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Overview
| Comment: | The docs promise the in "x BETWEEN y AND z" the x expression is only evaluated once. That is no longer true, and so some tests are failing. This needs to be fixed before merging to trunk. |
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| Timelines: | family | ancestors | descendants | both | rowvalue |
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| SHA1: |
e50d264fdc2f08d19202c68f73f18df3 |
| User & Date: | drh 2016-08-20 22:49:28 |
Context
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2016-08-22
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| 00:48 | Reinstate the mechanism in BETWEEN that avoids evaluating the first expression more than once, but fix the affinity extractor so that it works with this mechanism. The de-duplication of the first expression still does not work for vector expressions, though. check-in: 2f39987f user: drh tags: rowvalue | |
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2016-08-20
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| 22:49 | The docs promise the in "x BETWEEN y AND z" the x expression is only evaluated once. That is no longer true, and so some tests are failing. This needs to be fixed before merging to trunk. check-in: e50d264f user: drh tags: rowvalue | |
| 21:11 | Further comment enhancements. No changes to code. check-in: d4562a9e user: drh tags: rowvalue | |
Changes
Changes to src/expr.c.
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** ** The above is equivalent to ** ** x>=y AND x<=z ** ** Code it as such, taking care to do the common subexpression ** elimination 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 */ void (*xJumpIf)(Parse*,Expr*,int,int), 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 */ memset(&compLeft, 0, sizeof(Expr)); memset(&compRight, 0, sizeof(Expr)); memset(&exprAnd, 0, sizeof(Expr)); 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; if( sqlite3ExprIsVector(&exprX)==0 ){ exprToRegister(&exprX, sqlite3ExprCodeTemp(pParse, &exprX, ®Free1)); } if( xJumpIf ){ xJumpIf(pParse, &exprAnd, dest, jumpIfNull); }else{ exprX.flags |= EP_FromJoin; sqlite3ExprCodeTarget(pParse, &exprAnd, dest); } 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. ** |
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** ** The above is equivalent to ** ** x>=y AND x<=z ** ** Code it as such, taking care to do the common subexpression ** elimination of x. ** ** The xJumpIf parameter determines details: ** ** NULL: Store the boolean result in reg[dest] ** sqlite3ExprIfTrue: Jump to dest if true ** sqlite3ExprIfFalse: Jump to dest if false ** ** The jumpIfNull parameter is ignored if xJumpIf is NULL. */ static void exprCodeBetween( Parse *pParse, /* Parsing and code generating context */ Expr *pExpr, /* The BETWEEN expression */ int dest, /* Jump destination or storage location */ void (*xJump)(Parse*,Expr*,int,int), /* Action to take */ 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 */ assert( xJump==0 || xJump==sqlite3ExprIfTrue || xJump==sqlite3ExprIfFalse ); assert( !ExprHasProperty(pExpr, EP_xIsSelect) ); memset(&compLeft, 0, sizeof(Expr)); memset(&compRight, 0, sizeof(Expr)); memset(&exprAnd, 0, sizeof(Expr)); exprAnd.op = TK_AND; exprAnd.pLeft = &compLeft; exprAnd.pRight = &compRight; compLeft.op = TK_GE; compLeft.pLeft = pExpr->pLeft; compLeft.pRight = pExpr->x.pList->a[0].pExpr; compRight.op = TK_LE; compRight.pLeft = pExpr->pLeft; compRight.pRight = pExpr->x.pList->a[1].pExpr; if( xJump ){ xJump(pParse, &exprAnd, dest, jumpIfNull); }else{ /*exprX.flags |= EP_FromJoin;*/ sqlite3ExprCodeTarget(pParse, &exprAnd, dest); } /* Ensure adequate test coverage */ testcase( xJump==sqlite3ExprIfTrue && jumpIfNull==0 ); testcase( xJump==sqlite3ExprIfTrue && jumpIfNull!=0 ); testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 ); testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 ); testcase( xJump==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. ** |