bjoernager/rust
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Rm allocation in uninhabited_enum_branching

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Also convert `uninhabited_enum_branching` `Cow<[u128]>::to_mut`
This commit is contained in:
kadmin 2020-08-13 22:54:09 +00:00
parent 70ad31847d
commit fd63bf7262
3 changed files with 32 additions and 52 deletions
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43
src/librustc_mir/transform/simplify_try.rs
View file

@ -246,12 +246,14 @@ fn get_arm_identity_info<'a, 'tcx>(
tmp_assigned_vars.insert(*r);
}
let mut dbg_info_to_adjust = Vec::new();
for (i, var_info) in debug_info.iter().enumerate() {
if tmp_assigned_vars.contains(var_info.place.local) {
dbg_info_to_adjust.push(i);
}
}
let dbg_info_to_adjust: Vec<_> =
debug_info
.iter()
.enumerate()
.filter_map(|(i, var_info)| {
if tmp_assigned_vars.contains(var_info.place.local) { Some(i) } else { None }
})
.collect();
Some(ArmIdentityInfo {
local_temp_0: local_tmp_s0,
@ -461,14 +463,14 @@ fn match_get_variant_field<'tcx>(
stmt: &Statement<'tcx>,
) -> Option<(Local, Local, VarField<'tcx>, &'tcx List<PlaceElem<'tcx>>)> {
match &stmt.kind {
StatementKind::Assign(box (place_into, rvalue_from)) => match rvalue_from {
Rvalue::Use(Operand::Copy(pf) | Operand::Move(pf)) => {
let local_into = place_into.as_local()?;
let (local_from, vf) = match_variant_field_place(*pf)?;
Some((local_into, local_from, vf, pf.projection))
}
_ => None,
},
StatementKind::Assign(box (
place_into,
Rvalue::Use(Operand::Copy(pf) | Operand::Move(pf)),
)) => {
let local_into = place_into.as_local()?;
let (local_from, vf) = match_variant_field_place(*pf)?;
Some((local_into, local_from, vf, pf.projection))
}
_ => None,
}
}
@ -479,14 +481,11 @@ fn match_get_variant_field<'tcx>(
/// ```
fn match_set_variant_field<'tcx>(stmt: &Statement<'tcx>) -> Option<(Local, Local, VarField<'tcx>)> {
match &stmt.kind {
StatementKind::Assign(box (place_from, rvalue_into)) => match rvalue_into {
Rvalue::Use(Operand::Move(place_into)) => {
let local_into = place_into.as_local()?;
let (local_from, vf) = match_variant_field_place(*place_from)?;
Some((local_into, local_from, vf))
}
_ => None,
},
StatementKind::Assign(box (place_from, Rvalue::Use(Operand::Move(place_into)))) => {
let local_into = place_into.as_local()?;
let (local_from, vf) = match_variant_field_place(*place_from)?;
Some((local_into, local_from, vf))
}
_ => None,
}
}

30
src/librustc_mir/transform/uninhabited_enum_branching.rs
View file

@ -99,26 +99,18 @@ impl<'tcx> MirPass<'tcx> for UninhabitedEnumBranching {
if let TerminatorKind::SwitchInt { values, targets, .. } =
&mut body.basic_blocks_mut()[bb].terminator_mut().kind
{
let vals = &*values;
let zipped = vals.iter().zip(targets.iter());
// take otherwise out early
let otherwise = targets.pop().unwrap();
assert_eq!(targets.len(), values.len());
let mut i = 0;
targets.retain(|_| {
let keep = allowed_variants.contains(&values[i]);
i += 1;
keep
});
targets.push(otherwise);
let mut matched_values = Vec::with_capacity(allowed_variants.len());
let mut matched_targets = Vec::with_capacity(allowed_variants.len() + 1);
for (val, target) in zipped {
if allowed_variants.contains(val) {
matched_values.push(*val);
matched_targets.push(*target);
} else {
trace!("eliminating {:?} -> {:?}", val, target);
}
}
// handle the "otherwise" branch
matched_targets.push(targets.pop().unwrap());
*values = matched_values.into();
*targets = matched_targets;
values.to_mut().retain(|var| allowed_variants.contains(var));
} else {
unreachable!()
}

11
src/librustc_mir/transform/unreachable_prop.rs
View file

@ -68,17 +68,6 @@ where
F: Fn(BasicBlock) -> bool,
{
let terminator = match *terminator_kind {
TerminatorKind::FalseEdge { real_target, imaginary_target }
if predicate(real_target) && predicate(imaginary_target) =>
{
TerminatorKind::Unreachable
}
TerminatorKind::FalseUnwind { real_target, unwind }
if predicate(real_target) && unwind.map_or(true, &predicate) =>
{
TerminatorKind::Unreachable
}
TerminatorKind::Goto { target } if predicate(target) => TerminatorKind::Unreachable,
TerminatorKind::SwitchInt { ref discr, switch_ty, ref values, ref targets } => {
let original_targets_len = targets.len();