Rollup of 7 pull requests

compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs

@@ -1,59 +1,48 @@
-//! This module provides a pass to replacing the following statements with
-//! [`Nop`]s
+//! This module provides a pass that removes parts of MIR that are no longer relevant after
+//! analysis phase and borrowck. In particular, it removes false edges, user type annotations and
+//! replaces following statements with [`Nop`]s:
 //!
 //!   - [`AscribeUserType`]
 //!   - [`FakeRead`]
 //!   - [`Assign`] statements with a [`Shallow`] borrow
 //!
-//! The `CleanFakeReadsAndBorrows` "pass" is actually implemented as two
-//! traversals (aka visits) of the input MIR. The first traversal,
-//! `DeleteAndRecordFakeReads`, deletes the fake reads and finds the
-//! temporaries read by [`ForMatchGuard`] reads, and `DeleteFakeBorrows`
-//! deletes the initialization of those temporaries.
-//!
 //! [`AscribeUserType`]: rustc_middle::mir::StatementKind::AscribeUserType
-//! [`Shallow`]: rustc_middle::mir::BorrowKind::Shallow
-//! [`FakeRead`]: rustc_middle::mir::StatementKind::FakeRead
 //! [`Assign`]: rustc_middle::mir::StatementKind::Assign
-//! [`ForMatchGuard`]: rustc_middle::mir::FakeReadCause::ForMatchGuard
+//! [`FakeRead`]: rustc_middle::mir::StatementKind::FakeRead
 //! [`Nop`]: rustc_middle::mir::StatementKind::Nop
+//! [`Shallow`]: rustc_middle::mir::BorrowKind::Shallow
 
 use crate::MirPass;
-use rustc_middle::mir::visit::MutVisitor;
-use rustc_middle::mir::{Body, BorrowKind, Location, Rvalue};
-use rustc_middle::mir::{Statement, StatementKind};
+use rustc_middle::mir::{Body, BorrowKind, Rvalue, StatementKind, TerminatorKind};
 use rustc_middle::ty::TyCtxt;
 
-pub struct CleanupNonCodegenStatements;
+pub struct CleanupPostBorrowck;
 
-pub struct DeleteNonCodegenStatements<'tcx> {
-    tcx: TyCtxt<'tcx>,
-}
+impl<'tcx> MirPass<'tcx> for CleanupPostBorrowck {
+    fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+        for basic_block in body.basic_blocks.as_mut() {
+            for statement in basic_block.statements.iter_mut() {
+                match statement.kind {
+                    StatementKind::AscribeUserType(..)
+                    | StatementKind::Assign(box (_, Rvalue::Ref(_, BorrowKind::Shallow, _)))
+                    | StatementKind::FakeRead(..) => statement.make_nop(),
+                    _ => (),
+                }
+            }
+            let terminator = basic_block.terminator_mut();
+            match terminator.kind {
+                TerminatorKind::FalseEdge { real_target, .. }
+                | TerminatorKind::FalseUnwind { real_target, .. } => {
+                    terminator.kind = TerminatorKind::Goto { target: real_target };
+                }
+                _ => {}
+            }
+        }
 
-impl<'tcx> MirPass<'tcx> for CleanupNonCodegenStatements {
-    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let mut delete = DeleteNonCodegenStatements { tcx };
-        delete.visit_body_preserves_cfg(body);
         body.user_type_annotations.raw.clear();
 
         for decl in &mut body.local_decls {
             decl.user_ty = None;
         }
     }
 }
-
-impl<'tcx> MutVisitor<'tcx> for DeleteNonCodegenStatements<'tcx> {
-    fn tcx(&self) -> TyCtxt<'tcx> {
-        self.tcx
-    }
-
-    fn visit_statement(&mut self, statement: &mut Statement<'tcx>, location: Location) {
-        match statement.kind {
-            StatementKind::AscribeUserType(..)
-            | StatementKind::Assign(box (_, Rvalue::Ref(_, BorrowKind::Shallow, _)))
-            | StatementKind::FakeRead(..) => statement.make_nop(),
-            _ => (),
-        }
-        self.super_statement(statement, location);
-    }
-}

compiler/rustc_mir_transform/src/lib.rs

@@ -77,8 +77,6 @@ mod match_branches;
 mod multiple_return_terminators;
 mod normalize_array_len;
 mod nrvo;
-// This pass is public to allow external drivers to perform MIR cleanup
-pub mod remove_false_edges;
 mod remove_noop_landing_pads;
 mod remove_storage_markers;
 mod remove_uninit_drops;
@@ -494,10 +492,9 @@ fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>
 /// After this series of passes, no lifetime analysis based on borrowing can be done.
 fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
-        &remove_false_edges::RemoveFalseEdges,
+        &cleanup_post_borrowck::CleanupPostBorrowck,
         &simplify_branches::SimplifyConstCondition::new("initial"),
         &remove_noop_landing_pads::RemoveNoopLandingPads,
-        &cleanup_post_borrowck::CleanupNonCodegenStatements,
         &simplify::SimplifyCfg::new("early-opt"),
         &deref_separator::Derefer,
     ];

compiler/rustc_mir_transform/src/normalize_array_len.rs

@@ -16,7 +16,8 @@ pub struct NormalizeArrayLen;
 
 impl<'tcx> MirPass<'tcx> for NormalizeArrayLen {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 4
+        // See #105929
+        sess.mir_opt_level() >= 4 && sess.opts.unstable_opts.unsound_mir_opts
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

library/alloc/src/boxed.rs

@@ -2033,7 +2033,7 @@ impl<Args: Tuple, F: Fn<Args> + ?Sized, A: Allocator> Fn<Args> for Box<F, A> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized, A: Allocator> CoerceUnsized<Box<U, A>> for Box<T, A> {}
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]

library/alloc/src/rc.rs

@@ -336,7 +336,7 @@ impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Rc<T> {}
 #[stable(feature = "rc_ref_unwind_safe", since = "1.58.0")]
 impl<T: RefUnwindSafe + ?Sized> RefUnwindSafe for Rc<T> {}
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Rc<U>> for Rc<T> {}
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]
@@ -2190,7 +2190,7 @@ impl<T: ?Sized> !marker::Send for Weak<T> {}
 #[stable(feature = "rc_weak", since = "1.4.0")]
 impl<T: ?Sized> !marker::Sync for Weak<T> {}
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Weak<U>> for Weak<T> {}
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]

library/alloc/src/sync.rs

@@ -254,7 +254,7 @@ unsafe impl<T: ?Sized + Sync + Send> Sync for Arc<T> {}
 #[stable(feature = "catch_unwind", since = "1.9.0")]
 impl<T: RefUnwindSafe + ?Sized> UnwindSafe for Arc<T> {}
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Arc<U>> for Arc<T> {}
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]
@@ -306,7 +306,7 @@ unsafe impl<T: ?Sized + Sync + Send> Send for Weak<T> {}
 #[stable(feature = "arc_weak", since = "1.4.0")]
 unsafe impl<T: ?Sized + Sync + Send> Sync for Weak<T> {}
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Weak<U>> for Weak<T> {}
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Weak<U>> for Weak<T> {}

library/core/src/cell.rs

@@ -568,7 +568,7 @@ impl<T: Default> Cell<T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: CoerceUnsized<U>, U> CoerceUnsized<Cell<U>> for Cell<T> {}
 
 impl<T> Cell<[T]> {
@@ -1266,7 +1266,7 @@ impl<T> const From<T> for RefCell<T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: CoerceUnsized<U>, U> CoerceUnsized<RefCell<U>> for RefCell<T> {}
 
 struct BorrowRef<'b> {
@@ -1492,7 +1492,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'b, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Ref<'b, U>> for Ref<'b, T> {}
 
 #[stable(feature = "std_guard_impls", since = "1.20.0")]
@@ -1738,7 +1738,7 @@ impl<T: ?Sized> DerefMut for RefMut<'_, T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'b, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<RefMut<'b, U>> for RefMut<'b, T> {}
 
 #[stable(feature = "std_guard_impls", since = "1.20.0")]
@@ -2074,7 +2074,7 @@ impl<T> const From<T> for UnsafeCell<T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: CoerceUnsized<U>, U> CoerceUnsized<UnsafeCell<U>> for UnsafeCell<T> {}
 
 /// [`UnsafeCell`], but [`Sync`].
@@ -2164,7 +2164,7 @@ impl<T> const From<T> for SyncUnsafeCell<T> {
     }
 }
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 //#[unstable(feature = "sync_unsafe_cell", issue = "95439")]
 impl<T: CoerceUnsized<U>, U> CoerceUnsized<SyncUnsafeCell<U>> for SyncUnsafeCell<T> {}
 

library/core/src/marker.rs

@@ -126,7 +126,7 @@ pub trait Sized {
 /// [`Rc`]: ../../std/rc/struct.Rc.html
 /// [RFC982]: https://github.com/rust-lang/rfcs/blob/master/text/0982-dst-coercion.md
 /// [nomicon-coerce]: ../../nomicon/coercions.html
-#[unstable(feature = "unsize", issue = "27732")]
+#[unstable(feature = "unsize", issue = "18598")]
 #[lang = "unsize"]
 #[cfg_attr(not(bootstrap), rustc_deny_explicit_impl)]
 pub trait Unsize<T: ?Sized> {

library/core/src/ops/mod.rs

@@ -201,7 +201,7 @@ pub(crate) use self::try_trait::{ChangeOutputType, NeverShortCircuit};
 #[unstable(feature = "generator_trait", issue = "43122")]
 pub use self::generator::{Generator, GeneratorState};
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 pub use self::unsize::CoerceUnsized;
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]

library/core/src/ops/unsize.rs

@@ -31,41 +31,41 @@ use crate::marker::Unsize;
 /// [dst-coerce]: https://github.com/rust-lang/rfcs/blob/master/text/0982-dst-coercion.md
 /// [unsize]: crate::marker::Unsize
 /// [nomicon-coerce]: ../../nomicon/coercions.html
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 #[lang = "coerce_unsized"]
 pub trait CoerceUnsized<T: ?Sized> {
     // Empty.
 }
 
 // &mut T -> &mut U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a mut U> for &'a mut T {}
 // &mut T -> &U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b mut T {}
 // &mut T -> *mut U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for &'a mut T {}
 // &mut T -> *const U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a mut T {}
 
 // &T -> &U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, 'b: 'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<&'a U> for &'b T {}
 // &T -> *const U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for &'a T {}
 
 // *mut T -> *mut U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*mut U> for *mut T {}
 // *mut T -> *const U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *mut T {}
 
 // *const T -> *const U
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<*const U> for *const T {}
 
 /// `DispatchFromDyn` is used in the implementation of object safety checks (specifically allowing

library/core/src/ptr/non_null.rs

@@ -712,7 +712,7 @@ impl<T: ?Sized> const Clone for NonNull<T> {
 #[stable(feature = "nonnull", since = "1.25.0")]
 impl<T: ?Sized> Copy for NonNull<T> {}
 
-#[unstable(feature = "coerce_unsized", issue = "27732")]
+#[unstable(feature = "coerce_unsized", issue = "18598")]
 impl<T: ?Sized, U: ?Sized> CoerceUnsized<NonNull<U>> for NonNull<T> where T: Unsize<U> {}
 
 #[unstable(feature = "dispatch_from_dyn", issue = "none")]

src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff

@@ -12,7 +12,6 @@
       let mut _7: usize;                   // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _8: bool;                    // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _9: &[u32; 3];               // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-      let mut _10: &[u32; 3];              // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
 
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
@@ -25,16 +24,14 @@
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
           _4 = _9;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _3 = _4;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          StorageLive(_10);                // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _10 = _3;                        // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _2 = move _3 as &[u32] (Pointer(Unsize)); // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageDead(_3);                 // scope 0 at $DIR/slice_len.rs:+1:18: +1:19
           StorageLive(_6);                 // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
           _6 = const 1_usize;              // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
-          _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
-          StorageDead(_10);                // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
+-         _7 = Len((*_2));                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         _8 = Lt(_6, _7);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
++         _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         _8 = const true;                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         assert(const true, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 1_usize) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       }

src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff

@@ -12,7 +12,6 @@
       let mut _7: usize;                   // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _8: bool;                    // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _9: &[u32; 3];               // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-      let mut _10: &[u32; 3];              // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
 
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
@@ -25,16 +24,14 @@
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
           _4 = _9;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _3 = _4;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          StorageLive(_10);                // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _10 = _3;                        // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _2 = move _3 as &[u32] (Pointer(Unsize)); // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageDead(_3);                 // scope 0 at $DIR/slice_len.rs:+1:18: +1:19
           StorageLive(_6);                 // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
           _6 = const 1_usize;              // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
-          _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
-          StorageDead(_10);                // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
+-         _7 = Len((*_2));                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         _8 = Lt(_6, _7);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
++         _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         _8 = const true;                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         assert(const true, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 1_usize) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       }