   static MapLattice bottom() { return MapLattice(); }
 
-  void insert(const std::pair<const key_type, mapped_type> &P) { C.insert(P); }
+  std::pair<iterator, bool>
+  insert(const std::pair<const key_type, mapped_type> &P) {
+    return C.insert(P);
+  }
 
-  void insert(std::pair<const key_type, mapped_type> &&P) {
-    C.insert(std::move(P));
+  std::pair<iterator, bool> insert(std::pair<const key_type, mapped_type> &&P) {
+    return C.insert(std::move(P));
   }
 
   unsigned size() const { return C.size(); }