bjoernager/rust
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Move the loop out of the function

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This commit is contained in:
Nadrieril 2024-02-16 04:26:50 +01:00
parent e561dbb0b6
commit 998d0e9793
1 changed files with 50 additions and 51 deletions
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101
compiler/rustc_mir_build/src/build/matches/mod.rs
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@ -1207,7 +1207,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
&mut self,
span: Span,
scrutinee_span: Span,
start_block: BasicBlock,
mut start_block: BasicBlock,
otherwise_block: BasicBlock,
candidates: &mut [&mut Candidate<'_, 'tcx>],
fake_borrows: &mut Option<FxIndexSet<Place<'tcx>>>,
@ -1219,14 +1219,16 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
debug!("match_candidates: {:?} candidates fully matched", fully_matched);
let (matched_candidates, unmatched_candidates) = candidates.split_at_mut(fully_matched);
let block = self.select_matched_candidates(matched_candidates, start_block, fake_borrows);
for candidate in matched_candidates.iter_mut() {
start_block = self.select_matched_candidate(candidate, start_block, fake_borrows);
}
// If there are no candidates that still need testing, we're
// done. Since all matches are exhaustive, execution should
// never reach this point.
if unmatched_candidates.is_empty() {
let source_info = self.source_info(span);
self.cfg.goto(block, source_info, otherwise_block);
self.cfg.goto(start_block, source_info, otherwise_block);
return;
}
@ -1235,7 +1237,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
span,
scrutinee_span,
unmatched_candidates,
block,
start_block,
otherwise_block,
fake_borrows,
);
@ -1260,67 +1262,64 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
/// * the [otherwise block] of the third pattern to a block with an
/// [`Unreachable` terminator](TerminatorKind::Unreachable).
///
/// In addition, we add fake edges from the otherwise blocks to the
/// In addition, we later add fake edges from the otherwise blocks to the
/// pre-binding block of the next candidate in the original set of
/// candidates.
///
/// [pre-binding block]: Candidate::pre_binding_block
/// [otherwise block]: Candidate::otherwise_block
fn select_matched_candidates(
fn select_matched_candidate(
&mut self,
matched_candidates: &mut [&mut Candidate<'_, 'tcx>],
candidate: &mut Candidate<'_, 'tcx>,
start_block: BasicBlock,
fake_borrows: &mut Option<FxIndexSet<Place<'tcx>>>,
) -> BasicBlock {
let mut next_prebinding = start_block;
for candidate in matched_candidates.iter_mut() {
assert!(candidate.otherwise_block.is_none());
assert!(candidate.pre_binding_block.is_none());
debug_assert!(
candidate.subcandidates.is_empty(),
"subcandidates should be empty in select_matched_candidates",
);
assert!(candidate.otherwise_block.is_none());
assert!(candidate.pre_binding_block.is_none());
debug_assert!(
candidate.subcandidates.is_empty(),
"subcandidates should be empty in select_matched_candidates",
);
if let Some(fake_borrows) = fake_borrows {
// Insert a borrows of prefixes of places that are bound and are
// behind a dereference projection.
//
// These borrows are taken to avoid situations like the following:
//
// match x[10] {
// _ if { x = &[0]; false } => (),
// y => (), // Out of bounds array access!
// }
//
// match *x {
// // y is bound by reference in the guard and then by copy in the
// // arm, so y is 2 in the arm!
// y if { y == 1 && (x = &2) == () } => y,
// _ => 3,
// }
for Binding { source, .. } in &candidate.bindings {
if let Some(i) =
source.projection.iter().rposition(|elem| elem == ProjectionElem::Deref)
{
let proj_base = &source.projection[..i];
if let Some(fake_borrows) = fake_borrows {
// Insert a borrows of prefixes of places that are bound and are
// behind a dereference projection.
//
// These borrows are taken to avoid situations like the following:
//
// match x[10] {
// _ if { x = &[0]; false } => (),
// y => (), // Out of bounds array access!
// }
//
// match *x {
// // y is bound by reference in the guard and then by copy in the
// // arm, so y is 2 in the arm!
// y if { y == 1 && (x = &2) == () } => y,
// _ => 3,
// }
for Binding { source, .. } in &candidate.bindings {
if let Some(i) =
source.projection.iter().rposition(|elem| elem == ProjectionElem::Deref)
{
let proj_base = &source.projection[..i];
fake_borrows.insert(Place {
local: source.local,
projection: self.tcx.mk_place_elems(proj_base),
});
}
fake_borrows.insert(Place {
local: source.local,
projection: self.tcx.mk_place_elems(proj_base),
});
}
}
candidate.pre_binding_block = Some(next_prebinding);
next_prebinding = self.cfg.start_new_block();
if candidate.has_guard {
// Create the otherwise block for this candidate, which is the
// pre-binding block for the next candidate.
candidate.otherwise_block = Some(next_prebinding);
}
}
next_prebinding
candidate.pre_binding_block = Some(start_block);
let otherwise_block = self.cfg.start_new_block();
if candidate.has_guard {
// Create the otherwise block for this candidate, which is the
// pre-binding block for the next candidate.
candidate.otherwise_block = Some(otherwise_block);
}
otherwise_block
}
/// Tests a candidate where there are only or-patterns left to test, or