1 files changed, 40 insertions, 6 deletions

diff --git a/src/expr.c b/src/expr.c
index b39dea2ea..6371e15ca 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -548,11 +548,11 @@ Expr *sqlite3PExpr(
   const Token *pToken     /* Argument token */
 ){
   Expr *p;
-  if( op==TK_AND && pLeft && pRight && pParse->nErr==0 ){
+  if( op==TK_AND && pParse->nErr==0 ){
     /* Take advantage of short-circuit false optimization for AND */
     p = sqlite3ExprAnd(pParse->db, pLeft, pRight);
   }else{
-    p = sqlite3ExprAlloc(pParse->db, op, pToken, 1);
+    p = sqlite3ExprAlloc(pParse->db, op & TKFLG_MASK, pToken, 1);
     sqlite3ExprAttachSubtrees(pParse->db, p, pLeft, pRight);
   }
   if( p ) {
@@ -1415,6 +1415,22 @@ int sqlite3ExprIsConstantOrFunction(Expr *p, u8 isInit){
   return exprIsConst(p, 4+isInit, 0);
 }
 
+#ifdef SQLITE_ENABLE_CURSOR_HINTS
+/*
+** Walk an expression tree.  Return 1 if the expression contains a
+** subquery of some kind.  Return 0 if there are no subqueries.
+*/
+int sqlite3ExprContainsSubquery(Expr *p){
+  Walker w;
+  memset(&w, 0, sizeof(w));
+  w.eCode = 1;
+  w.xExprCallback = sqlite3ExprWalkNoop;
+  w.xSelectCallback = selectNodeIsConstant;
+  sqlite3WalkExpr(&w, p);
+  return w.eCode==0;
+}
+#endif
+
 /*
 ** If the expression p codes a constant integer that is small enough
 ** to fit in a 32-bit integer, return 1 and put the value of the integer
@@ -2481,9 +2497,12 @@ void sqlite3ExprCodeGetColumnOfTable(
 
 /*
 ** Generate code that will extract the iColumn-th column from
-** table pTab and store the column value in a register.  An effort
-** is made to store the column value in register iReg, but this is
-** not guaranteed.  The location of the column value is returned.
+** table pTab and store the column value in a register. 
+**
+** An effort is made to store the column value in register iReg.  This
+** is not garanteeed for GetColumn() - the result can be stored in
+** any register.  But the result is guaranteed to land in register iReg
+** for GetColumnToReg().
 **
 ** There must be an open cursor to pTab in iTable when this routine
 ** is called.  If iColumn<0 then code is generated that extracts the rowid.
@@ -2494,7 +2513,7 @@ int sqlite3ExprCodeGetColumn(
   int iColumn,     /* Index of the table column */
   int iTable,      /* The cursor pointing to the table */
   int iReg,        /* Store results here */
-  u8 p5            /* P5 value for OP_Column */
+  u8 p5            /* P5 value for OP_Column + FLAGS */
 ){
   Vdbe *v = pParse->pVdbe;
   int i;
@@ -2516,6 +2535,17 @@ int sqlite3ExprCodeGetColumn(
   }
   return iReg;
 }
+void sqlite3ExprCodeGetColumnToReg(
+  Parse *pParse,   /* Parsing and code generating context */
+  Table *pTab,     /* Description of the table we are reading from */
+  int iColumn,     /* Index of the table column */
+  int iTable,      /* The cursor pointing to the table */
+  int iReg         /* Store results here */
+){
+  int r1 = sqlite3ExprCodeGetColumn(pParse, pTab, iColumn, iTable, iReg, 0);
+  if( r1!=iReg ) sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, r1, iReg);
+}
+
 
 /*
 ** Clear all column cache entries.
@@ -3342,6 +3372,10 @@ void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
 **
 ** The SQLITE_ECEL_FACTOR argument allows constant arguments to be
 ** factored out into initialization code.
+**
+** The SQLITE_ECEL_REF flag means that expressions in the list with
+** ExprList.a[].u.x.iOrderByCol>0 have already been evaluated and stored
+** in registers at srcReg, and so the value can be copied from there.
 */
 int sqlite3ExprCodeExprList(
   Parse *pParse,     /* Parsing context */