Index: src/expr.c ================================================================== --- src/expr.c +++ src/expr.c @@ -521,20 +521,29 @@ } return p; } /* -** Return 1 if an expression must be FALSE in all cases and 0 if the -** expression might be true. This is an optimization. If is OK to -** return 0 here even if the expression really is always false (a -** false negative). But it is a bug to return 1 if the expression -** might be true in some rare circumstances (a false positive.) +** If the expression is always either TRUE or FALSE (respectively), +** then return 1. If one cannot determine the truth value of the +** expression at compile-time return 0. +** +** This is an optimization. If is OK to return 0 here even if +** the expression really is always false or false (a false negative). +** But it is a bug to return 1 if the expression might have different +** boolean values in different circumstances (a false positive.) ** ** Note that if the expression is part of conditional for a ** LEFT JOIN, then we cannot determine at compile-time whether or not ** is it true or false, so always return 0. */ +static int exprAlwaysTrue(Expr *p){ + int v = 0; + if( ExprHasProperty(p, EP_FromJoin) ) return 0; + if( !sqlite3ExprIsInteger(p, &v) ) return 0; + return v!=0; +} static int exprAlwaysFalse(Expr *p){ int v = 0; if( ExprHasProperty(p, EP_FromJoin) ) return 0; if( !sqlite3ExprIsInteger(p, &v) ) return 0; return v==0; @@ -3612,14 +3621,20 @@ sqlite3VdbeResolveLabel(v, destIfFalse); break; } #endif default: { - r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1); - sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0); - testcase( regFree1==0 ); - testcase( jumpIfNull==0 ); + if( exprAlwaysTrue(pExpr) ){ + sqlite3VdbeAddOp2(v, OP_Goto, 0, dest); + }else if( exprAlwaysFalse(pExpr) ){ + /* No-op */ + }else{ + r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1); + sqlite3VdbeAddOp3(v, OP_If, r1, dest, jumpIfNull!=0); + testcase( regFree1==0 ); + testcase( jumpIfNull==0 ); + } break; } } sqlite3ReleaseTempReg(pParse, regFree1); sqlite3ReleaseTempReg(pParse, regFree2); @@ -3757,14 +3772,20 @@ } break; } #endif default: { - r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1); - sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0); - testcase( regFree1==0 ); - testcase( jumpIfNull==0 ); + if( exprAlwaysFalse(pExpr) ){ + sqlite3VdbeAddOp2(v, OP_Goto, 0, dest); + }else if( exprAlwaysTrue(pExpr) ){ + /* no-op */ + }else{ + r1 = sqlite3ExprCodeTemp(pParse, pExpr, ®Free1); + sqlite3VdbeAddOp3(v, OP_IfNot, r1, dest, jumpIfNull!=0); + testcase( regFree1==0 ); + testcase( jumpIfNull==0 ); + } break; } } sqlite3ReleaseTempReg(pParse, regFree1); sqlite3ReleaseTempReg(pParse, regFree2);