1 files changed, 8 insertions, 4 deletions
diff --git a/src/expr.c b/src/expr.c
index bda91df83..b7dbc721e 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4270,10 +4270,14 @@ void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
 void sqlite3ExprToRegister(Expr *pExpr, int iReg){
   Expr *p = sqlite3ExprSkipCollateAndLikely(pExpr);
   if( NEVER(p==0) ) return;
-  p->op2 = p->op;
-  p->op = TK_REGISTER;
-  p->iTable = iReg;
-  ExprClearProperty(p, EP_Skip);
+  if( p->op==TK_REGISTER ){
+    assert( p->iTable==iReg );
+  }else{
+    p->op2 = p->op;
+    p->op = TK_REGISTER;
+    p->iTable = iReg;
+    ExprClearProperty(p, EP_Skip);
+  }
 }
 
 /*