diff options
| -rw-r--r-- | compiler/rustc_mir_build/src/build/matches/mod.rs | 18 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/build/matches/simplify.rs | 39 |
2 files changed, 26 insertions, 31 deletions
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs index 74be541d962..b35a0c3c671 100644 --- a/compiler/rustc_mir_build/src/build/matches/mod.rs +++ b/compiler/rustc_mir_build/src/build/matches/mod.rs @@ -1168,7 +1168,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // be a switch or pattern comparison. let mut split_or_candidate = false; for candidate in &mut *candidates { - split_or_candidate |= self.simplify_candidate(candidate); + self.simplify_candidate(candidate); + if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place, .. }] = + &*candidate.match_pairs + { + // Split a candidate in which the only match-pair is an or-pattern into multiple + // candidates. This is so that + // + // match x { + // 0 | 1 => { ... }, + // 2 | 3 => { ... }, + // } + // + // only generates a single switch. + candidate.subcandidates = self.create_or_subcandidates(candidate, place, pats); + candidate.match_pairs.pop(); + split_or_candidate = true; + } } ensure_sufficient_stack(|| { diff --git a/compiler/rustc_mir_build/src/build/matches/simplify.rs b/compiler/rustc_mir_build/src/build/matches/simplify.rs index dba8e8b6499..a74b664441a 100644 --- a/compiler/rustc_mir_build/src/build/matches/simplify.rs +++ b/compiler/rustc_mir_build/src/build/matches/simplify.rs @@ -23,23 +23,8 @@ use std::mem; impl<'a, 'tcx> Builder<'a, 'tcx> { /// Simplify a candidate so that all match pairs require a test. - /// - /// This method will also split a candidate, in which the only - /// match-pair is an or-pattern, into multiple candidates. - /// This is so that - /// - /// match x { - /// 0 | 1 => { ... }, - /// 2 | 3 => { ... }, - /// } - /// - /// only generates a single switch. If this happens this method returns - /// `true`. #[instrument(skip(self, candidate), level = "debug")] - pub(super) fn simplify_candidate<'pat>( - &mut self, - candidate: &mut Candidate<'pat, 'tcx>, - ) -> bool { + pub(super) fn simplify_candidate<'pat>(&mut self, candidate: &mut Candidate<'pat, 'tcx>) { debug!("{candidate:#?}"); // In order to please the borrow checker, in a pattern like `x @ pat` we must lower the // bindings in `pat` before `x`. E.g. (#69971): @@ -97,30 +82,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { // Store computed bindings back in `candidate`. mem::swap(&mut candidate.bindings, &mut accumulated_bindings); - let did_expand_or = - if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place }] = - &*candidate.match_pairs - { - candidate.subcandidates = self.create_or_subcandidates(candidate, place, pats); - candidate.match_pairs.clear(); - true - } else { - false - }; - // Move or-patterns to the end, because they can result in us // creating additional candidates, so we want to test them as // late as possible. candidate.match_pairs.sort_by_key(|pair| matches!(pair.pattern.kind, PatKind::Or { .. })); debug!(simplified = ?candidate, "simplify_candidate"); - - did_expand_or } /// Given `candidate` that has a single or-pattern for its match-pairs, /// creates a fresh candidate for each of its input subpatterns passed via /// `pats`. - fn create_or_subcandidates<'pat>( + pub(super) fn create_or_subcandidates<'pat>( &mut self, candidate: &Candidate<'pat, 'tcx>, place: &PlaceBuilder<'tcx>, @@ -130,6 +102,13 @@ impl<'a, 'tcx> Builder<'a, 'tcx> { .map(|box pat| { let mut candidate = Candidate::new(place.clone(), pat, candidate.has_guard, self); self.simplify_candidate(&mut candidate); + + if let [MatchPair { pattern: Pat { kind: PatKind::Or { pats }, .. }, place, .. }] = + &*candidate.match_pairs + { + candidate.subcandidates = self.create_or_subcandidates(&candidate, place, pats); + candidate.match_pairs.pop(); + } candidate }) .collect() |