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Add a count parameter to the OP_Variable opcode and use it to simplify

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prepared statements that copy consecutive unnamed parameters into
consecutive registers (a common case). (CVS 6309)

FossilOrigin-Name: 48b77b04935d8942eb22f0c061f3bc5e99bbd7db
This commit is contained in:
drh
2009-02-20 03:55:05 +00:00
parent 5053a79b6c
commit 08de14908d
6 changed files with 129 additions and 32 deletions
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25
src/expr.c
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@@ -12,7 +12,7 @@
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.412 2009/02/19 14:39:25 danielk1977 Exp $
** $Id: expr.c,v 1.413 2009/02/20 03:55:05 drh Exp $
*/
#include "sqliteInt.h"
@@ -2002,9 +2002,26 @@ int sqlite3ExprCodeTarget(Parse *pParse, Expr *pExpr, int target){
}
#endif
case TK_VARIABLE: {
sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iTable, target);
if( pExpr->token.n>1 ){
sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
int iPrior;
VdbeOp *pOp;
if( pExpr->token.n<=1
&& (iPrior = sqlite3VdbeCurrentAddr(v)-1)>=0
&& (pOp = sqlite3VdbeGetOp(v, iPrior))->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->token.n>1 ){
sqlite3VdbeChangeP4(v, -1, (char*)pExpr->token.z, pExpr->token.n);
}
}
break;
}