Fix purity calculation during V3Const simplifying Ast

src/V3Ast.cpp

@@ -33,7 +33,7 @@ VL_DEFINE_DEBUG_FUNCTIONS;
 //======================================================================
 // Statics
 
-uint32_t VIsCached::s_cachedCntGbl = 1;
+uint64_t VIsCached::s_cachedCntGbl = 1;
 
 uint64_t AstNode::s_editCntLast = 0;
 uint64_t AstNode::s_editCntGbl = 0;  // Hot cache line

src/V3Ast.h

@@ -171,10 +171,9 @@ class VIsCached final {
     // Used in some nodes to cache results of boolean methods
     // If cachedCnt == 0, not cached
     // else if cachedCnt == s_cachedCntGbl, then m_state is if cached
-    uint32_t m_cachedCnt : 31;  // Mark of when cache was computed
+    uint64_t m_cachedCnt : 63;  // Mark of when cache was computed
-    uint32_t m_state : 1;
+    uint64_t m_state : 1;
-    static uint32_t s_cachedCntGbl;  // Global computed count
+    static uint64_t s_cachedCntGbl;  // Global computed count
-    static constexpr uint32_t MAX_CNT = (1UL << 31) - 1;  // Max for m_cachedCnt
 
 public:
     VIsCached()
@@ -192,7 +191,8 @@ public:
     }
     static void clearCacheTree() {
         ++s_cachedCntGbl;
-        UASSERT_STATIC(s_cachedCntGbl < MAX_CNT, "Overflow of cache counting");
+        // 64 bits so won't overflow
+        // UASSERT_STATIC(s_cachedCntGbl < MAX_CNT, "Overflow of cache counting");
     }
 };
 
@@ -1956,6 +1956,7 @@ public:
     uint64_t editCount() const { return m_editCount; }
     void editCountInc() {
         m_editCount = ++s_editCntGbl;  // Preincrement, so can "watch AstNode::s_editCntGbl=##"
+        VIsCached::clearCacheTree();  // Any edit clears all caching
     }
 #else
     void editCountInc() { ++s_editCntGbl; }

src/V3AstNodeExpr.h

@@ -64,7 +64,6 @@ public:
 
     // Wrap This expression into an AstStmtExpr to denote it occurs in statement position
     inline AstStmtExpr* makeStmt();
-    virtual void clearCachedPurity(){};  // Most nodes don't cache their purity
 };
 class AstNodeBiop VL_NOT_FINAL : public AstNodeExpr {
     // Binary expression
@@ -98,7 +97,6 @@ public:
     bool same(const AstNode*) const override { return true; }
     bool isPure() override;
     const char* broken() const override;
-    void clearCachedPurity() override;
 
 private:
     bool getPurityRecurse() const { return lhsp()->isPure() && rhsp()->isPure(); }
@@ -265,7 +263,6 @@ public:
     string emitVerilog() final override { V3ERROR_NA_RETURN(""); }
     string emitC() final override { V3ERROR_NA_RETURN(""); }
     bool cleanOut() const final override { V3ERROR_NA_RETURN(true); }
-    void clearCachedPurity() override;
 
 private:
     bool getPurityRecurse() const;
@@ -296,7 +293,6 @@ public:
     bool cleanOut() const final override { V3ERROR_NA_RETURN(true); }
     bool isPure() override;
     const char* broken() const override;
-    void clearCachedPurity() override;
 
 private:
     bool getPurityRecurse() const {
@@ -340,7 +336,6 @@ public:
     bool same(const AstNode*) const override { return true; }
     bool isPure() override;
     const char* broken() const override;
-    void clearCachedPurity() override;
 
 private:
     bool getPurityRecurse() const {
@@ -393,7 +388,6 @@ public:
     bool same(const AstNode*) const override { return true; }
     bool isPure() override;
     const char* broken() const override;
-    void clearCachedPurity() override;
 
 private:
     bool getPurityRecurse() const {
@@ -473,7 +467,6 @@ public:
     bool same(const AstNode*) const override { return true; }
     bool isPure() override;
     const char* broken() const override;
-    void clearCachedPurity() override;
 };
 class AstNodeSystemUniopD VL_NOT_FINAL : public AstNodeUniop {
 public:

src/V3AstNodes.cpp

@@ -72,11 +72,6 @@ bool AstNodeFTaskRef::isPure() {
     }
 }
 
-void AstNodeFTaskRef::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
-
 bool AstNodeFTaskRef::getPurityRecurse() const {
     AstNodeFTask* const taskp = this->taskp();
     // Unlinked yet, so treat as impure
@@ -152,11 +147,6 @@ const char* AstNodeUniop::broken() const {
     BROKEN_RTN(m_purity.isCached() && m_purity.get() != lhsp()->isPure());
     return nullptr;
 }
-void AstNodeUniop::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
-
 bool AstNodeBiop::isPure() {
     if (!m_purity.isCached()) m_purity.set(getPurityRecurse());
     return m_purity.get();
@@ -165,10 +155,6 @@ const char* AstNodeBiop::broken() const {
     BROKEN_RTN(m_purity.isCached() && m_purity.get() != getPurityRecurse());
     return nullptr;
 }
-void AstNodeBiop::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
 
 bool AstNodeTriop::isPure() {
     if (!m_purity.isCached()) m_purity.set(getPurityRecurse());
@@ -178,10 +164,6 @@ const char* AstNodeTriop::broken() const {
     BROKEN_RTN(m_purity.isCached() && m_purity.get() != getPurityRecurse());
     return nullptr;
 }
-void AstNodeTriop::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
 
 bool AstNodePreSel::isPure() {
     if (!m_purity.isCached()) m_purity.set(getPurityRecurse());
@@ -191,10 +173,6 @@ const char* AstNodePreSel::broken() const {
     BROKEN_RTN(m_purity.isCached() && m_purity.get() != getPurityRecurse());
     return nullptr;
 }
-void AstNodePreSel::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
 
 bool AstNodeQuadop::isPure() {
     if (!m_purity.isCached()) m_purity.set(getPurityRecurse());
@@ -204,10 +182,6 @@ const char* AstNodeQuadop::broken() const {
     BROKEN_RTN(m_purity.isCached() && m_purity.get() != getPurityRecurse());
     return nullptr;
 }
-void AstNodeQuadop::clearCachedPurity() {
-    m_purity.clearCache();
-    if (AstNodeExpr* const exprp = VN_CAST(backp(), NodeExpr)) exprp->clearCachedPurity();
-}
 
 AstNodeCond::AstNodeCond(VNType t, FileLine* fl, AstNodeExpr* condp, AstNodeExpr* thenp,
                          AstNodeExpr* elsep)

src/V3Inline.cpp

@@ -174,7 +174,7 @@ private:
         // MethodCalls not currently supported by inliner, so keep linked
         if (!nodep->classOrPackagep() && !VN_IS(nodep, MethodCall)) {
             nodep->taskp(nullptr);
-            nodep->clearCachedPurity();
+            VIsCached::clearCacheTree();
         }
         iterateChildren(nodep);
     }

src/V3LinkDot.cpp

@@ -3726,6 +3726,7 @@ public:
 // Link class functions
 
 void V3LinkDot::linkDotGuts(AstNetlist* rootp, VLinkDotStep step) {
+    VIsCached::clearCacheTree();  // Avoid using any stale isPure
     if (debug() >= 5 || dumpTreeLevel() >= 9) {
         v3Global.rootp()->dumpTreeFile(v3Global.debugFilename("prelinkdot.tree"));
     }

src/V3Premit.cpp

@@ -331,7 +331,7 @@ private:
             // We're going to need the expression several times in the expanded code,
             // so might as well make it a common expression
             createDeepTemp(nodep->condp(), false);
-            nodep->clearCachedPurity();
+            VIsCached::clearCacheTree();
         }
         checkNode(nodep);
     }

src/V3Scope.cpp

@@ -396,7 +396,7 @@ private:
             UINFO(9, "   New pkg-taskref " << nodep << endl);
         } else if (!VN_IS(nodep, MethodCall)) {
             nodep->taskp(nullptr);
-            nodep->clearCachedPurity();
+            VIsCached::clearCacheTree();
             UINFO(9, "   New pkg-taskref " << nodep << endl);
         }
         iterateChildren(nodep);

src/V3Task.cpp

@@ -1469,9 +1469,9 @@ private:
             beginp = new AstExprStmt{nodep->fileline(), beginp, outrefp};
             // AstExprStmt is currently treated as impure, so clear the cached purity of its
             // parents
-            nodep->clearCachedPurity();
             nodep->replaceWith(beginp);
             VL_DO_DANGLING(nodep->deleteTree(), nodep);
+            VIsCached::clearCacheTree();
         } else {
             insertBeforeStmt(nodep, beginp);
             if (nodep->taskp()->isFunction()) {