From 8bffb8c39149bc908d9ef079ab19ea7b4163ecde Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 2 Jul 2024 09:22:32 -0400
Subject: [PATCH] Fix table optimizing logic with side effect (#5137 prep)

---
 src/V3Simulate.h |  8 ++++----
 src/V3Table.cpp  | 10 ++++------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/V3Simulate.h b/src/V3Simulate.h
index 559d30613..c491f9905 100644
--- a/src/V3Simulate.h
+++ b/src/V3Simulate.h
@@ -107,7 +107,7 @@ private:
     bool m_anyAssignDly;  ///< True if found a delayed assignment
     bool m_anyAssignComb;  ///< True if found a non-delayed assignment
     bool m_inDlyAssign;  ///< Under delayed assignment
-    bool m_isOutputter;  // Creates output
+    bool m_isImpure;  // Not pure
     int m_instrCount;  ///< Number of nodes
     int m_dataCount;  ///< Bytes of data
     AstJumpGo* m_jumpp = nullptr;  ///< Jump label we're branching from
@@ -214,7 +214,7 @@ public:
     AstNode* whyNotNodep() const { return m_whyNotNodep; }
 
     bool isAssignDly() const { return m_anyAssignDly; }
-    bool isOutputter() const { return m_isOutputter; }
+    bool isImpure() const { return m_isImpure; }
     int instrCount() const { return m_instrCount; }
     int dataCount() const { return m_dataCount; }
 
@@ -359,7 +359,7 @@ private:
             // UINFO(9, "     !predictopt " << nodep << endl);
             clearOptimizable(nodep, "Isn't predictable");
         }
-        if (nodep->isOutputter()) m_isOutputter = true;
+        if (!nodep->isPure()) m_isImpure = true;
     }
 
     void knownBadNodeType(AstNode* nodep) {
@@ -1231,7 +1231,7 @@ public:
         m_anyAssignComb = false;
         m_anyAssignDly = false;
         m_inDlyAssign = false;
-        m_isOutputter = false;
+        m_isImpure = false;
         m_instrCount = 0;
         m_dataCount = 0;
         m_jumpp = nullptr;
diff --git a/src/V3Table.cpp b/src/V3Table.cpp
index cbba13680..a7bddd93e 100644
--- a/src/V3Table.cpp
+++ b/src/V3Table.cpp
@@ -209,6 +209,10 @@ private:
         // Instruction count bytes (ok, it's space also not time :)
         const double time  // max(_, 1), so we won't divide by zero
             = std::max<double>(chkvis.instrCount() * TABLE_BYTES_PER_INST + chkvis.dataCount(), 1);
+        if (chkvis.isImpure()) chkvis.clearOptimizable(nodep, "Table creates side effects");
+        if (!m_outWidthBytes || !m_inWidthBits) {
+            chkvis.clearOptimizable(nodep, "Table has no outputs");
+        }
         if (chkvis.instrCount() < TABLE_MIN_NODE_COUNT) {
             chkvis.clearOptimizable(nodep, "Table has too few nodes involved");
         }
@@ -221,12 +225,6 @@ private:
         if (m_totalBytes > TABLE_TOTAL_BYTES) {
             chkvis.clearOptimizable(nodep, "Table out of memory");
         }
-        if (!m_outWidthBytes || !m_inWidthBits) {
-            chkvis.clearOptimizable(nodep, "Table has no outputs");
-        }
-        if (chkvis.isOutputter()) {
-            chkvis.clearOptimizable(nodep, "Table creates display output");
-        }
         UINFO(4, "  Test: Opt=" << (chkvis.optimizable() ? "OK" : "NO") << ", Instrs="
                                 << chkvis.instrCount() << " Data=" << chkvis.dataCount()
                                 << " in width (bits)=" << m_inWidthBits << " out width (bytes)="