From ae466b170361af49beac5c827638fbec9a3ab6e2 Mon Sep 17 00:00:00 2001
From: Kamil Rakoczy <krakoczy@antmicro.com>
Date: Wed, 14 Sep 2022 13:37:51 +0200
Subject: [PATCH] Internals: Improve Verilation peak memory usage in V3Subst
 (#3512).

---
 src/V3Subst.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/V3Subst.cpp b/src/V3Subst.cpp
index ef7562ac5..ce43a7fd0 100644
--- a/src/V3Subst.cpp
+++ b/src/V3Subst.cpp
@@ -359,6 +359,13 @@ private:
     }
     virtual void visit(AstVar*) override {}
     virtual void visit(AstConst*) override {}
+    virtual void visit(AstModule* nodep) override {
+        ++m_ops;
+        if (!nodep->isSubstOptimizable()) m_ops = SUBST_MAX_OPS_NA;
+        iterateChildren(nodep);
+        // Reduce peak memory usage by reclaiming the edited AstNodes
+        doDeletes();
+    }
     virtual void visit(AstNode* nodep) override {
         m_ops++;
         if (!nodep->isSubstOptimizable()) m_ops = SUBST_MAX_OPS_NA;