From 84af55679131e5074b7236fbdd98b12e9012b94e Mon Sep 17 00:00:00 2001 From: dianqk Date: Mon, 24 Mar 2025 16:55:24 +0800 Subject: [PATCH] `next_opaque` is no longer an `Option` --- compiler/rustc_mir_transform/src/gvn.rs | 69 ++++++++++++------------- 1 file changed, 32 insertions(+), 37 deletions(-) diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index 2abb4e8b8ce1..42d736cf5f49 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -130,7 +130,7 @@ impl<'tcx> crate::MirPass<'tcx> for GVN { let mut state = VnState::new(tcx, body, typing_env, &ssa, dominators, &body.local_decls); for local in body.args_iter().filter(|&local| ssa.is_ssa(local)) { - let opaque = state.new_opaque().unwrap(); + let opaque = state.new_opaque(); state.assign(local, opaque); } @@ -237,8 +237,7 @@ struct VnState<'body, 'tcx> { /// Values evaluated as constants if possible. evaluated: IndexVec>>, /// Counter to generate different values. - /// This is an option to stop creating opaques during replacement. - next_opaque: Option, + next_opaque: usize, /// Cache the value of the `unsized_locals` features, to avoid fetching it repeatedly in a loop. feature_unsized_locals: bool, ssa: &'body SsaLocals, @@ -270,7 +269,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { rev_locals: IndexVec::with_capacity(num_values), values: FxIndexSet::with_capacity_and_hasher(num_values, Default::default()), evaluated: IndexVec::with_capacity(num_values), - next_opaque: Some(1), + next_opaque: 1, feature_unsized_locals: tcx.features().unsized_locals(), ssa, dominators, @@ -291,32 +290,31 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { let evaluated = self.eval_to_const(index); let _index = self.evaluated.push(evaluated); debug_assert_eq!(index, _index); - // No need to push to `rev_locals` if we finished listing assignments. - if self.next_opaque.is_some() { - let _index = self.rev_locals.push(SmallVec::new()); - debug_assert_eq!(index, _index); - } + let _index = self.rev_locals.push(SmallVec::new()); + debug_assert_eq!(index, _index); } index } + fn next_opaque(&mut self) -> usize { + let next_opaque = self.next_opaque; + self.next_opaque += 1; + next_opaque + } + /// Create a new `Value` for which we have no information at all, except that it is distinct /// from all the others. #[instrument(level = "trace", skip(self), ret)] - fn new_opaque(&mut self) -> Option { - let next_opaque = self.next_opaque.as_mut()?; - let value = Value::Opaque(*next_opaque); - *next_opaque += 1; - Some(self.insert(value)) + fn new_opaque(&mut self) -> VnIndex { + let value = Value::Opaque(self.next_opaque()); + self.insert(value) } /// Create a new `Value::Address` distinct from all the others. #[instrument(level = "trace", skip(self), ret)] - fn new_pointer(&mut self, place: Place<'tcx>, kind: AddressKind) -> Option { - let next_opaque = self.next_opaque.as_mut()?; - let value = Value::Address { place, kind, provenance: *next_opaque }; - *next_opaque += 1; - Some(self.insert(value)) + fn new_pointer(&mut self, place: Place<'tcx>, kind: AddressKind) -> VnIndex { + let value = Value::Address { place, kind, provenance: self.next_opaque() }; + self.insert(value) } fn get(&self, index: VnIndex) -> &Value<'tcx> { @@ -337,21 +335,19 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } } - fn insert_constant(&mut self, value: Const<'tcx>) -> Option { + fn insert_constant(&mut self, value: Const<'tcx>) -> VnIndex { let disambiguator = if value.is_deterministic() { // The constant is deterministic, no need to disambiguate. 0 } else { // Multiple mentions of this constant will yield different values, // so assign a different `disambiguator` to ensure they do not get the same `VnIndex`. - let next_opaque = self.next_opaque.as_mut()?; - let disambiguator = *next_opaque; - *next_opaque += 1; + let disambiguator = self.next_opaque(); // `disambiguator: 0` means deterministic. debug_assert_ne!(disambiguator, 0); disambiguator }; - Some(self.insert(Value::Constant { value, disambiguator })) + self.insert(Value::Constant { value, disambiguator }) } fn insert_bool(&mut self, flag: bool) -> VnIndex { @@ -812,7 +808,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { location: Location, ) -> Option { match *operand { - Operand::Constant(ref constant) => self.insert_constant(constant.const_), + Operand::Constant(ref constant) => Some(self.insert_constant(constant.const_)), Operand::Copy(ref mut place) | Operand::Move(ref mut place) => { let value = self.simplify_place_value(place, location)?; if let Some(const_) = self.try_as_constant(value) { @@ -848,11 +844,11 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { Rvalue::Aggregate(..) => return self.simplify_aggregate(rvalue, location), Rvalue::Ref(_, borrow_kind, ref mut place) => { self.simplify_place_projection(place, location); - return self.new_pointer(*place, AddressKind::Ref(borrow_kind)); + return Some(self.new_pointer(*place, AddressKind::Ref(borrow_kind))); } Rvalue::RawPtr(mutbl, ref mut place) => { self.simplify_place_projection(place, location); - return self.new_pointer(*place, AddressKind::Address(mutbl)); + return Some(self.new_pointer(*place, AddressKind::Address(mutbl))); } Rvalue::WrapUnsafeBinder(ref mut op, ty) => { let value = self.simplify_operand(op, location)?; @@ -1016,7 +1012,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { if is_zst { let ty = rvalue.ty(self.local_decls, tcx); - return self.insert_constant(Const::zero_sized(ty)); + return Some(self.insert_constant(Const::zero_sized(ty))); } } @@ -1045,11 +1041,10 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } }; - let fields: Option> = field_ops + let mut fields: Vec<_> = field_ops .iter_mut() - .map(|op| self.simplify_operand(op, location).or_else(|| self.new_opaque())) + .map(|op| self.simplify_operand(op, location).unwrap_or_else(|| self.new_opaque())) .collect(); - let mut fields = fields?; if let AggregateTy::RawPtr { data_pointer_ty, output_pointer_ty } = &mut ty { let mut was_updated = false; @@ -1177,7 +1172,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { ) if let ty::Slice(..) = to.builtin_deref(true).unwrap().kind() && let ty::Array(_, len) = from.builtin_deref(true).unwrap().kind() => { - return self.insert_constant(Const::Ty(self.tcx.types.usize, *len)); + return Some(self.insert_constant(Const::Ty(self.tcx.types.usize, *len))); } _ => Value::UnaryOp(op, arg_index), }; @@ -1373,7 +1368,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { if let CastKind::PointerCoercion(ReifyFnPointer | ClosureFnPointer(_), _) = kind { // Each reification of a generic fn may get a different pointer. // Do not try to merge them. - return self.new_opaque(); + return Some(self.new_opaque()); } let mut was_ever_updated = false; @@ -1489,7 +1484,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { // Trivial case: we are fetching a statically known length. let place_ty = place.ty(self.local_decls, self.tcx).ty; if let ty::Array(_, len) = place_ty.kind() { - return self.insert_constant(Const::Ty(self.tcx.types.usize, *len)); + return Some(self.insert_constant(Const::Ty(self.tcx.types.usize, *len))); } let mut inner = self.simplify_place_value(place, location)?; @@ -1511,7 +1506,7 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { && let Some(to) = to.builtin_deref(true) && let ty::Slice(..) = to.kind() { - return self.insert_constant(Const::Ty(self.tcx.types.usize, *len)); + return Some(self.insert_constant(Const::Ty(self.tcx.types.usize, *len))); } // Fallback: a symbolic `Len`. @@ -1740,7 +1735,7 @@ impl<'tcx> MutVisitor<'tcx> for VnState<'_, 'tcx> { // `local` as reusable if we have an exact type match. && self.local_decls[local].ty == rvalue.ty(self.local_decls, self.tcx) { - let value = value.or_else(|| self.new_opaque()).unwrap(); + let value = value.unwrap_or_else(|| self.new_opaque()); self.assign(local, value); Some(value) } else { @@ -1767,7 +1762,7 @@ impl<'tcx> MutVisitor<'tcx> for VnState<'_, 'tcx> { && let Some(local) = destination.as_local() && self.ssa.is_ssa(local) { - let opaque = self.new_opaque().unwrap(); + let opaque = self.new_opaque(); self.assign(local, opaque); } self.super_terminator(terminator, location);