Index: src/walker.c
==================================================================
--- src/walker.c
+++ src/walker.c
@@ -34,13 +34,12 @@
 **                      return the top-level walk call.
 **
 ** The return value from this routine is WRC_Abort to abandon the tree walk
 ** and WRC_Continue to continue.
 */
-int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
+static SQLITE_NOINLINE int walkExpr(Walker *pWalker, Expr *pExpr){
   int rc;
-  if( pExpr==0 ) return WRC_Continue;
   testcase( ExprHasProperty(pExpr, EP_TokenOnly) );
   testcase( ExprHasProperty(pExpr, EP_Reduced) );
   rc = pWalker->xExprCallback(pWalker, pExpr);
   if( rc==WRC_Continue
               && !ExprHasProperty(pExpr,EP_TokenOnly) ){
@@ -52,10 +51,13 @@
       if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
     }
   }
   return rc & WRC_Abort;
 }
+int sqlite3WalkExpr(Walker *pWalker, Expr *pExpr){
+  return pExpr ? walkExpr(pWalker,pExpr) : WRC_Continue;
+}
 
 /*
 ** Call sqlite3WalkExpr() for every expression in list p or until
 ** an abort request is seen.
 */