Update sqlite to 3.7.3.

third_party/sqlite/src/src/expr.c

Index: third_party/sqlite/src/src/expr.c
diff --git a/third_party/sqlite/src/src/expr.c b/third_party/sqlite/src/src/expr.c
index 31a62b652a495fdf41afb877199d4c5840e966c3..30f043423b588e5f76b1044f460e727ffbb7dd01 100644
--- a/third_party/sqlite/src/src/expr.c
+++ b/third_party/sqlite/src/src/expr.c
@@ -56,24 +56,31 @@ char sqlite3ExprAffinity(Expr *pExpr){
 }
 
 /*
+** Set the explicit collating sequence for an expression to the
+** collating sequence supplied in the second argument.
+*/
+Expr *sqlite3ExprSetColl(Expr *pExpr, CollSeq *pColl){
+  if( pExpr && pColl ){
+    pExpr->pColl = pColl;
+    pExpr->flags |= EP_ExpCollate;
+  }
+  return pExpr;
+}
+
+/*
 ** Set the collating sequence for expression pExpr to be the collating
 ** sequence named by pToken.   Return a pointer to the revised expression.
 ** The collating sequence is marked as "explicit" using the EP_ExpCollate
 ** flag.  An explicit collating sequence will override implicit
 ** collating sequences.
 */
-Expr *sqlite3ExprSetColl(Parse *pParse, Expr *pExpr, Token *pCollName){
+Expr *sqlite3ExprSetCollByToken(Parse *pParse, Expr *pExpr, Token *pCollName){
   char *zColl = 0;            /* Dequoted name of collation sequence */
   CollSeq *pColl;
   sqlite3 *db = pParse->db;
   zColl = sqlite3NameFromToken(db, pCollName);
-  if( pExpr && zColl ){
-    pColl = sqlite3LocateCollSeq(pParse, zColl);
-    if( pColl ){
-      pExpr->pColl = pColl;
-      pExpr->flags |= EP_ExpCollate;
-    }
-  }
+  pColl = sqlite3LocateCollSeq(pParse, zColl);
+  sqlite3ExprSetColl(pExpr, pColl);
   sqlite3DbFree(db, zColl);
   return pExpr;
 }
@@ -152,7 +159,7 @@ static char comparisonAffinity(Expr *pExpr){
   char aff;
   assert( pExpr->op==TK_EQ || pExpr->op==TK_IN || pExpr->op==TK_LT ||
           pExpr->op==TK_GT || pExpr->op==TK_GE || pExpr->op==TK_LE ||
-          pExpr->op==TK_NE );
+          pExpr->op==TK_NE || pExpr->op==TK_IS || pExpr->op==TK_ISNOT );
   assert( pExpr->pLeft );
   aff = sqlite3ExprAffinity(pExpr->pLeft);
   if( pExpr->pRight ){
@@ -228,30 +235,6 @@ CollSeq *sqlite3BinaryCompareCollSeq(
 }
 
 /*
-** Generate the operands for a comparison operation.  Before
-** generating the code for each operand, set the EP_AnyAff
-** flag on the expression so that it will be able to used a
-** cached column value that has previously undergone an
-** affinity change.
-*/
-static void codeCompareOperands(
-  Parse *pParse,    /* Parsing and code generating context */
-  Expr *pLeft,      /* The left operand */
-  int *pRegLeft,    /* Register where left operand is stored */
-  int *pFreeLeft,   /* Free this register when done */
-  Expr *pRight,     /* The right operand */
-  int *pRegRight,   /* Register where right operand is stored */
-  int *pFreeRight   /* Write temp register for right operand there */
-){
-  while( pLeft->op==TK_UPLUS ) pLeft = pLeft->pLeft;
-  pLeft->flags |= EP_AnyAff;
-  *pRegLeft = sqlite3ExprCodeTemp(pParse, pLeft, pFreeLeft);
-  while( pRight->op==TK_UPLUS ) pRight = pRight->pLeft;
-  pRight->flags |= EP_AnyAff;
-  *pRegRight = sqlite3ExprCodeTemp(pParse, pRight, pFreeRight);
-}
-
-/*
 ** Generate code for a comparison operator.
 */
 static int codeCompare(
@@ -272,10 +255,6 @@ static int codeCompare(
   addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                            (void*)p4, P4_COLLSEQ);
   sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
-  if( (p5 & SQLITE_AFF_MASK)!=SQLITE_AFF_NONE ){
-    sqlite3ExprCacheAffinityChange(pParse, in1, 1);
-    sqlite3ExprCacheAffinityChange(pParse, in2, 1);
-  }
   return addr;
 }
 
@@ -571,22 +550,23 @@ void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
   if( z[1]==0 ){
     /* Wildcard of the form "?".  Assign the next variable number */
     assert( z[0]=='?' );
-    pExpr->iTable = ++pParse->nVar;
+    pExpr->iColumn = (ynVar)(++pParse->nVar);
   }else if( z[0]=='?' ){
     /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
     ** use it as the variable number */
-    int i;
-    pExpr->iTable = i = atoi((char*)&z[1]);
+    i64 i;
+    int bOk = 0==sqlite3Atoi64(&z[1], &i, sqlite3Strlen30(&z[1]), SQLITE_UTF8);
+    pExpr->iColumn = (ynVar)i;
     testcase( i==0 );
     testcase( i==1 );
     testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
     testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
-    if( i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
+    if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
       sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
           db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
     }
     if( i>pParse->nVar ){
-      pParse->nVar = i;
+      pParse->nVar = (int)i;
     }
   }else{
     /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
@@ -600,12 +580,12 @@ void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
       Expr *pE = pParse->apVarExpr[i];
       assert( pE!=0 );
       if( memcmp(pE->u.zToken, z, n)==0 && pE->u.zToken[n]==0 ){
-        pExpr->iTable = pE->iTable;
+        pExpr->iColumn = pE->iColumn;
         break;
       }
     }
     if( i>=pParse->nVarExpr ){
-      pExpr->iTable = ++pParse->nVar;
+      pExpr->iColumn = (ynVar)(++pParse->nVar);
       if( pParse->nVarExpr>=pParse->nVarExprAlloc-1 ){
         pParse->nVarExprAlloc += pParse->nVarExprAlloc + 10;
         pParse->apVarExpr =
@@ -627,11 +607,10 @@ void sqlite3ExprAssignVarNumber(Parse *pParse, Expr *pExpr){
 }
 
 /*
-** Clear an expression structure without deleting the structure itself.
-** Substructure is deleted.
+** Recursively delete an expression tree.
 */
-void sqlite3ExprClear(sqlite3 *db, Expr *p){
-  assert( p!=0 );
+void sqlite3ExprDelete(sqlite3 *db, Expr *p){
+  if( p==0 ) return;
   if( !ExprHasAnyProperty(p, EP_TokenOnly) ){
     sqlite3ExprDelete(db, p->pLeft);
     sqlite3ExprDelete(db, p->pRight);
@@ -644,14 +623,6 @@ void sqlite3ExprClear(sqlite3 *db, Expr *p){
       sqlite3ExprListDelete(db, p->x.pList);
     }
   }
-}
-
-/*
-** Recursively delete an expression tree.
-*/
-void sqlite3ExprDelete(sqlite3 *db, Expr *p){
-  if( p==0 ) return;
-  sqlite3ExprClear(db, p);
   if( !ExprHasProperty(p, EP_Static) ){
     sqlite3DbFree(db, p);
   }
@@ -1261,6 +1232,94 @@ int sqlite3ExprIsInteger(Expr *p, int *pValue){
 }
 
 /*
+** Return FALSE if there is no chance that the expression can be NULL.
+**
+** If the expression might be NULL or if the expression is too complex
+** to tell return TRUE.  
+**
+** This routine is used as an optimization, to skip OP_IsNull opcodes
+** when we know that a value cannot be NULL.  Hence, a false positive
+** (returning TRUE when in fact the expression can never be NULL) might
+** be a small performance hit but is otherwise harmless.  On the other
+** hand, a false negative (returning FALSE when the result could be NULL)
+** will likely result in an incorrect answer.  So when in doubt, return
+** TRUE.
+*/
+int sqlite3ExprCanBeNull(const Expr *p){
+  u8 op;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER:
+    case TK_STRING:
+    case TK_FLOAT:
+    case TK_BLOB:
+      return 0;
+    default:
+      return 1;
+  }
+}
+
+/*
+** Generate an OP_IsNull instruction that tests register iReg and jumps
+** to location iDest if the value in iReg is NULL.  The value in iReg 
+** was computed by pExpr.  If we can look at pExpr at compile-time and
+** determine that it can never generate a NULL, then the OP_IsNull operation
+** can be omitted.
+*/
+void sqlite3ExprCodeIsNullJump(
+  Vdbe *v,            /* The VDBE under construction */
+  const Expr *pExpr,  /* Only generate OP_IsNull if this expr can be NULL */
+  int iReg,           /* Test the value in this register for NULL */
+  int iDest           /* Jump here if the value is null */
+){
+  if( sqlite3ExprCanBeNull(pExpr) ){
+    sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iDest);
+  }
+}
+
+/*
+** Return TRUE if the given expression is a constant which would be
+** unchanged by OP_Affinity with the affinity given in the second
+** argument.
+**
+** This routine is used to determine if the OP_Affinity operation
+** can be omitted.  When in doubt return FALSE.  A false negative
+** is harmless.  A false positive, however, can result in the wrong
+** answer.
+*/
+int sqlite3ExprNeedsNoAffinityChange(const Expr *p, char aff){
+  u8 op;
+  if( aff==SQLITE_AFF_NONE ) return 1;
+  while( p->op==TK_UPLUS || p->op==TK_UMINUS ){ p = p->pLeft; }
+  op = p->op;
+  if( op==TK_REGISTER ) op = p->op2;
+  switch( op ){
+    case TK_INTEGER: {
+      return aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_FLOAT: {
+      return aff==SQLITE_AFF_REAL || aff==SQLITE_AFF_NUMERIC;
+    }
+    case TK_STRING: {
+      return aff==SQLITE_AFF_TEXT;
+    }
+    case TK_BLOB: {
+      return 1;
+    }
+    case TK_COLUMN: {
+      assert( p->iTable>=0 );  /* p cannot be part of a CHECK constraint */
+      return p->iColumn<0
+          && (aff==SQLITE_AFF_INTEGER || aff==SQLITE_AFF_NUMERIC);
+    }
+    default: {
+      return 0;
+    }
+  }
+}
+
+/*
 ** Return TRUE if the given string is a row-id column name.
 */
 int sqlite3IsRowid(const char *z){
@@ -1347,16 +1406,16 @@ static int isCandidateForInOpt(Select *p){
 ** When the b-tree is being used for membership tests, the calling function
 ** needs to know whether or not the structure contains an SQL NULL 
 ** value in order to correctly evaluate expressions like "X IN (Y, Z)".
-** If there is a chance that the b-tree might contain a NULL value at
+** If there is any chance that the (...) might contain a NULL value at
 ** runtime, then a register is allocated and the register number written
-** to *prNotFound. If there is no chance that the b-tree contains a
+** to *prNotFound. If there is no chance that the (...) contains a
 ** NULL value, then *prNotFound is left unchanged.
 **
 ** If a register is allocated and its location stored in *prNotFound, then
-** its initial value is NULL. If the b-tree does not remain constant
-** for the duration of the query (i.e. the SELECT that generates the b-tree
+** its initial value is NULL.  If the (...) does not remain constant
+** for the duration of the query (i.e. the SELECT within the (...)
 ** is a correlated subquery) then the value of the allocated register is
-** reset to NULL each time the b-tree is repopulated. This allows the
+** reset to NULL each time the subquery is rerun. This allows the
 ** caller to use vdbe code equivalent to the following:
 **
 **   if( register==NULL ){
@@ -1374,6 +1433,8 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
   int iTab = pParse->nTab++;            /* Cursor of the RHS table */
   int mustBeUnique = (prNotFound==0);   /* True if RHS must be unique */
 
+  assert( pX->op==TK_IN );
+
   /* Check to see if an existing table or index can be used to
   ** satisfy the query.  This is preferable to generating a new 
   ** ephemeral table.
@@ -1451,17 +1512,23 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
   }
 
   if( eType==0 ){
-    /* Could not found an existing able or index to use as the RHS b-tree.
+    /* Could not found an existing table or index to use as the RHS b-tree.
     ** We will have to generate an ephemeral table to do the job.
     */
+    double savedNQueryLoop = pParse->nQueryLoop;
     int rMayHaveNull = 0;
     eType = IN_INDEX_EPH;
     if( prNotFound ){
       *prNotFound = rMayHaveNull = ++pParse->nMem;
-    }else if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
-      eType = IN_INDEX_ROWID;
+    }else{
+      testcase( pParse->nQueryLoop>(double)1 );
+      pParse->nQueryLoop = (double)1;
+      if( pX->pLeft->iColumn<0 && !ExprHasAnyProperty(pX, EP_xIsSelect) ){
+        eType = IN_INDEX_ROWID;
+      }
     }
     sqlite3CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
+    pParse->nQueryLoop = savedNQueryLoop;
   }else{
     pX->iTable = iTab;
   }
@@ -1470,8 +1537,8 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
 #endif
 
 /*
-** Generate code for scalar subqueries used as an expression
-** and IN operators.  Examples:
+** Generate code for scalar subqueries used as a subquery expression, EXISTS,
+** or IN operators.  Examples:
 **
 **     (SELECT a FROM b)          -- subquery
 **     EXISTS (SELECT a FROM b)   -- EXISTS subquery
@@ -1498,17 +1565,21 @@ int sqlite3FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
 ** If rMayHaveNull is zero, that means that the subquery is being used
 ** for membership testing only.  There is no need to initialize any
 ** registers to indicate the presense or absence of NULLs on the RHS.
+**
+** For a SELECT or EXISTS operator, return the register that holds the
+** result.  For IN operators or if an error occurs, the return value is 0.
 */
 #ifndef SQLITE_OMIT_SUBQUERY
-void sqlite3CodeSubselect(
+int sqlite3CodeSubselect(
   Parse *pParse,          /* Parsing context */
   Expr *pExpr,            /* The IN, SELECT, or EXISTS operator */
   int rMayHaveNull,       /* Register that records whether NULLs exist in RHS */
   int isRowid             /* If true, LHS of IN operator is a rowid */
 ){
   int testAddr = 0;                       /* One-time test address */
+  int rReg = 0;                           /* Register storing resulting */
   Vdbe *v = sqlite3GetVdbe(pParse);
-  if( NEVER(v==0) ) return;
+  if( NEVER(v==0) ) return 0;
   sqlite3ExprCachePush(pParse);
 
   /* This code must be run in its entirety every time it is encountered
@@ -1530,10 +1601,10 @@ void sqlite3CodeSubselect(
 
   switch( pExpr->op ){
     case TK_IN: {
-      char affinity;
-      KeyInfo keyInfo;
-      int addr;        /* Address of OP_OpenEphemeral instruction */
-      Expr *pLeft = pExpr->pLeft;
+      char affinity;              /* Affinity of the LHS of the IN */
+      KeyInfo keyInfo;            /* Keyinfo for the generated table */
+      int addr;                   /* Address of OP_OpenEphemeral instruction */
+      Expr *pLeft = pExpr->pLeft; /* the LHS of the IN operator */
 
       if( rMayHaveNull ){
         sqlite3VdbeAddOp2(v, OP_Null, 0, rMayHaveNull);
@@ -1542,7 +1613,7 @@ void sqlite3CodeSubselect(
       affinity = sqlite3ExprAffinity(pLeft);
 
       /* Whether this is an 'x IN(SELECT...)' or an 'x IN(<exprlist>)'
-      ** expression it is handled the same way. A virtual table is 
+      ** expression it is handled the same way.  An ephemeral table is 
       ** filled with single-field index keys representing the results
       ** from the SELECT or the <exprlist>.
       **
@@ -1556,6 +1627,7 @@ void sqlite3CodeSubselect(
       */
       pExpr->iTable = pParse->nTab++;
       addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pExpr->iTable, !isRowid);
+      if( rMayHaveNull==0 ) sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
       memset(&keyInfo, 0, sizeof(keyInfo));
       keyInfo.nField = 1;
 
@@ -1573,14 +1645,14 @@ void sqlite3CodeSubselect(
         dest.affinity = (u8)affinity;
         assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
         if( sqlite3Select(pParse, pExpr->x.pSelect, &dest) ){
-          return;
+          return 0;
         }
         pEList = pExpr->x.pSelect->pEList;
         if( ALWAYS(pEList!=0 && pEList->nExpr>0) ){ 
           keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
               pEList->a[0].pExpr);
         }
-      }else if( pExpr->x.pList!=0 ){
+      }else if( ALWAYS(pExpr->x.pList!=0) ){
         /* Case 2:     expr IN (exprlist)
         **
         ** For each expression, build an index key from the evaluation and
@@ -1604,6 +1676,7 @@ void sqlite3CodeSubselect(
         sqlite3VdbeAddOp2(v, OP_Null, 0, r2);
         for(i=pList->nExpr, pItem=pList->a; i>0; i--, pItem++){
           Expr *pE2 = pItem->pExpr;
+          int iValToIns;
 
           /* If the expression is not constant then we will need to
           ** disable the test that was generated above that makes sure
@@ -1616,14 +1689,19 @@ void sqlite3CodeSubselect(
           }
 
           /* Evaluate the expression and insert it into the temp table */
-          r3 = sqlite3ExprCodeTarget(pParse, pE2, r1);
-          if( isRowid ){
-            sqlite3VdbeAddOp2(v, OP_MustBeInt, r3, sqlite3VdbeCurrentAddr(v)+2);
-            sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
+          if( isRowid && sqlite3ExprIsInteger(pE2, &iValToIns) ){
+            sqlite3VdbeAddOp3(v, OP_InsertInt, pExpr->iTable, r2, iValToIns);
           }else{
-            sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
-            sqlite3ExprCacheAffinityChange(pParse, r3, 1);
-            sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
+            r3 = sqlite3ExprCodeTarget(pParse, pE2, r1);
+            if( isRowid ){
+              sqlite3VdbeAddOp2(v, OP_MustBeInt, r3,
+                                sqlite3VdbeCurrentAddr(v)+2);
+              sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
+            }else{
+              sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
+              sqlite3ExprCacheAffinityChange(pParse, r3, 1);
+              sqlite3VdbeAddOp2(v, OP_IdxInsert, pExpr->iTable, r2);
+            }
           }
         }
         sqlite3ReleaseTempReg(pParse, r1);
@@ -1644,7 +1722,6 @@ void sqlite3CodeSubselect(
       ** an integer 0 (not exists) or 1 (exists) into a memory cell
       ** and record that memory cell in iColumn.
       */
-      static const Token one = { "1", 1 };  /* Token for literal value 1 */
       Select *pSel;                         /* SELECT statement to encode */
       SelectDest dest;                      /* How to deal with SELECt result */
 
@@ -1665,11 +1742,12 @@ void sqlite3CodeSubselect(
         VdbeComment((v, "Init EXISTS result"));
       }
       sqlite3ExprDelete(pParse->db, pSel->pLimit);
-      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
+      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0,
+                                  &sqlite3IntTokens[1]);
       if( sqlite3Select(pParse, pSel, &dest) ){
-        return;
+        return 0;
       }
-      pExpr->iColumn = (i16)dest.iParm;
+      rReg = dest.iParm;
       ExprSetIrreducible(pExpr);
       break;
     }
@@ -1680,7 +1758,141 @@ void sqlite3CodeSubselect(
   }
   sqlite3ExprCachePop(pParse, 1);
 
-  return;
+  return rReg;
+}
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+#ifndef SQLITE_OMIT_SUBQUERY
+/*
+** Generate code for an IN expression.
+**
+**      x IN (SELECT ...)
+**      x IN (value, value, ...)
+**
+** The left-hand side (LHS) is a scalar expression.  The right-hand side (RHS)
+** is an array of zero or more values.  The expression is true if the LHS is
+** contained within the RHS.  The value of the expression is unknown (NULL)
+** if the LHS is NULL or if the LHS is not contained within the RHS and the
+** RHS contains one or more NULL values.
+**
+** This routine generates code will jump to destIfFalse if the LHS is not 
+** contained within the RHS.  If due to NULLs we cannot determine if the LHS
+** is contained in the RHS then jump to destIfNull.  If the LHS is contained
+** within the RHS then fall through.
+*/
+static void sqlite3ExprCodeIN(
+  Parse *pParse,        /* Parsing and code generating context */
+  Expr *pExpr,          /* The IN expression */
+  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
+  int destIfNull        /* Jump here if the results are unknown due to NULLs */
+){
+  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
+  char affinity;        /* Comparison affinity to use */
+  int eType;            /* Type of the RHS */
+  int r1;               /* Temporary use register */
+  Vdbe *v;              /* Statement under construction */
+
+  /* Compute the RHS.   After this step, the table with cursor
+  ** pExpr->iTable will contains the values that make up the RHS.
+  */
+  v = pParse->pVdbe;
+  assert( v!=0 );       /* OOM detected prior to this routine */
+  VdbeNoopComment((v, "begin IN expr"));
+  eType = sqlite3FindInIndex(pParse, pExpr, &rRhsHasNull);
+
+  /* Figure out the affinity to use to create a key from the results
+  ** of the expression. affinityStr stores a static string suitable for
+  ** P4 of OP_MakeRecord.
+  */
+  affinity = comparisonAffinity(pExpr);
+
+  /* Code the LHS, the <expr> from "<expr> IN (...)".
+  */
+  sqlite3ExprCachePush(pParse);
+  r1 = sqlite3GetTempReg(pParse);
+  sqlite3ExprCode(pParse, pExpr->pLeft, r1);
+
+  /* If the LHS is NULL, then the result is either false or NULL depending
+  ** on whether the RHS is empty or not, respectively.
+  */
+  if( destIfNull==destIfFalse ){
+    /* Shortcut for the common case where the false and NULL outcomes are
+    ** the same. */
+    sqlite3VdbeAddOp2(v, OP_IsNull, r1, destIfNull);
+  }else{
+    int addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, r1);
+    sqlite3VdbeAddOp2(v, OP_Rewind, pExpr->iTable, destIfFalse);
+    sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfNull);
+    sqlite3VdbeJumpHere(v, addr1);
+  }
+
+  if( eType==IN_INDEX_ROWID ){
+    /* In this case, the RHS is the ROWID of table b-tree
+    */
+    sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, destIfFalse);
+    sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, destIfFalse, r1);
+  }else{
+    /* In this case, the RHS is an index b-tree.
+    */
+    sqlite3VdbeAddOp4(v, OP_Affinity, r1, 1, 0, &affinity, 1);
+
+    /* If the set membership test fails, then the result of the 
+    ** "x IN (...)" expression must be either 0 or NULL. If the set
+    ** contains no NULL values, then the result is 0. If the set 
+    ** contains one or more NULL values, then the result of the
+    ** expression is also NULL.
+    */
+    if( rRhsHasNull==0 || destIfFalse==destIfNull ){
+      /* This branch runs if it is known at compile time that the RHS
+      ** cannot contain NULL values. This happens as the result
+      ** of a "NOT NULL" constraint in the database schema.
+      **
+      ** Also run this branch if NULL is equivalent to FALSE
+      ** for this particular IN operator.
+      */
+      sqlite3VdbeAddOp4Int(v, OP_NotFound, pExpr->iTable, destIfFalse, r1, 1);
+
+    }else{
+      /* In this branch, the RHS of the IN might contain a NULL and
+      ** the presence of a NULL on the RHS makes a difference in the
+      ** outcome.
+      */
+      int j1, j2, j3;
+
+      /* First check to see if the LHS is contained in the RHS.  If so,
+      ** then the presence of NULLs in the RHS does not matter, so jump
+      ** over all of the code that follows.
+      */
+      j1 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, r1, 1);
+
+      /* Here we begin generating code that runs if the LHS is not
+      ** contained within the RHS.  Generate additional code that
+      ** tests the RHS for NULLs.  If the RHS contains a NULL then
+      ** jump to destIfNull.  If there are no NULLs in the RHS then
+      ** jump to destIfFalse.
+      */
+      j2 = sqlite3VdbeAddOp1(v, OP_NotNull, rRhsHasNull);
+      j3 = sqlite3VdbeAddOp4Int(v, OP_Found, pExpr->iTable, 0, rRhsHasNull, 1);
+      sqlite3VdbeAddOp2(v, OP_Integer, -1, rRhsHasNull);
+      sqlite3VdbeJumpHere(v, j3);
+      sqlite3VdbeAddOp2(v, OP_AddImm, rRhsHasNull, 1);
+      sqlite3VdbeJumpHere(v, j2);
+
+      /* Jump to the appropriate target depending on whether or not
+      ** the RHS contains a NULL
+      */
+      sqlite3VdbeAddOp2(v, OP_If, rRhsHasNull, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, destIfFalse);
+
+      /* The OP_Found at the top of this branch jumps here when true, 
+      ** causing the overall IN expression evaluation to fall through.
+      */
+      sqlite3VdbeJumpHere(v, j1);
+    }
+  }
+  sqlite3ReleaseTempReg(pParse, r1);
+  sqlite3ExprCachePop(pParse, 1);
+  VdbeComment((v, "end IN expr"));
 }
 #endif /* SQLITE_OMIT_SUBQUERY */
 
@@ -1695,6 +1907,7 @@ static char *dup8bytes(Vdbe *v, const char *in){
   return out;
 }
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Generate an instruction that will put the floating point
 ** value described by z[0..n-1] into register iMem.
@@ -1707,40 +1920,45 @@ static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
   if( ALWAYS(z!=0) ){
     double value;
     char *zV;
-    sqlite3AtoF(z, &value);
+    sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
     assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
     if( negateFlag ) value = -value;
     zV = dup8bytes(v, (char*)&value);
     sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
   }
 }
+#endif
 
 
 /*
 ** Generate an instruction that will put the integer describe by
 ** text z[0..n-1] into register iMem.
 **
-** The z[] string will probably not be zero-terminated.  But the 
-** z[n] character is guaranteed to be something that does not look
-** like the continuation of the number.
+** Expr.u.zToken is always UTF8 and zero-terminated.
 */
-static void codeInteger(Vdbe *v, Expr *pExpr, int negFlag, int iMem){
+static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
+  Vdbe *v = pParse->pVdbe;
   if( pExpr->flags & EP_IntValue ){
     int i = pExpr->u.iValue;
     if( negFlag ) i = -i;
     sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
   }else{
+    int c;
+    i64 value;
     const char *z = pExpr->u.zToken;
     assert( z!=0 );
-    if( sqlite3FitsIn64Bits(z, negFlag) ){
-      i64 value;
+    c = sqlite3Atoi64(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
+    if( c==0 || (c==2 && negFlag) ){
       char *zV;
-      sqlite3Atoi64(z, &value);
-      if( negFlag ) value = -value;
+      if( negFlag ){ value = -value; }
       zV = dup8bytes(v, (char*)&value);
       sqlite3VdbeAddOp4(v, OP_Int64, 0, iMem, 0, zV, P4_INT64);
     }else{
+#ifdef SQLITE_OMIT_FLOATING_POINT
+      sqlite3ErrorMsg(pParse, "oversized integer: %s%s", negFlag ? "-" : "", z);
+#else
       codeReal(v, z, negFlag, iMem);
+#endif
     }
   }
 }
@@ -1771,17 +1989,31 @@ void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
   assert( iReg>0 );  /* Register numbers are always positive */
   assert( iCol>=-1 && iCol<32768 );  /* Finite column numbers */
 
-  /* First replace any existing entry */
+  /* The SQLITE_ColumnCache flag disables the column cache.  This is used
+  ** for testing only - to verify that SQLite always gets the same answer
+  ** with and without the column cache.
+  */
+  if( pParse->db->flags & SQLITE_ColumnCache ) return;
+
+  /* First replace any existing entry.
+  **
+  ** Actually, the way the column cache is currently used, we are guaranteed
+  ** that the object will never already be in cache.  Verify this guarantee.
+  */
+#ifndef NDEBUG
   for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
+#if 0 /* This code wold remove the entry from the cache if it existed */
     if( p->iReg && p->iTable==iTab && p->iColumn==iCol ){
       cacheEntryClear(pParse, p);
       p->iLevel = pParse->iCacheLevel;
       p->iReg = iReg;
-      p->affChange = 0;
       p->lru = pParse->iCacheCnt++;
       return;
     }
+#endif
+    assert( p->iReg==0 || p->iTable!=iTab || p->iColumn!=iCol );
   }
+#endif
 
   /* Find an empty slot and replace it */
   for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
@@ -1790,7 +2022,6 @@ void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
       p->iTable = iTab;
       p->iColumn = iCol;
       p->iReg = iReg;
-      p->affChange = 0;
       p->tempReg = 0;
       p->lru = pParse->iCacheCnt++;
       return;
@@ -1812,7 +2043,6 @@ void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
     p->iTable = iTab;
     p->iColumn = iCol;
     p->iReg = iReg;
-    p->affChange = 0;
     p->tempReg = 0;
     p->lru = pParse->iCacheCnt++;
     return;
@@ -1820,14 +2050,16 @@ void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
 }
 
 /*
-** Indicate that a register is being overwritten.  Purge the register
-** from the column cache.
+** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
+** Purge the range of registers from the column cache.
 */
-void sqlite3ExprCacheRemove(Parse *pParse, int iReg){
+void sqlite3ExprCacheRemove(Parse *pParse, int iReg, int nReg){
   int i;
+  int iLast = iReg + nReg - 1;
   struct yColCache *p;
   for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
-    if( p->iReg==iReg ){
+    int r = p->iReg;
+    if( r>=iReg && r<=iLast ){
       cacheEntryClear(pParse, p);
       p->iReg = 0;
     }
@@ -1879,6 +2111,27 @@ static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
 }
 
 /*
+** Generate code to extract the value of the iCol-th column of a table.
+*/
+void sqlite3ExprCodeGetColumnOfTable(
+  Vdbe *v,        /* The VDBE under construction */
+  Table *pTab,    /* The table containing the value */
+  int iTabCur,    /* The cursor for this table */
+  int iCol,       /* Index of the column to extract */
+  int regOut      /* Extract the valud into this register */
+){
+  if( iCol<0 || iCol==pTab->iPKey ){
+    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
+  }else{
+    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
+    sqlite3VdbeAddOp3(v, op, iTabCur, iCol, regOut);
+  }
+  if( iCol>=0 ){
+    sqlite3ColumnDefault(v, pTab, iCol, regOut);
+  }
+}
+
+/*
 ** 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
@@ -1886,41 +2139,27 @@ static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
 **
 ** 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.
-**
-** This routine might attempt to reuse the value of the column that
-** has already been loaded into a register.  The value will always
-** be used if it has not undergone any affinity changes.  But if
-** an affinity change has occurred, then the cached value will only be
-** used if allowAffChng is true.
 */
 int sqlite3ExprCodeGetColumn(
   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 allowAffChng /* True if prior affinity changes are OK */
+  int iReg         /* Store results here */
 ){
   Vdbe *v = pParse->pVdbe;
   int i;
   struct yColCache *p;
 
   for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
-    if( p->iReg>0 && p->iTable==iTable && p->iColumn==iColumn
-           && (!p->affChange || allowAffChng) ){
+    if( p->iReg>0 && p->iTable==iTable && p->iColumn==iColumn ){
       p->lru = pParse->iCacheCnt++;
       sqlite3ExprCachePinRegister(pParse, p->iReg);
       return p->iReg;
     }
   }  
   assert( v!=0 );
-  if( iColumn<0 ){
-    sqlite3VdbeAddOp2(v, OP_Rowid, iTable, iReg);
-  }else if( ALWAYS(pTab!=0) ){
-    int op = IsVirtual(pTab) ? OP_VColumn : OP_Column;
-    sqlite3VdbeAddOp3(v, op, iTable, iColumn, iReg);
-    sqlite3ColumnDefault(v, pTab, iColumn, iReg);
-  }
+  sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
   sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
   return iReg;
 }
@@ -1945,15 +2184,7 @@ void sqlite3ExprCacheClear(Parse *pParse){
 ** registers starting with iStart.
 */
 void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
-  int iEnd = iStart + iCount - 1;
-  int i;
-  struct yColCache *p;
-  for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
-    int r = p->iReg;
-    if( r>=iStart && r<=iEnd ){
-      p->affChange = 1;
-    }
-  }
+  sqlite3ExprCacheRemove(pParse, iStart, iCount);
 }
 
 /*
@@ -1985,86 +2216,24 @@ void sqlite3ExprCodeCopy(Parse *pParse, int iFrom, int iTo, int nReg){
   }
 }
 
+#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
 /*
 ** Return true if any register in the range iFrom..iTo (inclusive)
 ** is used as part of the column cache.
+**
+** This routine is used within assert() and testcase() macros only
+** and does not appear in a normal build.
 */
 static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
   int i;
   struct yColCache *p;
   for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
     int r = p->iReg;
-    if( r>=iFrom && r<=iTo ) return 1;
+    if( r>=iFrom && r<=iTo ) return 1;    /*NO_TEST*/
   }
   return 0;
 }
-
-/*
-** If the last instruction coded is an ephemeral copy of any of
-** the registers in the nReg registers beginning with iReg, then
-** convert the last instruction from OP_SCopy to OP_Copy.
-*/
-void sqlite3ExprHardCopy(Parse *pParse, int iReg, int nReg){
-  VdbeOp *pOp;
-  Vdbe *v;
-
-  assert( pParse->db->mallocFailed==0 );
-  v = pParse->pVdbe;
-  assert( v!=0 );
-  pOp = sqlite3VdbeGetOp(v, -1);
-  assert( pOp!=0 );
-  if( pOp->opcode==OP_SCopy && pOp->p1>=iReg && pOp->p1<iReg+nReg ){
-    pOp->opcode = OP_Copy;
-  }
-}
-
-/*
-** Generate code to store the value of the iAlias-th alias in register
-** target.  The first time this is called, pExpr is evaluated to compute
-** the value of the alias.  The value is stored in an auxiliary register
-** and the number of that register is returned.  On subsequent calls,
-** the register number is returned without generating any code.
-**
-** Note that in order for this to work, code must be generated in the
-** same order that it is executed.
-**
-** Aliases are numbered starting with 1.  So iAlias is in the range
-** of 1 to pParse->nAlias inclusive.  
-**
-** pParse->aAlias[iAlias-1] records the register number where the value
-** of the iAlias-th alias is stored.  If zero, that means that the
-** alias has not yet been computed.
-*/
-static int codeAlias(Parse *pParse, int iAlias, Expr *pExpr, int target){
-#if 0
-  sqlite3 *db = pParse->db;
-  int iReg;
-  if( pParse->nAliasAlloc<pParse->nAlias ){
-    pParse->aAlias = sqlite3DbReallocOrFree(db, pParse->aAlias,
-                                 sizeof(pParse->aAlias[0])*pParse->nAlias );
-    testcase( db->mallocFailed && pParse->nAliasAlloc>0 );
-    if( db->mallocFailed ) return 0;
-    memset(&pParse->aAlias[pParse->nAliasAlloc], 0,
-           (pParse->nAlias-pParse->nAliasAlloc)*sizeof(pParse->aAlias[0]));
-    pParse->nAliasAlloc = pParse->nAlias;
-  }
-  assert( iAlias>0 && iAlias<=pParse->nAlias );
-  iReg = pParse->aAlias[iAlias-1];
-  if( iReg==0 ){
-    if( pParse->iCacheLevel>0 ){
-      iReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
-    }else{
-      iReg = ++pParse->nMem;
-      sqlite3ExprCode(pParse, pExpr, iReg);
-      pParse->aAlias[iAlias-1] = iReg;
-    }
-  }
-  return iReg;
-#else
-  UNUSED_PARAMETER(iAlias);
-  return sqlite3ExprCodeTarget(pParse, pExpr, target);
-#endif
-}
+#endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
 
 /*
 ** Generate code into the current Vdbe to evaluate the given
@@ -2118,22 +2287,22 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         assert( pParse->ckBase>0 );
         inReg = pExpr->iColumn + pParse->ckBase;
       }else{
-        testcase( (pExpr->flags & EP_AnyAff)!=0 );
         inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
-                                 pExpr->iColumn, pExpr->iTable, target,
-                                 pExpr->flags & EP_AnyAff);
+                                 pExpr->iColumn, pExpr->iTable, target);
       }
       break;
     }
     case TK_INTEGER: {
-      codeInteger(v, pExpr, 0, target);
+      codeInteger(pParse, pExpr, 0, target);
       break;
     }
+#ifndef SQLITE_OMIT_FLOATING_POINT
     case TK_FLOAT: {
       assert( !ExprHasProperty(pExpr, EP_IntValue) );
       codeReal(v, pExpr->u.zToken, 0, target);
       break;
     }
+#endif
     case TK_STRING: {
       assert( !ExprHasProperty(pExpr, EP_IntValue) );
       sqlite3VdbeAddOp4(v, OP_String8, 0, target, 0, pExpr->u.zToken, 0);
@@ -2160,27 +2329,12 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
     }
 #endif
     case TK_VARIABLE: {
-      VdbeOp *pOp;
       assert( !ExprHasProperty(pExpr, EP_IntValue) );
       assert( pExpr->u.zToken!=0 );
       assert( pExpr->u.zToken[0]!=0 );
-      if( pExpr->u.zToken[1]==0
-         && (pOp = sqlite3VdbeGetOp(v, -1))->opcode==OP_Variable
-         && pOp->p1+pOp->p3==pExpr->iTable
-         && pOp->p2+pOp->p3==target
-         && pOp->p4.z==0
-      ){
-        /* If the previous instruction was a copy of the previous unnamed
-        ** parameter into the previous register, then simply increment the
-        ** repeat count on the prior instruction rather than making a new
-        ** instruction.
-        */
-        pOp->p3++;
-      }else{
-        sqlite3VdbeAddOp3(v, OP_Variable, pExpr->iTable, target, 1);
-        if( pExpr->u.zToken[1]!=0 ){
-          sqlite3VdbeChangeP4(v, -1, pExpr->u.zToken, 0);
-        }
+      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
+      if( pExpr->u.zToken[1]!=0 ){
+        sqlite3VdbeChangeP4(v, -1, pExpr->u.zToken, 0);
       }
       break;
     }
@@ -2189,7 +2343,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       break;
     }
     case TK_AS: {
-      inReg = codeAlias(pParse, pExpr->iTable, pExpr->pLeft, target);
+      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
       break;
     }
 #ifndef SQLITE_OMIT_CAST
@@ -2238,14 +2392,27 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       testcase( op==TK_GE );
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, inReg, SQLITE_STOREP2);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, inReg, SQLITE_STOREP2 | SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_AND:
     case TK_OR:
     case TK_PLUS:
@@ -2290,11 +2457,13 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
     case TK_UMINUS: {
       Expr *pLeft = pExpr->pLeft;
       assert( pLeft );
-      if( pLeft->op==TK_FLOAT ){
+      if( pLeft->op==TK_INTEGER ){
+        codeInteger(pParse, pLeft, 1, target);
+#ifndef SQLITE_OMIT_FLOATING_POINT
+      }else if( pLeft->op==TK_FLOAT ){
         assert( !ExprHasProperty(pExpr, EP_IntValue) );
         codeReal(v, pLeft->u.zToken, 1, target);
-      }else if( pLeft->op==TK_INTEGER ){
-        codeInteger(v, pLeft, 1, target);
+#endif
       }else{
         regFree1 = r1 = sqlite3GetTempReg(pParse);
         sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
@@ -2371,6 +2540,27 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         sqlite3ErrorMsg(pParse, "unknown function: %.*s()", nId, zId);
         break;
       }
+
+      /* Attempt a direct implementation of the built-in COALESCE() and
+      ** IFNULL() functions.  This avoids unnecessary evalation of
+      ** arguments past the first non-NULL argument.
+      */
+      if( pDef->flags & SQLITE_FUNC_COALESCE ){
+        int endCoalesce = sqlite3VdbeMakeLabel(v);
+        assert( nFarg>=2 );
+        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+        for(i=1; i<nFarg; i++){
+          sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
+          sqlite3ExprCacheRemove(pParse, target, 1);
+          sqlite3ExprCachePush(pParse);
+          sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
+          sqlite3ExprCachePop(pParse, 1);
+        }
+        sqlite3VdbeResolveLabel(v, endCoalesce);
+        break;
+      }
+
+
       if( pFarg ){
         r1 = sqlite3GetTempRange(pParse, nFarg);
         sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
@@ -2416,7 +2606,6 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       if( nFarg ){
         sqlite3ReleaseTempRange(pParse, r1, nFarg);
       }
-      sqlite3ExprCacheAffinityChange(pParse, r1, nFarg);
       break;
     }
 #ifndef SQLITE_OMIT_SUBQUERY
@@ -2424,100 +2613,23 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
     case TK_SELECT: {
       testcase( op==TK_EXISTS );
       testcase( op==TK_SELECT );
-      sqlite3CodeSubselect(pParse, pExpr, 0, 0);
-      inReg = pExpr->iColumn;
+      inReg = sqlite3CodeSubselect(pParse, pExpr, 0, 0);
       break;
     }
     case TK_IN: {
-      int rNotFound = 0;
-      int rMayHaveNull = 0;
-      int j2, j3, j4, j5;
-      char affinity;
-      int eType;
-
-      VdbeNoopComment((v, "begin IN expr r%d", target));
-      eType = sqlite3FindInIndex(pParse, pExpr, &rMayHaveNull);
-      if( rMayHaveNull ){
-        rNotFound = ++pParse->nMem;
-      }
-
-      /* Figure out the affinity to use to create a key from the results
-      ** of the expression. affinityStr stores a static string suitable for
-      ** P4 of OP_MakeRecord.
-      */
-      affinity = comparisonAffinity(pExpr);
-
-
-      /* Code the <expr> from "<expr> IN (...)". The temporary table
-      ** pExpr->iTable contains the values that make up the (...) set.
-      */
-      sqlite3ExprCachePush(pParse);
-      sqlite3ExprCode(pParse, pExpr->pLeft, target);
-      j2 = sqlite3VdbeAddOp1(v, OP_IsNull, target);
-      if( eType==IN_INDEX_ROWID ){
-        j3 = sqlite3VdbeAddOp1(v, OP_MustBeInt, target);
-        j4 = sqlite3VdbeAddOp3(v, OP_NotExists, pExpr->iTable, 0, target);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp0(v, OP_Goto);
-        sqlite3VdbeJumpHere(v, j3);
-        sqlite3VdbeJumpHere(v, j4);
-        sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-      }else{
-        r2 = regFree2 = sqlite3GetTempReg(pParse);
-
-        /* Create a record and test for set membership. If the set contains
-        ** the value, then jump to the end of the test code. The target
-        ** register still contains the true (1) value written to it earlier.
-        */
-        sqlite3VdbeAddOp4(v, OP_MakeRecord, target, 1, r2, &affinity, 1);
-        sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
-        j5 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, r2);
-
-        /* If the set membership test fails, then the result of the 
-        ** "x IN (...)" expression must be either 0 or NULL. If the set
-        ** contains no NULL values, then the result is 0. If the set 
-        ** contains one or more NULL values, then the result of the
-        ** expression is also NULL.
-        */
-        if( rNotFound==0 ){
-          /* This branch runs if it is known at compile time (now) that 
-          ** the set contains no NULL values. This happens as the result
-          ** of a "NOT NULL" constraint in the database schema. No need
-          ** to test the data structure at runtime in this case.
-          */
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, target);
-        }else{
-          /* This block populates the rNotFound register with either NULL
-          ** or 0 (an integer value). If the data structure contains one
-          ** or more NULLs, then set rNotFound to NULL. Otherwise, set it
-          ** to 0. If register rMayHaveNull is already set to some value
-          ** other than NULL, then the test has already been run and 
-          ** rNotFound is already populated.
-          */
-          static const char nullRecord[] = { 0x02, 0x00 };
-          j3 = sqlite3VdbeAddOp1(v, OP_NotNull, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Null, 0, rNotFound);
-          sqlite3VdbeAddOp4(v, OP_Blob, 2, rMayHaveNull, 0, 
-                             nullRecord, P4_STATIC);
-          j4 = sqlite3VdbeAddOp3(v, OP_Found, pExpr->iTable, 0, rMayHaveNull);
-          sqlite3VdbeAddOp2(v, OP_Integer, 0, rNotFound);
-          sqlite3VdbeJumpHere(v, j4);
-          sqlite3VdbeJumpHere(v, j3);
-
-          /* Copy the value of register rNotFound (which is either NULL or 0)
-          ** into the target register. This will be the result of the
-          ** expression.
-          */
-          sqlite3VdbeAddOp2(v, OP_Copy, rNotFound, target);
-        }
-      }
-      sqlite3VdbeJumpHere(v, j2);
-      sqlite3VdbeJumpHere(v, j5);
-      sqlite3ExprCachePop(pParse, 1);
-      VdbeComment((v, "end IN expr r%d", target));
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = sqlite3VdbeMakeLabel(v);
+      sqlite3VdbeAddOp2(v, OP_Null, 0, target);
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Integer, 1, target);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
+      sqlite3VdbeAddOp2(v, OP_AddImm, target, 0);
+      sqlite3VdbeResolveLabel(v, destIfNull);
       break;
     }
-#endif
+#endif /* SQLITE_OMIT_SUBQUERY */
+
+
     /*
     **    x BETWEEN y AND z
     **
@@ -2534,8 +2646,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       struct ExprList_item *pLItem = pExpr->x.pList->a;
       Expr *pRight = pLItem->pExpr;
 
-      codeCompareOperands(pParse, pLeft, &r1, &regFree1,
-                                  pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pRight, &regFree2);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       r3 = sqlite3GetTempReg(pParse);
@@ -2599,6 +2711,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         target
       ));
 
+#ifndef SQLITE_OMIT_FLOATING_POINT
       /* If the column has REAL affinity, it may currently be stored as an
       ** integer. Use OP_RealAffinity to make sure it is really real.  */
       if( pExpr->iColumn>=0 
@@ -2606,6 +2719,7 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
       ){
         sqlite3VdbeAddOp1(v, OP_RealAffinity, target);
       }
+#endif
       break;
     }
 
@@ -2661,6 +2775,11 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         opCompare.op = TK_EQ;
         opCompare.pLeft = &cacheX;
         pTest = &opCompare;
+        /* Ticket b351d95f9cd5ef17e9d9dbae18f5ca8611190001:
+        ** The value in regFree1 might get SCopy-ed into the file result.
+        ** So make sure that the regFree1 register is not reused for other
+        ** purposes and possibly overwritten.  */
+        regFree1 = 0;
       }
       for(i=0; i<nExpr; i=i+2){
         sqlite3ExprCachePush(pParse);
@@ -2754,10 +2873,14 @@ int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
   int inReg;
 
   assert( target>0 && target<=pParse->nMem );
-  inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
-  assert( pParse->pVdbe || pParse->db->mallocFailed );
-  if( inReg!=target && pParse->pVdbe ){
-    sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+  if( pExpr && pExpr->op==TK_REGISTER ){
+    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Copy, pExpr->iTable, target);
+  }else{
+    inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
+    assert( pParse->pVdbe || pParse->db->mallocFailed );
+    if( inReg!=target && pParse->pVdbe ){
+      sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, inReg, target);
+    }
   }
   return target;
 }
@@ -2790,6 +2913,7 @@ int sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
     iMem = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_Copy, inReg, iMem);
     pExpr->iTable = iMem;
+    pExpr->op2 = pExpr->op;
     pExpr->op = TK_REGISTER;
   }
   return inReg;
@@ -2863,6 +2987,7 @@ static int isAppropriateForFactoring(Expr *p){
 static int evalConstExpr(Walker *pWalker, Expr *pExpr){
   Parse *pParse = pWalker->pParse;
   switch( pExpr->op ){
+    case TK_IN:
     case TK_REGISTER: {
       return WRC_Prune;
     }
@@ -2928,25 +3053,76 @@ int sqlite3ExprCodeExprList(
   int i, n;
   assert( pList!=0 );
   assert( target>0 );
+  assert( pParse->pVdbe!=0 );  /* Never gets this far otherwise */
   n = pList->nExpr;
   for(pItem=pList->a, i=0; i<n; i++, pItem++){
-    if( pItem->iAlias ){
-      int iReg = codeAlias(pParse, pItem->iAlias, pItem->pExpr, target+i);
-      Vdbe *v = sqlite3GetVdbe(pParse);
-      if( iReg!=target+i ){
-        sqlite3VdbeAddOp2(v, OP_SCopy, iReg, target+i);
-      }
-    }else{
-      sqlite3ExprCode(pParse, pItem->pExpr, target+i);
-    }
-    if( doHardCopy && !pParse->db->mallocFailed ){
-      sqlite3ExprHardCopy(pParse, target, n);
+    Expr *pExpr = pItem->pExpr;
+    int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
+    if( inReg!=target+i ){
+      sqlite3VdbeAddOp2(pParse->pVdbe, doHardCopy ? OP_Copy : OP_SCopy,
+                        inReg, target+i);
     }
   }
   return n;
 }
 
 /*
+** Generate code for a BETWEEN operator.
+**
+**    x BETWEEN y AND z
+**
+** The above is equivalent to 
+**
+**    x>=y AND x<=z
+**
+** Code it as such, taking care to do the common subexpression
+** elementation of x.
+*/
+static void exprCodeBetween(
+  Parse *pParse,    /* Parsing and code generating context */
+  Expr *pExpr,      /* The BETWEEN expression */
+  int dest,         /* Jump here if the jump is taken */
+  int jumpIfTrue,   /* Take the jump if the BETWEEN is true */
+  int jumpIfNull    /* Take the jump if the BETWEEN is NULL */
+){
+  Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
+  Expr compLeft;    /* The  x>=y  term */
+  Expr compRight;   /* The  x<=z  term */
+  Expr exprX;       /* The  x  subexpression */
+  int regFree1 = 0; /* Temporary use register */
+
+  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+  exprX = *pExpr->pLeft;
+  exprAnd.op = TK_AND;
+  exprAnd.pLeft = &compLeft;
+  exprAnd.pRight = &compRight;
+  compLeft.op = TK_GE;
+  compLeft.pLeft = &exprX;
+  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
+  compRight.op = TK_LE;
+  compRight.pLeft = &exprX;
+  compRight.pRight = pExpr->x.pList->a[1].pExpr;
+  exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
+  exprX.op = TK_REGISTER;
+  if( jumpIfTrue ){
+    sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+  }else{
+    sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+  }
+  sqlite3ReleaseTempReg(pParse, regFree1);
+
+  /* Ensure adequate test coverage */
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue==0 && jumpIfNull!=0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull==0 && regFree1!=0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1==0 );
+  testcase( jumpIfTrue!=0 && jumpIfNull!=0 && regFree1!=0 );
+}
+
+/*
 ** Generate code for a boolean expression such that a jump is made
 ** to the label "dest" if the expression is true but execution
 ** continues straight thru if the expression is false.
@@ -3012,14 +3188,27 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
       testcase( jumpIfNull==0 );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, dest, jumpIfNull);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( op==TK_IS );
+      testcase( op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (op==TK_IS) ? TK_EQ : TK_NE;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_ISNULL:
     case TK_NOTNULL: {
       assert( TK_ISNULL==OP_IsNull );
@@ -3032,36 +3221,16 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to 
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->x.pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->x.pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 1, jumpIfNull);
+      break;
+    }
+    case TK_IN: {
+      int destIfFalse = sqlite3VdbeMakeLabel(v);
+      int destIfNull = jumpIfNull ? dest : destIfFalse;
+      sqlite3ExprCodeIN(pParse, pExpr, destIfFalse, destIfNull);
+      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
+      sqlite3VdbeResolveLabel(v, destIfFalse);
       break;
     }
     default: {
@@ -3145,6 +3314,7 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       break;
     }
     case TK_NOT: {
+      testcase( jumpIfNull==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
       break;
     }
@@ -3161,14 +3331,27 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       testcase( op==TK_EQ );
       testcase( op==TK_NE );
       testcase( jumpIfNull==0 );
-      codeCompareOperands(pParse, pExpr->pLeft, &r1, &regFree1,
-                                  pExpr->pRight, &r2, &regFree2);
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                   r1, r2, dest, jumpIfNull);
       testcase( regFree1==0 );
       testcase( regFree2==0 );
       break;
     }
+    case TK_IS:
+    case TK_ISNOT: {
+      testcase( pExpr->op==TK_IS );
+      testcase( pExpr->op==TK_ISNOT );
+      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
+      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
+      op = (pExpr->op==TK_IS) ? TK_NE : TK_EQ;
+      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
+                  r1, r2, dest, SQLITE_NULLEQ);
+      testcase( regFree1==0 );
+      testcase( regFree2==0 );
+      break;
+    }
     case TK_ISNULL:
     case TK_NOTNULL: {
       testcase( op==TK_ISNULL );
@@ -3179,36 +3362,18 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       break;
     }
     case TK_BETWEEN: {
-      /*    x BETWEEN y AND z
-      **
-      ** Is equivalent to 
-      **
-      **    x>=y AND x<=z
-      **
-      ** Code it as such, taking care to do the common subexpression
-      ** elementation of x.
-      */
-      Expr exprAnd;
-      Expr compLeft;
-      Expr compRight;
-      Expr exprX;
-
-      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
-      exprX = *pExpr->pLeft;
-      exprAnd.op = TK_AND;
-      exprAnd.pLeft = &compLeft;
-      exprAnd.pRight = &compRight;
-      compLeft.op = TK_GE;
-      compLeft.pLeft = &exprX;
-      compLeft.pRight = pExpr->x.pList->a[0].pExpr;
-      compRight.op = TK_LE;
-      compRight.pLeft = &exprX;
-      compRight.pRight = pExpr->x.pList->a[1].pExpr;
-      exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-      testcase( regFree1==0 );
-      exprX.op = TK_REGISTER;
       testcase( jumpIfNull==0 );
-      sqlite3ExprIfFalse(pParse, &exprAnd, dest, jumpIfNull);
+      exprCodeBetween(pParse, pExpr, dest, 0, jumpIfNull);
+      break;
+    }
+    case TK_IN: {
+      if( jumpIfNull ){
+        sqlite3ExprCodeIN(pParse, pExpr, dest, dest);
+      }else{
+        int destIfNull = sqlite3VdbeMakeLabel(v);
+        sqlite3ExprCodeIN(pParse, pExpr, dest, destIfNull);
+        sqlite3VdbeResolveLabel(v, destIfNull);
+      }
       break;
     }
     default: {
@@ -3224,59 +3389,76 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
 }
 
 /*
-** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
-** if they are identical and return FALSE if they differ in any way.
+** Do a deep comparison of two expression trees.  Return 0 if the two
+** expressions are completely identical.  Return 1 if they differ only
+** by a COLLATE operator at the top level.  Return 2 if there are differences
+** other than the top-level COLLATE operator.
 **
-** Sometimes this routine will return FALSE even if the two expressions
+** Sometimes this routine will return 2 even if the two expressions
 ** really are equivalent.  If we cannot prove that the expressions are
-** identical, we return FALSE just to be safe.  So if this routine
-** returns false, then you do not really know for certain if the two
-** expressions are the same.  But if you get a TRUE return, then you
+** identical, we return 2 just to be safe.  So if this routine
+** returns 2, then you do not really know for certain if the two
+** expressions are the same.  But if you get a 0 or 1 return, then you
 ** can be sure the expressions are the same.  In the places where
-** this routine is used, it does not hurt to get an extra FALSE - that
+** this routine is used, it does not hurt to get an extra 2 - that
 ** just might result in some slightly slower code.  But returning
-** an incorrect TRUE could lead to a malfunction.
+** an incorrect 0 or 1 could lead to a malfunction.
 */
 int sqlite3ExprCompare(Expr *pA, Expr *pB){
-  int i;
   if( pA==0||pB==0 ){
-    return pB==pA;
+    return pB==pA ? 0 : 2;
   }
   assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
   assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
   if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
-    return 0;
-  }
-  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 0;
-  if( pA->op!=pB->op ) return 0;
-  if( !sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 0;
-  if( !sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 0;
-
-  if( pA->x.pList && pB->x.pList ){
-    if( pA->x.pList->nExpr!=pB->x.pList->nExpr ) return 0;
-    for(i=0; i<pA->x.pList->nExpr; i++){
-      Expr *pExprA = pA->x.pList->a[i].pExpr;
-      Expr *pExprB = pB->x.pList->a[i].pExpr;
-      if( !sqlite3ExprCompare(pExprA, pExprB) ) return 0;
-    }
-  }else if( pA->x.pList || pB->x.pList ){
-    return 0;
-  }
-
-  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 0;
+    return 2;
+  }
+  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
+  if( pA->op!=pB->op ) return 2;
+  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
+  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;
+  if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList) ) return 2;
+  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
   if( ExprHasProperty(pA, EP_IntValue) ){
     if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
-      return 0;
+      return 2;
     }
   }else if( pA->op!=TK_COLUMN && pA->u.zToken ){
-    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 0;
+    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
     if( sqlite3StrICmp(pA->u.zToken,pB->u.zToken)!=0 ){
-      return 0;
+      return 2;
     }
   }
-  return 1;
+  if( (pA->flags & EP_ExpCollate)!=(pB->flags & EP_ExpCollate) ) return 1;
+  if( (pA->flags & EP_ExpCollate)!=0 && pA->pColl!=pB->pColl ) return 2;
+  return 0;
 }
 
+/*
+** Compare two ExprList objects.  Return 0 if they are identical and 
+** non-zero if they differ in any way.
+**
+** This routine might return non-zero for equivalent ExprLists.  The
+** only consequence will be disabled optimizations.  But this routine
+** must never return 0 if the two ExprList objects are different, or
+** a malfunction will result.
+**
+** Two NULL pointers are considered to be the same.  But a NULL pointer
+** always differs from a non-NULL pointer.
+*/
+int sqlite3ExprListCompare(ExprList *pA, ExprList *pB){
+  int i;
+  if( pA==0 && pB==0 ) return 0;
+  if( pA==0 || pB==0 ) return 1;
+  if( pA->nExpr!=pB->nExpr ) return 1;
+  for(i=0; i<pA->nExpr; i++){
+    Expr *pExprA = pA->a[i].pExpr;
+    Expr *pExprB = pB->a[i].pExpr;
+    if( pA->a[i].sortOrder!=pB->a[i].sortOrder ) return 1;
+    if( sqlite3ExprCompare(pExprA, pExprB) ) return 1;
+  }
+  return 0;
+}
 
 /*
 ** Add a new element to the pAggInfo->aCol[] array.  Return the index of
@@ -3405,7 +3587,7 @@ static int analyzeAggregate(Walker *pWalker, Expr *pExpr){
         */
         struct AggInfo_func *pItem = pAggInfo->aFunc;
         for(i=0; i<pAggInfo->nFunc; i++, pItem++){
-          if( sqlite3ExprCompare(pItem->pExpr, pExpr) ){
+          if( sqlite3ExprCompare(pItem->pExpr, pExpr)==0 ){
             break;
           }
         }
@@ -3526,7 +3708,8 @@ int sqlite3GetTempRange(Parse *pParse, int nReg){
   int i, n;
   i = pParse->iRangeReg;
   n = pParse->nRangeReg;
-  if( nReg<=n && !usedAsColumnCache(pParse, i, i+n-1) ){
+  if( nReg<=n ){
+    assert( !usedAsColumnCache(pParse, i, i+n-1) );
     pParse->iRangeReg += nReg;
     pParse->nRangeReg -= nReg;
   }else{
@@ -3536,6 +3719,7 @@ int sqlite3GetTempRange(Parse *pParse, int nReg){
   return i;
 }
 void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
+  sqlite3ExprCacheRemove(pParse, iReg, nReg);
   if( nReg>pParse->nRangeReg ){
     pParse->nRangeReg = nReg;
     pParse->iRangeReg = iReg;