Ensure DFG stats are consistent

src/V3DfgAstToDfg.cpp

@@ -85,6 +85,7 @@ class AstToDfgVisitor final : public VNVisitor {
     V3DfgOptimizationContext& m_ctx;  // The optimization context for stats
     bool m_foundUnhandled = false;  // Found node not implemented as DFG or not implemented 'visit'
     std::vector<DfgVertex*> m_uncommittedVertices;  // Vertices that we might decide to revert
+    bool m_converting = false;  // We are trying to convert some logic at the moment
 
     // METHODS
     void markReferenced(AstNode* nodep) {
@@ -141,8 +142,8 @@ class AstToDfgVisitor final : public VNVisitor {
     // VISITORS
     void visit(AstNode* nodep) override {
         // Conservatively treat this node as unhandled
+        if (!m_foundUnhandled && m_converting) ++m_ctx.m_nonRepUnknown;
         m_foundUnhandled = true;
-        ++m_ctx.m_nonRepUnknown;
         markReferenced(nodep);
     }
     void visit(AstCell* nodep) override { markReferenced(nodep); }
@@ -158,6 +159,10 @@ class AstToDfgVisitor final : public VNVisitor {
     }
 
     void visit(AstAssignW* nodep) override {
+        VL_RESTORER(m_converting);
+        m_converting = true;
+        ++m_ctx.m_inputEquations;
+
         // Cannot handle assignment with timing control yet
         if (nodep->timingControlp()) {
             markReferenced(nodep);

src/V3DfgPasses.cpp

@@ -53,6 +53,7 @@ V3DfgOptimizationContext::V3DfgOptimizationContext(const std::string& label)
 V3DfgOptimizationContext::~V3DfgOptimizationContext() {
     const string prefix = "Optimizations, DFG " + m_label + " ";
     V3Stats::addStat(prefix + "General, modules", m_modules);
+    V3Stats::addStat(prefix + "Ast2Dfg, input equations", m_inputEquations);
     V3Stats::addStat(prefix + "Ast2Dfg, representable", m_representable);
     V3Stats::addStat(prefix + "Ast2Dfg, non-representable (dtype)", m_nonRepDType);
     V3Stats::addStat(prefix + "Ast2Dfg, non-representable (impure)", m_nonRepImpure);
@@ -65,6 +66,12 @@ V3DfgOptimizationContext::~V3DfgOptimizationContext() {
     V3Stats::addStat(prefix + "Dfg2Ast, intermediate variables", m_intermediateVars);
     V3Stats::addStat(prefix + "Dfg2Ast, replaced variables", m_replacedVars);
     V3Stats::addStat(prefix + "Dfg2Ast, result equations", m_resultEquations);
+
+    // Check the stats are consistent
+    UASSERT(m_inputEquations
+                == m_representable + m_nonRepDType + m_nonRepImpure + m_nonRepTiming + m_nonRepLhs
+                       + m_nonRepNode + m_nonRepUnknown + m_nonRepVarRef + m_nonRepWidth,
+            "Inconsistent statistics");
 }
 
 // 'Inline' DfgVar nodes with known drivers

src/V3DfgPasses.h

@@ -54,6 +54,7 @@ class V3DfgOptimizationContext final {
 
 public:
     VDouble0 m_modules;  // Number of modules optimized
+    VDouble0 m_inputEquations;  // Number of input combinational equations
     VDouble0 m_representable;  // Number of combinational equations representable
     VDouble0 m_nonRepDType;  // Equations non-representable due to data type
     VDouble0 m_nonRepImpure;  // Equations non-representable due to impure node