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ssa_range_prop: use if let guards #155779

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97 changes: 47 additions & 50 deletions compiler/rustc_mir_transform/src/ssa_range_prop.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -143,14 +143,13 @@ impl<'tcx> MutVisitor<'tcx> for RangeSet<'tcx, '_, '_> {
fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
self.super_statement(statement, location);
match &statement.kind {
StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(operand)) => {
StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(operand))
if let Some(place) = operand.place()
&& self.is_ssa(place)
{
let successor = location.successor_within_block();
let range = WrappingRange { start: 1, end: 1 };
self.insert_range(place, successor, range);
}
&& self.is_ssa(place) =>
{
let successor = location.successor_within_block();
let range = WrappingRange { start: 1, end: 1 };
self.insert_range(place, successor, range);
}
_ => {}
}
Expand All @@ -159,58 +158,56 @@ impl<'tcx> MutVisitor<'tcx> for RangeSet<'tcx, '_, '_> {
fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
self.super_terminator(terminator, location);
match &terminator.kind {
TerminatorKind::Assert { cond, expected, target, .. } => {
TerminatorKind::Assert { cond, expected, target, .. }
if let Some(place) = cond.place()
&& self.is_ssa(place)
{
let successor = Location { block: *target, statement_index: 0 };
if location.dominates(successor, &self.dominators) {
assert_ne!(location.block, successor.block);
let val = *expected as u128;
let range = WrappingRange { start: val, end: val };
self.insert_range(place, successor, range);
}
&& self.is_ssa(place) =>
{
let successor = Location { block: *target, statement_index: 0 };
if location.dominates(successor, &self.dominators) {
assert_ne!(location.block, successor.block);
let val = *expected as u128;
let range = WrappingRange { start: val, end: val };
self.insert_range(place, successor, range);
}
}
TerminatorKind::SwitchInt { discr, targets } => {
TerminatorKind::SwitchInt { discr, targets }
if let Some(place) = discr.place()
&& self.is_ssa(place)
// Reduce the potential compile-time overhead.
&& targets.all_targets().len() < 16
{
let mut distinct_targets: FxHashMap<BasicBlock, u64> = FxHashMap::default();
for (_, target) in targets.iter() {
let targets = distinct_targets.entry(target).or_default();
*targets += 1;
&& targets.all_targets().len() < 16 =>
{
let mut distinct_targets: FxHashMap<BasicBlock, u64> = FxHashMap::default();
for (_, target) in targets.iter() {
let targets = distinct_targets.entry(target).or_default();
*targets += 1;
}
for (val, target) in targets.iter() {
if distinct_targets[&target] != 1 {
// FIXME: For multiple targets, the range can be the union of their values.
continue;
}
for (val, target) in targets.iter() {
if distinct_targets[&target] != 1 {
// FIXME: For multiple targets, the range can be the union of their values.
continue;
}
let successor = Location { block: target, statement_index: 0 };
if self.unique_predecessors.contains(successor.block) {
assert_ne!(location.block, successor.block);
let range = WrappingRange { start: val, end: val };
self.insert_range(place, successor, range);
}
let successor = Location { block: target, statement_index: 0 };
if self.unique_predecessors.contains(successor.block) {
assert_ne!(location.block, successor.block);
let range = WrappingRange { start: val, end: val };
self.insert_range(place, successor, range);
}
}

// FIXME: The range for the otherwise target be extend to more types.
// For instance, `val` is within the range [4, 1) at the otherwise target of `matches!(val, 1 | 2 | 3)`.
let otherwise = Location { block: targets.otherwise(), statement_index: 0 };
if place.ty(self.local_decls, self.tcx).ty.is_bool()
&& let [val] = targets.all_values()
&& self.unique_predecessors.contains(otherwise.block)
{
assert_ne!(location.block, otherwise.block);
let range = if val.get() == 0 {
WrappingRange { start: 1, end: 1 }
} else {
WrappingRange { start: 0, end: 0 }
};
self.insert_range(place, otherwise, range);
}
// FIXME: The range for the otherwise target be extend to more types.
// For instance, `val` is within the range [4, 1) at the otherwise target of `matches!(val, 1 | 2 | 3)`.
let otherwise = Location { block: targets.otherwise(), statement_index: 0 };
if place.ty(self.local_decls, self.tcx).ty.is_bool()
&& let [val] = targets.all_values()
&& self.unique_predecessors.contains(otherwise.block)
{
assert_ne!(location.block, otherwise.block);
let range = if val.get() == 0 {
WrappingRange { start: 1, end: 1 }
} else {
WrappingRange { start: 0, end: 0 }
};
self.insert_range(place, otherwise, range);
}
}
_ => {}
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