diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/syntax.rs')
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 23 |
1 files changed, 5 insertions, 18 deletions
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index 6039a03aa29..e6c8512564e 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -327,9 +327,11 @@ pub enum StatementKind<'tcx> { /// interesting for optimizations? Do we want to allow such optimizations? /// /// **Needs clarification**: We currently require that the LHS place not overlap with any place - /// read as part of computation of the RHS for some rvalues (generally those not producing - /// primitives). This requirement is under discussion in [#68364]. As a part of this discussion, - /// it is also unclear in what order the components are evaluated. + /// read as part of computation of the RHS for some rvalues. This requirement is under + /// discussion in [#68364]. Specifically, overlap is permitted only for assignments of a type + /// with `BackendRepr::Scalar | BackendRepr::ScalarPair` where all the scalar fields are + /// [`Scalar::Initialized`][rustc_abi::Scalar::Initialized]. As a part of this discussion, it is + /// also unclear in what order the components are evaluated. /// /// [#68364]: https://github.com/rust-lang/rust/issues/68364 /// @@ -1371,12 +1373,7 @@ pub enum Rvalue<'tcx> { /// Creates an array where each element is the value of the operand. /// - /// This is the cause of a bug in the case where the repetition count is zero because the value - /// is not dropped, see [#74836]. - /// /// Corresponds to source code like `[x; 32]`. - /// - /// [#74836]: https://github.com/rust-lang/rust/issues/74836 Repeat(Operand<'tcx>, ty::Const<'tcx>), /// Creates a reference of the indicated kind to the place. @@ -1410,16 +1407,6 @@ pub enum Rvalue<'tcx> { /// model. RawPtr(RawPtrKind, Place<'tcx>), - /// Yields the length of the place, as a `usize`. - /// - /// If the type of the place is an array, this is the array length. For slices (`[T]`, not - /// `&[T]`) this accesses the place's metadata to determine the length. This rvalue is - /// ill-formed for places of other types. - /// - /// This cannot be a `UnOp(PtrMetadata, _)` because that expects a value, and we only - /// have a place, and `UnOp(PtrMetadata, RawPtr(place))` is not a thing. - Len(Place<'tcx>), - /// Performs essentially all of the casts that can be performed via `as`. /// /// This allows for casts from/to a variety of types. |