From 2c7c0bb01e83ee65d152571ae5cc19641c7bb995 Mon Sep 17 00:00:00 2001
From: Prithayan Barua <prithayan@gmail.com>
Date: Thu, 14 Mar 2024 09:15:42 -0700
Subject: [PATCH] Add a visited set

---
 lib/Dialect/FIRRTL/Transforms/InferReadWrite.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/Dialect/FIRRTL/Transforms/InferReadWrite.cpp b/lib/Dialect/FIRRTL/Transforms/InferReadWrite.cpp
index 14824b74c10a..470caddf8a5c 100644
--- a/lib/Dialect/FIRRTL/Transforms/InferReadWrite.cpp
+++ b/lib/Dialect/FIRRTL/Transforms/InferReadWrite.cpp
@@ -363,9 +363,12 @@ struct InferReadWritePass : public InferReadWriteBase<InferReadWritePass> {
       return defOp;
     };
     SmallVector<Value> stack;
+    llvm::SmallDenseSet<Value> visited;
     stack.push_back(wmodeDriver);
     while (!stack.empty()) {
       auto driver = stack.pop_back_val();
+      if (!visited.insert(driver).second)
+        continue;
       auto *defOp = getDriverOp(driver);
       if (!defOp)
         continue;