1 files changed, 36 insertions, 17 deletions

diff --git a/src/expr.c b/src/expr.c
index 82623b14b..e5d8a6129 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -70,7 +70,7 @@ Expr *sqlite3ExprAddCollateToken(Parse *pParse, Expr *pExpr, Token *pCollName){
     Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, 1);
     if( pNew ){
       pNew->pLeft = pExpr;
-      pNew->flags |= EP_Collate;
+      pNew->flags |= EP_Collate|EP_Skip;
       pExpr = pNew;
     }
   }
@@ -85,13 +85,21 @@ Expr *sqlite3ExprAddCollateString(Parse *pParse, Expr *pExpr, const char *zC){
 }
 
 /*
-** Skip over any TK_COLLATE and/or TK_AS operators at the root of
-** an expression.
+** Skip over any TK_COLLATE or TK_AS operators and any unlikely()
+** or likelihood() function at the root of an expression.
 */
 Expr *sqlite3ExprSkipCollate(Expr *pExpr){
-  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
-    pExpr = pExpr->pLeft;
-  }
+  while( pExpr && ExprHasProperty(pExpr, EP_Skip) ){
+    if( ExprHasProperty(pExpr, EP_Unlikely) ){
+      assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
+      assert( pExpr->x.pList->nExpr>0 );
+      assert( pExpr->op==TK_FUNCTION );
+      pExpr = pExpr->x.pList->a[0].pExpr;
+    }else{
+      assert( pExpr->op==TK_COLLATE || pExpr->op==TK_AS );
+      pExpr = pExpr->pLeft;
+    }
+  }   
   return pExpr;
 }
 
@@ -2316,6 +2324,16 @@ static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
 #endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
 
 /*
+** Convert an expression node to a TK_REGISTER
+*/
+static void exprToRegister(Expr *p, int iReg){
+  p->op2 = p->op;
+  p->op = TK_REGISTER;
+  p->iTable = iReg;
+  ExprClearProperty(p, EP_Skip);
+}
+
+/*
 ** Generate code into the current Vdbe to evaluate the given
 ** expression.  Attempt to store the results in register "target".
 ** Return the register where results are stored.
@@ -2648,6 +2666,14 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         break;
       }
 
+      /* The UNLIKELY() function is a no-op.  The result is the value
+      ** of the first argument.
+      */
+      if( pDef->funcFlags & SQLITE_FUNC_UNLIKELY ){
+        assert( nFarg>=1 );
+        sqlite3ExprCode(pParse, pFarg->a[0].pExpr, target);
+        break;
+      }
 
       if( pFarg ){
         r1 = sqlite3GetTempRange(pParse, nFarg);
@@ -2877,9 +2903,8 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
         cacheX = *pX;
         testcase( pX->op==TK_COLUMN );
         testcase( pX->op==TK_REGISTER );
-        cacheX.iTable = sqlite3ExprCodeTemp(pParse, pX, &regFree1);
+        exprToRegister(&cacheX, sqlite3ExprCodeTemp(pParse, pX, &regFree1));
         testcase( regFree1==0 );
-        cacheX.op = TK_REGISTER;
         opCompare.op = TK_EQ;
         opCompare.pLeft = &cacheX;
         pTest = &opCompare;
@@ -3021,9 +3046,7 @@ int sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr, int target){
     int iMem;
     iMem = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_Copy, inReg, iMem);
-    pExpr->iTable = iMem;
-    pExpr->op2 = pExpr->op;
-    pExpr->op = TK_REGISTER;
+    exprToRegister(pExpr, iMem);
   }
   return inReg;
 }
@@ -3402,9 +3425,7 @@ static int evalConstExpr(Walker *pWalker, Expr *pExpr){
     ** but suboptimal, so we want to know about the situation to fix it.
     ** Hence the following assert: */
     assert( r2==r1 );
-    pExpr->op2 = pExpr->op;
-    pExpr->op = TK_REGISTER;
-    pExpr->iTable = r2;
+    exprToRegister(pExpr, r2);
     return WRC_Prune;
   }
   return WRC_Continue;
@@ -3502,9 +3523,7 @@ static void exprCodeBetween(
   compRight.op = TK_LE;
   compRight.pLeft = &exprX;
   compRight.pRight = pExpr->x.pList->a[1].pExpr;
-  exprX.iTable = sqlite3ExprCodeTemp(pParse, &exprX, &regFree1);
-  exprX.op2 = exprX.op;
-  exprX.op = TK_REGISTER;
+  exprToRegister(&exprX, sqlite3ExprCodeTemp(pParse, &exprX, &regFree1));
   if( jumpIfTrue ){
     sqlite3ExprIfTrue(pParse, &exprAnd, dest, jumpIfNull);
   }else{