Trivial cleanup of iterateAndNext

src/V3Ast.cpp

@@ -958,15 +958,12 @@ void AstNode::iterateAndNext(VNVisitor& v) {
     // This is a very hot function
     // IMPORTANT: If you replace a node that's the target of this iterator,
     // then the NEW node will be iterated on next, it isn't skipped!
-    // Future versions of this function may require the node to have a back to be iterated;
-    // there's no lower level reason yet though the back must exist.
     AstNode* nodep = this;
 #ifdef VL_DEBUG  // Otherwise too hot of a function for debug
-    UASSERT_OBJ(!(nodep && !nodep->m_backp), nodep, "iterateAndNext node has no back");
+    UASSERT_OBJ(nodep->m_backp, nodep, "iterateAndNext node has no back");
 #endif
-    // cppcheck-suppress knownConditionTrueFalse
-    if (nodep) ASTNODE_PREFETCH(nodep->m_nextp);
-    while (nodep) {  // effectively: if (!this) return;  // Callers rely on this
+    ASTNODE_PREFETCH_NON_NULL(nodep->m_nextp);
+    do {
         if (nodep->m_nextp) ASTNODE_PREFETCH(nodep->m_nextp->m_nextp);
         AstNode* niterp = nodep;  // Pointer may get stomped via m_iterpp if the node is edited
         // Desirable check, but many places where multiple iterations are OK
@@ -986,7 +983,7 @@ void AstNode::iterateAndNext(VNVisitor& v) {
         } else {  // Unchanged node (though maybe updated m_next), just continue loop
             nodep = niterp->m_nextp;
         }
-    }
+    } while (nodep);
 }
 
 void AstNode::iterateListBackwardsConst(VNVisitorConst& v) {