Clean up the implementation of constant function factorization.
FossilOrigin-Name: 2ab997e47998d261bd6190bbce5c09f3fbd4cfd3
diff --git a/src/expr.c b/src/expr.c
index 2fb5dff..d6133c0 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3613,7 +3613,9 @@
CollSeq *pColl = 0; /* A collating sequence */
if( ConstFactorOk(pParse) && sqlite3ExprIsConstantNotJoin(pExpr) ){
- return sqlite3ExprCodeAtInit(pParse, pExpr, -1, 1);
+ /* SQL function can be expensive. So try to move constant functions
+ ** out of the inner loop, even if that means an extra OP_Copy. */
+ return sqlite3ExprCodeAtInit(pParse, pExpr, -1);
}
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
if( ExprHasProperty(pExpr, EP_TokenOnly) ){
@@ -3996,41 +3998,36 @@
/*
** Factor out the code of the given expression to initialization time.
**
-** If regDest>=0 then the result is always stored in that register.
-** If regDest<0 then this routine is free to store the value whereever
-** it wants. The register where the expression is stored is returned.
-**
-** If regDest<0 and an equivalent expression already exists elsewhere
-** in the initialization expressions, then routine just returns the
-** register of the prior occurrance.
+** If regDest>=0 then the result is always stored in that register and the
+** result is not reusable. If regDest<0 then this routine is free to
+** store the value whereever it wants. The register where the expression
+** is stored is returned. When regDest<0, two identical expressions will
+** code to the same register.
*/
int sqlite3ExprCodeAtInit(
Parse *pParse, /* Parsing context */
Expr *pExpr, /* The expression to code when the VDBE initializes */
- int regDest, /* Store the value in this register */
- u8 reusable /* True if this expression is reusable */
+ int regDest /* Store the value in this register */
){
ExprList *p;
assert( ConstFactorOk(pParse) );
p = pParse->pConstExpr;
- if( regDest<0 ){
- if( p && reusable ){
- struct ExprList_item *pItem;
- int i;
- for(pItem=p->a, i=p->nExpr; i>0; pItem++, i--){
- if( pItem->reusable && sqlite3ExprCompare(pItem->pExpr,pExpr,-1)==0 ){
- return pItem->u.iConstExprReg;
- }
+ if( regDest<0 && p ){
+ struct ExprList_item *pItem;
+ int i;
+ for(pItem=p->a, i=p->nExpr; i>0; pItem++, i--){
+ if( pItem->reusable && sqlite3ExprCompare(pItem->pExpr,pExpr,-1)==0 ){
+ return pItem->u.iConstExprReg;
}
}
- regDest = ++pParse->nMem;
}
pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
p = sqlite3ExprListAppend(pParse, p, pExpr);
if( p ){
struct ExprList_item *pItem = &p->a[p->nExpr-1];
+ pItem->reusable = regDest<0;
+ if( regDest<0 ) regDest = ++pParse->nMem;
pItem->u.iConstExprReg = regDest;
- pItem->reusable = reusable;
}
pParse->pConstExpr = p;
return regDest;
@@ -4057,7 +4054,7 @@
&& sqlite3ExprIsConstantNotJoin(pExpr)
){
*pReg = 0;
- r2 = sqlite3ExprCodeAtInit(pParse, pExpr, -1, 1);
+ r2 = sqlite3ExprCodeAtInit(pParse, pExpr, -1);
}else{
int r1 = sqlite3GetTempReg(pParse);
r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
@@ -4111,7 +4108,7 @@
*/
void sqlite3ExprCodeFactorable(Parse *pParse, Expr *pExpr, int target){
if( pParse->okConstFactor && sqlite3ExprIsConstant(pExpr) ){
- sqlite3ExprCodeAtInit(pParse, pExpr, target, 0);
+ sqlite3ExprCodeAtInit(pParse, pExpr, target);
}else{
sqlite3ExprCode(pParse, pExpr, target);
}
@@ -4183,7 +4180,7 @@
sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
}
}else if( (flags & SQLITE_ECEL_FACTOR)!=0 && sqlite3ExprIsConstant(pExpr) ){
- sqlite3ExprCodeAtInit(pParse, pExpr, target+i, 0);
+ sqlite3ExprCodeAtInit(pParse, pExpr, target+i);
}else{
int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target+i);
if( inReg!=target+i ){