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feat: add the similar optimization function for bitwise negative #5516

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Merged
alamb merged 5 commits into from
Mar 15, 2023
Merged

feat: add the similar optimization function for bitwise negative #5516

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d025389
feat: add the similar optimization function for bitwise negative
izveigor Mar 8, 2023
e1d8e27
fix: some feature fixes
izveigor Mar 8, 2023
c1922e7
Merge branch 'main' into negative_clause
izveigor Mar 11, 2023
97f9246
fix: change name from "negative_clause" to "distribute_negation"
izveigor Mar 11, 2023
133f566
feat: add tests for De Morgan's laws
izveigor Mar 11, 2023
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41 changes: 36 additions & 5 deletions datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1002,6 +1002,11 @@ impl<'a, S: SimplifyInfo> ExprRewriter for Simplifier<'a, S> {
//
Expr::Not(inner) => negate_clause(*inner),

//
// Rules for Negative
//
Expr::Negative(inner) => distribute_negation(*inner),

//
// Rules for Case
//
Expand Down Expand Up @@ -2122,6 +2127,37 @@ mod tests {
assert_eq!(simplify(expr), expected);
}

#[test]
fn test_simplify_by_de_morgan_laws() {
// Laws with logical operations
// !(c3 AND c4) --> !c3 OR !c4
let expr = and(col("c3"), col("c4")).not();
let expected = or(col("c3").not(), col("c4").not());
assert_eq!(simplify(expr), expected);
// !(c3 OR c4) --> !c3 AND !c4
let expr = or(col("c3"), col("c4")).not();
let expected = and(col("c3").not(), col("c4").not());
assert_eq!(simplify(expr), expected);
// !(!c3) --> c3
let expr = col("c3").not().not();
let expected = col("c3");
assert_eq!(simplify(expr), expected);

// Laws with bitwise operations
// !(c3 & c4) --> !c3 | !c4
let expr = -bitwise_and(col("c3"), col("c4"));
let expected = bitwise_or(-col("c3"), -col("c4"));
assert_eq!(simplify(expr), expected);
// !(c3 | c4) --> !c3 & !c4
let expr = -bitwise_or(col("c3"), col("c4"));
let expected = bitwise_and(-col("c3"), -col("c4"));
assert_eq!(simplify(expr), expected);
// !(!c3) --> c3
let expr = -(-col("c3"));
let expected = col("c3");
assert_eq!(simplify(expr), expected);
}

#[test]
fn test_simplify_null_and_false() {
let expr = and(lit_bool_null(), lit(false));
Expand Down Expand Up @@ -2425,11 +2461,6 @@ mod tests {
)
}

#[test]
fn simplify_expr_not_not() {
assert_eq!(simplify(col("c2").not().not().not()), col("c2").not(),);
}

#[test]
fn simplify_expr_null_comparison() {
// x = null is always null
Expand Down
41 changes: 40 additions & 1 deletion datafusion/optimizer/src/simplify_expressions/utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@
use datafusion_common::{DataFusionError, Result, ScalarValue};
use datafusion_expr::{
expr::{Between, BinaryExpr},
expr_fn::{and, concat_ws, or},
expr_fn::{and, bitwise_and, bitwise_or, concat_ws, or},
lit, BuiltinScalarFunction, Expr, Like, Operator,
};

Expand Down Expand Up @@ -311,6 +311,45 @@ pub fn negate_clause(expr: Expr) -> Expr {
}
}

/// bitwise negate a Negative clause
/// input is the clause to be bitwise negated.(args for Negative clause)
/// For BinaryExpr:
/// ~(A & B) ===> ~A | ~B
/// ~(A | B) ===> ~A & ~B
/// For Negative:
/// ~(~A) ===> A
/// For others, use Negative clause
pub fn distribute_negation(expr: Expr) -> Expr {
match expr {
Expr::BinaryExpr(BinaryExpr { left, op, right }) => {
match op {
// ~(A & B) ===> ~A | ~B
Operator::BitwiseAnd => {
let left = distribute_negation(*left);
let right = distribute_negation(*right);

bitwise_or(left, right)
}
// ~(A | B) ===> ~A & ~B
Operator::BitwiseOr => {
let left = distribute_negation(*left);
let right = distribute_negation(*right);

bitwise_and(left, right)
}
// use negative clause
_ => Expr::Negative(Box::new(Expr::BinaryExpr(BinaryExpr::new(
left, op, right,
)))),
}
}
// ~(~A) ===> A
Expr::Negative(expr) => *expr,
// use negative clause
_ => Expr::Negative(Box::new(expr)),
}
}

/// Simplify the `concat` function by
/// 1. filtering out all `null` literals
/// 2. concatenating contiguous literal arguments
Expand Down