fix: Enable CSE in eager if struct are expanded (pola-rs#18426)

crates/polars-plan/src/frame/opt_state.rs

@@ -18,11 +18,9 @@ bitflags! {
         const FILE_CACHING = 1 << 6;
         /// Pushdown slices/limits.
         const SLICE_PUSHDOWN = 1 << 7;
-        #[cfg(feature = "cse")]
         /// Run common-subplan-elimination. This elides duplicate plans and caches their
         /// outputs.
         const COMM_SUBPLAN_ELIM = 1 << 8;
-        #[cfg(feature = "cse")]
         /// Run common-subexpression-elimination. This elides duplicate expressions and caches their
         /// outputs.
         const COMM_SUBEXPR_ELIM = 1 << 9;

crates/polars-plan/src/plans/conversion/dsl_to_ir.rs

@@ -20,9 +20,10 @@ fn expand_expressions(
     exprs: Vec<Expr>,
     lp_arena: &Arena<IR>,
     expr_arena: &mut Arena<AExpr>,
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<Vec<ExprIR>> {
     let schema = lp_arena.get(input).schema(lp_arena);
-    let exprs = rewrite_projections(exprs, &schema, &[])?;
+    let exprs = rewrite_projections(exprs, &schema, &[], opt_flags)?;
     to_expr_irs(exprs, expr_arena)
 }
 
@@ -57,17 +58,18 @@ pub fn to_alp(
     expr_arena: &mut Arena<AExpr>,
     lp_arena: &mut Arena<IR>,
     // Only `SIMPLIFY_EXPR` and `TYPE_COERCION` are respected.
-    opt_state: &mut OptFlags,
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<Node> {
     let conversion_optimizer = ConversionOptimizer::new(
-        opt_state.contains(OptFlags::SIMPLIFY_EXPR),
-        opt_state.contains(OptFlags::TYPE_COERCION),
+        opt_flags.contains(OptFlags::SIMPLIFY_EXPR),
+        opt_flags.contains(OptFlags::TYPE_COERCION),
     );
 
     let mut ctxt = ConversionContext {
         expr_arena,
         lp_arena,
         conversion_optimizer,
+        opt_flags,
     };
 
     to_alp_impl(lp, &mut ctxt)
@@ -77,6 +79,7 @@ struct ConversionContext<'a> {
     expr_arena: &'a mut Arena<AExpr>,
     lp_arena: &'a mut Arena<IR>,
     conversion_optimizer: ConversionOptimizer,
+    opt_flags: &'a mut OptFlags,
 }
 
 /// converts LogicalPlan to IR
@@ -305,7 +308,7 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
         DslPlan::Filter { input, predicate } => {
             let mut input =
                 to_alp_impl(owned(input), ctxt).map_err(|e| e.context(failed_input!(filter)))?;
-            let predicate = expand_filter(predicate, input, ctxt.lp_arena)
+            let predicate = expand_filter(predicate, input, ctxt.lp_arena, ctxt.opt_flags)
                 .map_err(|e| e.context(failed_here!(filter)))?;
 
             let predicate_ae = to_expr_ir(predicate.clone(), ctxt.expr_arena)?;
@@ -378,8 +381,8 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
             let input =
                 to_alp_impl(owned(input), ctxt).map_err(|e| e.context(failed_input!(select)))?;
             let schema = ctxt.lp_arena.get(input).schema(ctxt.lp_arena);
-            let (exprs, schema) =
-                prepare_projection(expr, &schema).map_err(|e| e.context(failed_here!(select)))?;
+            let (exprs, schema) = prepare_projection(expr, &schema, ctxt.opt_flags)
+                .map_err(|e| e.context(failed_here!(select)))?;
 
             if exprs.is_empty() {
                 ctxt.lp_arena.replace(input, empty_df());
@@ -442,8 +445,14 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
                     .cycle()
                     .zip(sort_options.descending.iter().cycle()),
             ) {
-                let exprs = expand_expressions(input, vec![c], ctxt.lp_arena, ctxt.expr_arena)
-                    .map_err(|e| e.context(failed_here!(sort)))?;
+                let exprs = expand_expressions(
+                    input,
+                    vec![c],
+                    ctxt.lp_arena,
+                    ctxt.expr_arena,
+                    ctxt.opt_flags,
+                )
+                .map_err(|e| e.context(failed_here!(sort)))?;
 
                 nulls_last.extend(std::iter::repeat(n).take(exprs.len()));
                 descending.extend(std::iter::repeat(d).take(exprs.len()));
@@ -489,9 +498,16 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
             let input =
                 to_alp_impl(owned(input), ctxt).map_err(|e| e.context(failed_input!(group_by)))?;
 
-            let (keys, aggs, schema) =
-                resolve_group_by(input, keys, aggs, &options, ctxt.lp_arena, ctxt.expr_arena)
-                    .map_err(|e| e.context(failed_here!(group_by)))?;
+            let (keys, aggs, schema) = resolve_group_by(
+                input,
+                keys,
+                aggs,
+                &options,
+                ctxt.lp_arena,
+                ctxt.expr_arena,
+                ctxt.opt_flags,
+            )
+            .map_err(|e| e.context(failed_here!(group_by)))?;
 
             let (apply, schema) = if let Some((apply, schema)) = apply {
                 (Some(apply), schema)
@@ -614,7 +630,7 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
             let input = to_alp_impl(owned(input), ctxt)
                 .map_err(|e| e.context(failed_input!(with_columns)))?;
             let (exprs, schema) =
-                resolve_with_columns(exprs, input, ctxt.lp_arena, ctxt.expr_arena)
+                resolve_with_columns(exprs, input, ctxt.lp_arena, ctxt.expr_arena, ctxt.opt_flags)
                     .map_err(|e| e.context(failed_here!(with_columns)))?;
 
             ctxt.conversion_optimizer
@@ -680,9 +696,14 @@ pub fn to_alp_impl(lp: DslPlan, ctxt: &mut ConversionContext) -> PolarsResult<No
                         })
                         .collect::<Vec<_>>();
 
-                    let (exprs, schema) =
-                        resolve_with_columns(exprs, input, ctxt.lp_arena, ctxt.expr_arena)
-                            .map_err(|e| e.context(failed_here!(fill_nan)))?;
+                    let (exprs, schema) = resolve_with_columns(
+                        exprs,
+                        input,
+                        ctxt.lp_arena,
+                        ctxt.expr_arena,
+                        ctxt.opt_flags,
+                    )
+                    .map_err(|e| e.context(failed_here!(fill_nan)))?;
 
                     ctxt.conversion_optimizer
                         .fill_scratch(&exprs, ctxt.expr_arena);
@@ -911,7 +932,12 @@ fn expand_scan_paths_with_hive_update(
     Ok(expanded_paths)
 }
 
-fn expand_filter(predicate: Expr, input: Node, lp_arena: &Arena<IR>) -> PolarsResult<Expr> {
+fn expand_filter(
+    predicate: Expr,
+    input: Node,
+    lp_arena: &Arena<IR>,
+    opt_flags: &mut OptFlags,
+) -> PolarsResult<Expr> {
     let schema = lp_arena.get(input).schema(lp_arena);
     let predicate = if has_expr(&predicate, |e| match e {
         Expr::Column(name) => is_regex_projection(name),
@@ -924,7 +950,7 @@ fn expand_filter(predicate: Expr, input: Node, lp_arena: &Arena<IR>) -> PolarsRe
         | Expr::Nth(_) => true,
         _ => false,
     }) {
-        let mut rewritten = rewrite_projections(vec![predicate], &schema, &[])?;
+        let mut rewritten = rewrite_projections(vec![predicate], &schema, &[], opt_flags)?;
         match rewritten.len() {
             1 => {
                 // all good
@@ -971,10 +997,11 @@ fn resolve_with_columns(
     input: Node,
     lp_arena: &Arena<IR>,
     expr_arena: &mut Arena<AExpr>,
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<(Vec<ExprIR>, SchemaRef)> {
     let schema = lp_arena.get(input).schema(lp_arena);
     let mut new_schema = (**schema).clone();
-    let (exprs, _) = prepare_projection(exprs, &schema)?;
+    let (exprs, _) = prepare_projection(exprs, &schema, opt_flags)?;
     let mut output_names = PlHashSet::with_capacity(exprs.len());
 
     let mut arena = Arena::with_capacity(8);
@@ -1008,10 +1035,11 @@ fn resolve_group_by(
     _options: &GroupbyOptions,
     lp_arena: &Arena<IR>,
     expr_arena: &mut Arena<AExpr>,
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<(Vec<ExprIR>, Vec<ExprIR>, SchemaRef)> {
     let current_schema = lp_arena.get(input).schema(lp_arena);
     let current_schema = current_schema.as_ref();
-    let mut keys = rewrite_projections(keys, current_schema, &[])?;
+    let mut keys = rewrite_projections(keys, current_schema, &[], opt_flags)?;
 
     // Initialize schema from keys
     let mut schema = expressions_to_schema(&keys, current_schema, Context::Default)?;
@@ -1042,7 +1070,7 @@ fn resolve_group_by(
     }
     let keys_index_len = schema.len();
 
-    let aggs = rewrite_projections(aggs, current_schema, &keys)?;
+    let aggs = rewrite_projections(aggs, current_schema, &keys, opt_flags)?;
     if pop_keys {
         let _ = keys.pop();
     }

crates/polars-plan/src/plans/conversion/expr_expansion.rs

@@ -6,8 +6,9 @@ use super::*;
 pub(crate) fn prepare_projection(
     exprs: Vec<Expr>,
     schema: &Schema,
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<(Vec<Expr>, Schema)> {
-    let exprs = rewrite_projections(exprs, schema, &[])?;
+    let exprs = rewrite_projections(exprs, schema, &[], opt_flags)?;
     let schema = expressions_to_schema(&exprs, schema, Context::Default)?;
     Ok((exprs, schema))
 }
@@ -541,14 +542,18 @@ fn prepare_excluded(
 }
 
 // functions can have col(["a", "b"]) or col(String) as inputs
-fn expand_function_inputs(expr: Expr, schema: &Schema) -> PolarsResult<Expr> {
+fn expand_function_inputs(
+    expr: Expr,
+    schema: &Schema,
+    opt_flags: &mut OptFlags,
+) -> PolarsResult<Expr> {
     expr.try_map_expr(|mut e| match &mut e {
         Expr::AnonymousFunction { input, options, .. } | Expr::Function { input, options, .. }
             if options
                 .flags
                 .contains(FunctionFlags::INPUT_WILDCARD_EXPANSION) =>
         {
-            *input = rewrite_projections(core::mem::take(input), schema, &[]).unwrap();
+            *input = rewrite_projections(core::mem::take(input), schema, &[], opt_flags).unwrap();
             if input.is_empty() && !options.flags.contains(FunctionFlags::ALLOW_EMPTY_INPUTS) {
                 // Needed to visualize the error
                 *input = vec![Expr::Literal(LiteralValue::Null)];
@@ -639,12 +644,27 @@ fn find_flags(expr: &Expr) -> PolarsResult<ExpansionFlags> {
     })
 }
 
+#[cfg(feature = "dtype-struct")]
+fn toggle_cse(opt_flags: &mut OptFlags) {
+    if opt_flags.contains(OptFlags::EAGER) {
+        #[cfg(debug_assertions)]
+        {
+            use polars_core::config::verbose;
+            if verbose() {
+                eprintln!("CSE turned on because of struct expansion")
+            }
+        }
+        *opt_flags |= OptFlags::COMM_SUBEXPR_ELIM;
+    }
+}
+
 /// In case of single col(*) -> do nothing, no selection is the same as select all
 /// In other cases replace the wildcard with an expression with all columns
 pub(crate) fn rewrite_projections(
     exprs: Vec<Expr>,
     schema: &Schema,
     keys: &[Expr],
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<Vec<Expr>> {
     let mut result = Vec::with_capacity(exprs.len() + schema.len());
 
@@ -653,7 +673,7 @@ pub(crate) fn rewrite_projections(
         let result_offset = result.len();
 
         // Functions can have col(["a", "b"]) or col(String) as inputs.
-        expr = expand_function_inputs(expr, schema)?;
+        expr = expand_function_inputs(expr, schema, opt_flags)?;
 
         let mut flags = find_flags(&expr)?;
         if flags.has_selector {
@@ -662,10 +682,11 @@ pub(crate) fn rewrite_projections(
             flags.multiple_columns = true;
         }
 
-        replace_and_add_to_results(expr, flags, &mut result, schema, keys)?;
+        replace_and_add_to_results(expr, flags, &mut result, schema, keys, opt_flags)?;
 
         #[cfg(feature = "dtype-struct")]
         if flags.has_struct_field_by_index {
+            toggle_cse(opt_flags);
             for e in &mut result[result_offset..] {
                 *e = struct_index_to_field(std::mem::take(e), schema)?;
             }
@@ -680,6 +701,7 @@ fn replace_and_add_to_results(
     result: &mut Vec<Expr>,
     schema: &Schema,
     keys: &[Expr],
+    opt_flags: &mut OptFlags,
 ) -> PolarsResult<()> {
     if flags.has_nth {
         expr = replace_nth(expr, schema);
@@ -732,19 +754,21 @@ fn replace_and_add_to_results(
                             &mut intermediate,
                             schema,
                             keys,
+                            opt_flags,
                         )?;
 
                         // Then expand the fields and add to the final result vec.
                         flags.expands_fields = true;
                         flags.multiple_columns = false;
                         flags.has_wildcard = false;
                         for e in intermediate {
-                            replace_and_add_to_results(e, flags, result, schema, keys)?;
+                            replace_and_add_to_results(e, flags, result, schema, keys, opt_flags)?;
                         }
                     }
                     // has only field expansion
                     // col('a').struct.field('*')
                     else {
+                        toggle_cse(opt_flags);
                         expand_struct_fields(e, &expr, result, schema, names, &exclude)?
                     }
                 },
@@ -787,7 +811,14 @@ fn replace_selector_inner(
     match s {
         Selector::Root(expr) => {
             let local_flags = find_flags(&expr)?;
-            replace_and_add_to_results(*expr, local_flags, scratch, schema, keys)?;
+            replace_and_add_to_results(
+                *expr,
+                local_flags,
+                scratch,
+                schema,
+                keys,
+                &mut Default::default(),
+            )?;
             members.extend(scratch.drain(..))
         },
         Selector::Add(lhs, rhs) => {

crates/polars-plan/src/plans/optimizer/mod.rs

@@ -72,6 +72,13 @@ pub fn optimize(
     let opt = StackOptimizer {};
     let mut rules: Vec<Box<dyn OptimizationRule>> = Vec::with_capacity(8);
 
+    // Unset CSE
+    // This can be turned on again during ir-conversion.
+    #[allow(clippy::eq_op)]
+    #[cfg(feature = "cse")]
+    if opt_state.contains(OptFlags::EAGER) {
+        opt_state &= !(OptFlags::COMM_SUBEXPR_ELIM | OptFlags::COMM_SUBEXPR_ELIM);
+    }
     let mut lp_top = to_alp(logical_plan, expr_arena, lp_arena, &mut opt_state)?;
 
     // get toggle values
@@ -87,10 +94,10 @@ pub fn optimize(
     // This keeps eager execution more snappy.
     let eager = opt_state.contains(OptFlags::EAGER);
     #[cfg(feature = "cse")]
-    let comm_subplan_elim = opt_state.contains(OptFlags::COMM_SUBPLAN_ELIM) && !eager;
+    let comm_subplan_elim = opt_state.contains(OptFlags::COMM_SUBPLAN_ELIM);
 
     #[cfg(feature = "cse")]
-    let comm_subexpr_elim = opt_state.contains(OptFlags::COMM_SUBEXPR_ELIM) && !eager;
+    let comm_subexpr_elim = opt_state.contains(OptFlags::COMM_SUBEXPR_ELIM);
     #[cfg(not(feature = "cse"))]
     let comm_subexpr_elim = false;
 

py-polars/tests/unit/test_cse.py

@@ -783,3 +783,15 @@ def test_cse_chunks_18124() -> None:
         )
         .filter(pl.col("ts_diff") > 1)
     ).collect().shape == (4, 4)
+
+
+def test_eager_cse_during_struct_expansion_18411() -> None:
+    df = pl.DataFrame({"foo": [0, 0, 0, 1, 1]})
+    vc = pl.col("foo").value_counts()
+    classes = vc.struct[0]
+    counts = vc.struct[1]
+    # Check if output is stable
+    assert (
+        df.select(pl.col("foo").replace(classes, counts))
+        == df.select(pl.col("foo").replace(classes, counts))
+    )["foo"].all()