bjoernager/rust
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In LexicalResolver, don't construct graph unless necessary.

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A small but easy perf win.
This commit is contained in:
Nicholas Nethercote 2023-04-19 16:15:05 +10:00
parent c609da59d9
commit 8e6c9e0694
1 changed files with 7 additions and 4 deletions
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11
compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
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@ -131,10 +131,9 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
self.dump_constraints();
}
let graph = self.construct_graph();
self.expansion(&mut var_data);
self.collect_errors(&mut var_data, errors);
self.collect_var_errors(&var_data, &graph, errors);
self.collect_var_errors(&var_data, errors);
var_data
}
@ -622,7 +621,6 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
fn collect_var_errors(
&self,
var_data: &LexicalRegionResolutions<'tcx>,
graph: &RegionGraph<'tcx>,
errors: &mut Vec<RegionResolutionError<'tcx>>,
) {
debug!("collect_var_errors, var_data = {:#?}", var_data.values);
@ -640,6 +638,10 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
// overlapping locations.
let mut dup_vec = IndexVec::from_elem_n(None, self.num_vars());
// Only construct the graph when necessary, because it's moderately
// expensive.
let mut graph = None;
for (node_vid, value) in var_data.values.iter_enumerated() {
match *value {
VarValue::Empty(_) | VarValue::Value(_) => { /* Inference successful */ }
@ -672,7 +674,8 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
// influence the constraints on this value for
// richer diagnostics in `static_impl_trait`.
self.collect_error_for_expanding_node(graph, &mut dup_vec, node_vid, errors);
let g = graph.get_or_insert_with(|| self.construct_graph());
self.collect_error_for_expanding_node(g, &mut dup_vec, node_vid, errors);
}
}
}