From 2ac7cf51a9d96df6876c17e0d3a364ded5bd0e1a Mon Sep 17 00:00:00 2001
From: Igor Zaworski <izaworski@internships.antmicro.com>
Date: Fri, 10 Oct 2025 16:05:47 +0200
Subject: [PATCH] Optimization of typedef params (#6543) (#6547)

---
 src/V3Param.cpp | 27 ++++++++++++++++-----------
 src/V3Width.cpp |  9 ---------
 src/V3Width.h   |  3 ---
 3 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/src/V3Param.cpp b/src/V3Param.cpp
index 3127601e6..665c0f4e7 100644
--- a/src/V3Param.cpp
+++ b/src/V3Param.cpp
@@ -1277,12 +1277,12 @@ class ParamVisitor final : public VNVisitor {
     string m_unlinkedTxt;  // Text for AstUnlinkedRef
     std::multimap<bool, AstNode*> m_cellps;  // Cells left to process (in current module)
     std::deque<std::string> m_strings;  // Allocator for temporary strings
+    std::map<const AstRefDType*, bool>
+        m_isCircular;  // Stores information whether `AstRefDType` is circular
 
     // STATE - for current visit position (use VL_RESTORER)
     AstNodeModule* m_modp;  // Module iterating
     string m_generateHierName;  // Generate portion of hierarchy name
-    std::map<const AstRefDType*, bool>
-        m_isCircularTypeCache;  // Caches return values of `V3Width::isCircularType` calls
 
     // METHODS
 
@@ -1417,16 +1417,21 @@ class ParamVisitor final : public VNVisitor {
             processWorkQ();
         }
     }
-    void visit(AstRefDType* nodep) override {
-        const auto iter = m_isCircularTypeCache.find(nodep);
-        bool isCircular;
-        if (iter != m_isCircularTypeCache.end()) {
-            isCircular = iter->second;
-        } else {
-            isCircular = V3Width::isCircularType(nodep);
-            m_isCircularTypeCache.emplace(nodep, isCircular);
+
+    bool isCircularType(const AstRefDType* nodep) {
+        const auto iter = m_isCircular.emplace(nodep, true);
+        if (!iter.second) return iter.first->second;
+        if (const AstRefDType* const subDTypep = VN_CAST(nodep->subDTypep(), RefDType)) {
+            const bool ret = isCircularType(subDTypep);
+            iter.first->second = ret;
+            return ret;
         }
-        if (isCircular) {
+        iter.first->second = false;
+        return false;
+    }
+
+    void visit(AstRefDType* nodep) override {
+        if (isCircularType(nodep)) {
             nodep->v3error("Typedef's type is circular: " << nodep->prettyName());
         } else if (nodep->typedefp() && nodep->subDTypep()
                    && (VN_IS(nodep->subDTypep()->skipRefOrNullp(), IfaceRefDType)
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 99336502d..eafd432dc 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -8952,12 +8952,3 @@ AstNode* V3Width::widthGenerateParamsEdit(
     // No WidthRemoveVisitor, as don't want to drop $signed etc inside gen blocks
     return nodep;
 }
-
-bool V3Width::isCircularType(const AstRefDType* nodep) {
-    std::set<const AstRefDType*> visited;
-    while (nodep) {
-        if (!visited.insert(nodep).second) return true;
-        nodep = VN_CAST(nodep->subDTypep(), RefDType);
-    }
-    return false;
-}
diff --git a/src/V3Width.h b/src/V3Width.h
index b4a977941..88eb86c2a 100644
--- a/src/V3Width.h
+++ b/src/V3Width.h
@@ -23,7 +23,6 @@
 class AstNetlist;
 class AstNode;
 class AstNodeDType;
-class AstRefDType;
 
 //============================================================================
 
@@ -37,8 +36,6 @@ public:
     // Replace AstSelBit, etc with AstSel/AstArraySel
     // Returns replacement node if nodep was deleted, or null if none.
     static AstNode* widthSelNoIterEdit(AstNode* nodep) VL_MT_DISABLED;
-
-    static bool isCircularType(const AstRefDType* nodep);
 };
 
 #endif  // Guard