Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Remove redundant union check in KnownPanicsLint const prop #124550

Merged
merged 1 commit into from
Apr 30, 2024
Merged

Remove redundant union check in KnownPanicsLint const prop #124550

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
47 changes: 18 additions & 29 deletions compiler/rustc_mir_transform/src/known_panics_lint.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -583,33 +583,21 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
val.into()
}

Aggregate(ref kind, ref fields) => {
// Do not const prop union fields as they can be
// made to produce values that don't match their
// underlying layout's type (see ICE #121534).
// If the last element of the `Adt` tuple
// is `Some` it indicates the ADT is a union
if let AggregateKind::Adt(_, _, _, _, Some(_)) = **kind {
return None;
};
Value::Aggregate {
fields: fields
.iter()
.map(|field| {
self.eval_operand(field).map_or(Value::Uninit, Value::Immediate)
})
.collect(),
variant: match **kind {
AggregateKind::Adt(_, variant, _, _, _) => variant,
AggregateKind::Array(_)
| AggregateKind::Tuple
| AggregateKind::RawPtr(_, _)
| AggregateKind::Closure(_, _)
| AggregateKind::Coroutine(_, _)
| AggregateKind::CoroutineClosure(_, _) => VariantIdx::ZERO,
},
}
}
Aggregate(ref kind, ref fields) => Value::Aggregate {
fields: fields
.iter()
.map(|field| self.eval_operand(field).map_or(Value::Uninit, Value::Immediate))
.collect(),
variant: match **kind {
AggregateKind::Adt(_, variant, _, _, _) => variant,
AggregateKind::Array(_)
| AggregateKind::Tuple
| AggregateKind::RawPtr(_, _)
| AggregateKind::Closure(_, _)
| AggregateKind::Coroutine(_, _)
| AggregateKind::CoroutineClosure(_, _) => VariantIdx::ZERO,
},
},

Repeat(ref op, n) => {
trace!(?op, ?n);
Expand Down Expand Up @@ -897,8 +885,9 @@ impl CanConstProp {
for (local, val) in cpv.can_const_prop.iter_enumerated_mut() {
let ty = body.local_decls[local].ty;
if ty.is_union() {
// Do not const prop unions as they can
// ICE during layout calc
// Unions are incompatible with the current implementation of
// const prop because Rust has no concept of an active
// variant of a union
*val = ConstPropMode::NoPropagation;
} else {
match tcx.layout_of(param_env.and(ty)) {
Expand Down
Loading