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Factor constant subexpressions out of loops. (CVS 4942)

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FossilOrigin-Name: 2126db39854c751aea6c95c67894ed9b9dfc0763
This commit is contained in:
drh
2008-03-31 18:19:54 +00:00
parent a686bfcfa5
commit 678ccce8b3
6 changed files with 92 additions and 42 deletions
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32
src/where.c
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@@ -16,7 +16,7 @@
** so is applicable. Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.294 2008/03/28 19:16:57 danielk1977 Exp $
** $Id: where.c,v 1.295 2008/03/31 18:19:54 drh Exp $
*/
#include "sqliteInt.h"
@@ -535,7 +535,8 @@ static int isLikeOrGlob(
#endif
pList = pExpr->pList;
pRight = pList->a[0].pExpr;
if( pRight->op!=TK_STRING ){
if( pRight->op!=TK_STRING
&& (pRight->op!=TK_REGISTER || pRight->iColumn!=TK_STRING) ){
return 0;
}
pLeft = pList->a[1].pExpr;
@@ -1752,19 +1753,23 @@ static void buildIndexProbe(
** result is left on the stack. For constraints of the form X IN (...)
** this routine sets up a loop that will iterate over all values of X.
*/
static void codeEqualityTerm(
static int codeEqualityTerm(
Parse *pParse, /* The parsing context */
WhereTerm *pTerm, /* The term of the WHERE clause to be coded */
WhereLevel *pLevel, /* When level of the FROM clause we are working on */
int iReg /* Leave results in this register */
int iTarget /* Attempt to leave results in this register */
){
Expr *pX = pTerm->pExpr;
Vdbe *v = pParse->pVdbe;
int iReg; /* Register holding results */
assert( iReg>0 && iReg<=pParse->nMem );
if( iTarget<=0 ){
iReg = iTarget = sqlite3GetTempReg(pParse);
}
if( pX->op==TK_EQ ){
sqlite3ExprCode(pParse, pX->pRight, iReg);
iReg = sqlite3ExprCodeTarget(pParse, pX->pRight, iTarget);
}else if( pX->op==TK_ISNULL ){
iReg = iTarget;
sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE_OMIT_SUBQUERY
}else{
@@ -1773,6 +1778,7 @@ static void codeEqualityTerm(
struct InLoop *pIn;
assert( pX->op==TK_IN );
iReg = iTarget;
eType = sqlite3FindInIndex(pParse, pX, 1);
iTab = pX->iTable;
sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
@@ -1799,6 +1805,7 @@ static void codeEqualityTerm(
#endif
}
disableTerm(pLevel, pTerm);
return iReg;
}
/*
@@ -1852,11 +1859,15 @@ static int codeAllEqualityTerms(
*/
assert( pIdx->nColumn>=nEq );
for(j=0; j<nEq; j++){
int r1;
int k = pIdx->aiColumn[j];
pTerm = findTerm(pWC, iCur, k, notReady, pLevel->flags, pIdx);
if( pTerm==0 ) break;
assert( (pTerm->flags & TERM_CODED)==0 );
codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
if( r1!=regBase+j ){
sqlite3VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
}
if( (pTerm->eOperator & (WO_ISNULL|WO_IN))==0 ){
sqlite3VdbeAddOp2(v, OP_IsNull, regBase+j, pLevel->brk);
}
@@ -2022,6 +2033,7 @@ WhereInfo *sqlite3WhereBegin(
*/
initMaskSet(&maskSet);
whereClauseInit(&wc, pParse, &maskSet);
sqlite3ExprCodeConstants(pParse, pWhere);
whereSplit(&wc, pWhere, TK_AND);
/* Allocate and initialize the WhereInfo structure that will become the
@@ -2367,13 +2379,11 @@ WhereInfo *sqlite3WhereBegin(
assert( pTerm->pExpr!=0 );
assert( pTerm->leftCursor==iCur );
assert( omitTable==0 );
r1 = sqlite3GetTempReg(pParse);
codeEqualityTerm(pParse, pTerm, pLevel, r1);
r1 = codeEqualityTerm(pParse, pTerm, pLevel, 0);
nxt = pLevel->nxt;
sqlite3VdbeAddOp3(v, OP_MustBeInt, r1, nxt, 1);
sqlite3VdbeAddOp2(v, OP_MustBeInt, r1, nxt);
sqlite3VdbeAddOp3(v, OP_NotExists, iCur, nxt, r1);
VdbeComment((v, "pk"));
sqlite3ReleaseTempReg(pParse, r1);
pLevel->op = OP_Noop;
}else if( pLevel->flags & WHERE_ROWID_RANGE ){
/* Case 2: We have an inequality comparison against the ROWID field.