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Add in expr optimization at the parser level instead of translation.

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lhs IN () and lhs NOT IN () can be translated to false and true.
This commit is contained in:
Diego Reis
2025-10-06 21:34:54 -03:00
parent 70fc509046
commit 52ed0f7997
2 changed files with 17 additions and 14 deletions
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9
core/translate/expr.rs
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@@ -191,15 +191,6 @@ fn translate_in_list(
dest_if_null: BranchOffset,
resolver: &Resolver,
) -> Result<()> {
// Disclamer: SQLite does this opt during parsing (https://github.com/sqlite/sqlite/blob/833fb1ef59b1c62fb2b00c7a121a5b5171f8a85e/src/parse.y#L1425)
// But we're the cool kids so we gotta do during translation :)
if rhs.is_empty() {
program.emit_insn(Insn::Goto {
target_pc: dest_if_false,
});
return Ok(());
}
let lhs_reg = expr_code_vector(program, lhs);
let _ = translate_expr(program, referenced_tables, lhs, lhs_reg, resolver)?;
let mut check_null_reg = 0;

22
parser/src/parser.rs
View File

@@ -1723,11 +1723,23 @@ impl<'a> Parser<'a> {
_ => {
let exprs = self.parse_expr_list()?;
eat_expect!(self, TK_RP);
Box::new(Expr::InList {
lhs: result,
not,
rhs: exprs,
})
// Expressions in the form:
// lhs IN ()
// lhs NOT IN ()
// can be simplified to constants 0 (false) and 1 (true), respectively.
//
// todo: should check if lhs has a function. If so, this optimization cannot
// be done.
if exprs.is_empty() {
let name = if not { "1" } else { "0" };
Box::new(Expr::Literal(Literal::Numeric(name.into())))
} else {
Box::new(Expr::InList {
lhs: result,
not,
rhs: exprs,
})
}
}
}
}