1 files changed, 24 insertions, 0 deletions
diff --git a/src/ir/iteration.h b/src/ir/iteration.h
index 289e5fa01..fd275f749 100644
--- a/src/ir/iteration.h
+++ b/src/ir/iteration.h
@@ -82,6 +82,30 @@ public:
   Iterator end() const { return Iterator(*this, children.size()); }
 };
 
+// Returns true if the current expression contains a certain kind of expression,
+// within the given depth of BFS. If depth is -1, this searches all children.
+template<typename T> bool containsChild(Expression* parent, int depth = -1) {
+  std::vector<Expression*> exprs;
+  std::vector<Expression*> nextExprs;
+  exprs.push_back(parent);
+  while (!exprs.empty() && depth > 0) {
+    for (auto* expr : exprs) {
+      for (auto* child : ChildIterator(expr)) {
+        if (child->is<T>()) {
+          return true;
+        }
+        nextExprs.push_back(child);
+      }
+    }
+    exprs.swap(nextExprs);
+    nextExprs.clear();
+    if (depth > 0) {
+      depth--;
+    }
+  }
+  return false;
+}
+
 } // namespace wasm
 
 #endif // wasm_ir_iteration_h