Merge latest trunk into this branch.

FossilOrigin-Name: eb13b8b3ef67ca8a252f7a4fd5a83ed31fefe68aa5ad8693d9d1f17218f4d176

1 files changed, 79 insertions, 20 deletions

diff --git a/src/expr.c b/src/expr.c
index cc915987d..37923bc84 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -2646,7 +2646,7 @@ static int sqlite3ExprIsTableConstant(Expr *p, int iCur, int bAllowSubq){
 **         (4a)  pExpr must come from an ON clause..
 **         (4b)  and specifically the ON clause associated with the LEFT JOIN.
 **
-**   (5)  If pSrc is not the right operand of a LEFT JOIN or the left
+**   (5)  If pSrc is the right operand of a LEFT JOIN or the left
 **        operand of a RIGHT JOIN, then pExpr must be from the WHERE
 **        clause, not an ON clause.
 **
@@ -6180,16 +6180,23 @@ void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
 ** same as that currently bound to variable pVar, non-zero is returned.
 ** Otherwise, if the values are not the same or if pExpr is not a simple
 ** SQL value, zero is returned.
+**
+** If the SQLITE_EnableQPSG flag is set on the database connection, then
+** this routine always returns false.
 */
-static int exprCompareVariable(
+static SQLITE_NOINLINE int exprCompareVariable(
   const Parse *pParse,
   const Expr *pVar,
   const Expr *pExpr
 ){
-  int res = 0;
+  int res = 2;
   int iVar;
   sqlite3_value *pL, *pR = 0;
  
+  if( pExpr->op==TK_VARIABLE && pVar->iColumn==pExpr->iColumn ){
+    return 0;
+  }
+  if( (pParse->db->flags & SQLITE_EnableQPSG)!=0 ) return 2;
   sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
   if( pR ){
     iVar = pVar->iColumn;
@@ -6199,12 +6206,11 @@ static int exprCompareVariable(
       if( sqlite3_value_type(pL)==SQLITE_TEXT ){
         sqlite3_value_text(pL); /* Make sure the encoding is UTF-8 */
       }
-      res =  0==sqlite3MemCompare(pL, pR, 0);
+      res = sqlite3MemCompare(pL, pR, 0) ? 2 : 0;
     }
     sqlite3ValueFree(pR);
     sqlite3ValueFree(pL);
   }
-
   return res;
 }
 
@@ -6230,12 +6236,10 @@ static int exprCompareVariable(
 ** just might result in some slightly slower code.  But returning
 ** an incorrect 0 or 1 could lead to a malfunction.
 **
-** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
-** pParse->pReprepare can be matched against literals in pB.  The
-** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
-** If pParse is NULL (the normal case) then any TK_VARIABLE term in
-** Argument pParse should normally be NULL. If it is not NULL and pA or
-** pB causes a return value of 2.
+** If pParse is not NULL and SQLITE_EnableQPSG is off then TK_VARIABLE
+** terms in pA with bindings in pParse->pReprepare can be matched against
+** literals in pB.  The pParse->pVdbe->expmask bitmask is updated for
+** each variable referenced.
 */
 int sqlite3ExprCompare(
   const Parse *pParse,
@@ -6247,8 +6251,8 @@ int sqlite3ExprCompare(
   if( pA==0 || pB==0 ){
     return pB==pA ? 0 : 2;
   }
-  if( pParse && pA->op==TK_VARIABLE && exprCompareVariable(pParse, pA, pB) ){
-    return 0;
+  if( pParse && pA->op==TK_VARIABLE ){
+    return exprCompareVariable(pParse, pA, pB);
   }
   combinedFlags = pA->flags | pB->flags;
   if( combinedFlags & EP_IntValue ){
@@ -6444,17 +6448,69 @@ static int exprImpliesNotNull(
 }
 
 /*
+** Return true if the boolean value of the expression is always either
+** FALSE or NULL.
+*/
+static int sqlite3ExprIsNotTrue(Expr *pExpr){
+  int v;
+  if( pExpr->op==TK_NULL ) return 1;
+  if( pExpr->op==TK_TRUEFALSE && sqlite3ExprTruthValue(pExpr)==0 ) return 1;
+  v = 1;
+  if( sqlite3ExprIsInteger(pExpr, &v, 0) && v==0 ) return 1;
+  return 0;
+}
+
+/*
+** Return true if the expression is one of the following:
+**
+**    CASE WHEN x THEN y END
+**    CASE WHEN x THEN y ELSE NULL END
+**    CASE WHEN x THEN y ELSE false END
+**    iif(x,y)
+**    iif(x,y,NULL)
+**    iif(x,y,false)
+*/
+static int sqlite3ExprIsIIF(sqlite3 *db, const Expr *pExpr){
+  ExprList *pList;
+  if( pExpr->op==TK_FUNCTION ){
+    const char *z = pExpr->u.zToken;
+    FuncDef *pDef;
+    if( (z[0]!='i' && z[0]!='I') ) return 0;
+    if( pExpr->x.pList==0 ) return 0;
+    pDef = sqlite3FindFunction(db, z, pExpr->x.pList->nExpr, ENC(db), 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+    if( pDef==0 ) return 0;
+#else
+    if( NEVER(pDef==0) ) return 0;
+#endif
+    if( (pDef->funcFlags & SQLITE_FUNC_INLINE)==0 ) return 0;
+    if( SQLITE_PTR_TO_INT(pDef->pUserData)!=INLINEFUNC_iif ) return 0;
+  }else if( pExpr->op==TK_CASE ){
+    if( pExpr->pLeft!=0 ) return 0;
+  }else{
+    return 0;
+  }
+  pList = pExpr->x.pList;
+  assert( pList!=0 );
+  if( pList->nExpr==2 ) return 1;
+  if( pList->nExpr==3 && sqlite3ExprIsNotTrue(pList->a[2].pExpr) ) return 1;
+  return 0;
+}
+
+/*
 ** Return true if we can prove the pE2 will always be true if pE1 is
 ** true.  Return false if we cannot complete the proof or if pE2 might
 ** be false.  Examples:
 **
-**     pE1: x==5       pE2: x==5             Result: true
-**     pE1: x>0        pE2: x==5             Result: false
-**     pE1: x=21       pE2: x=21 OR y=43     Result: true
-**     pE1: x!=123     pE2: x IS NOT NULL    Result: true
-**     pE1: x!=?1      pE2: x IS NOT NULL    Result: true
-**     pE1: x IS NULL  pE2: x IS NOT NULL    Result: false
-**     pE1: x IS ?2    pE2: x IS NOT NULL    Result: false
+**     pE1: x==5        pE2: x==5             Result: true
+**     pE1: x>0         pE2: x==5             Result: false
+**     pE1: x=21        pE2: x=21 OR y=43     Result: true
+**     pE1: x!=123      pE2: x IS NOT NULL    Result: true
+**     pE1: x!=?1       pE2: x IS NOT NULL    Result: true
+**     pE1: x IS NULL   pE2: x IS NOT NULL    Result: false
+**     pE1: x IS ?2     pE2: x IS NOT NULL    Result: false
+**     pE1: iif(x,y)    pE2: x                Result: true
+**     PE1: iif(x,y,0)  pE2: x                Result: true
 **
 ** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
 ** Expr.iTable<0 then assume a table number given by iTab.
@@ -6488,6 +6544,9 @@ int sqlite3ExprImpliesExpr(
   ){
     return 1;
   }
+  if( sqlite3ExprIsIIF(pParse->db, pE1) ){
+    return sqlite3ExprImpliesExpr(pParse,pE1->x.pList->a[0].pExpr,pE2,iTab);
+  }
   return 0;
 }