Add --autoflush option

src/V3Premit.cpp

@@ -23,6 +23,9 @@
 //	For each wide OP, make a a temporary variable with the wide value
 //	For each deep expression, assign expression to temporary.
 //
+// Each display (independant transformation; here as Premit is a good point)
+//	If autoflush, insert a flush
+//
 //*************************************************************************
 
 #include "config_build.h"
@@ -264,6 +267,26 @@ private:
 	checkNode(nodep);
     }
 
+    // Autoflush
+    virtual void visit(AstDisplay* nodep, AstNUser* vup) {
+	startStatement(nodep);
+	nodep->iterateChildren(*this);
+	m_stmtp = NULL;
+	if (v3Global.opt.autoflush()) {
+	    AstNode* searchp = nodep->nextp();
+	    while (searchp && searchp->castComment()) searchp = searchp->nextp();
+	    if (searchp
+		&& searchp->castDisplay()
+		&& nodep->filep()->sameTree(searchp->castDisplay()->filep())) {
+		// There's another display next; we can just wait to flush
+	    } else {
+		UINFO(4,"Autoflush "<<nodep<<endl);
+		nodep->addNextHere(new AstFFlush(nodep->fileline(),
+						 nodep->filep()->cloneTree(true)));
+	    }
+	}
+    }
+
     //--------------------
     // Default: Just iterate
     virtual void visit(AstVar* nodep, AstNUser*) {}	// Don't hit varrefs under vars