Auto merge of #97158 - JakobDegen:dse, r=tmiasko,cjgillot

Split dead store elimination off dest prop

This splits off a part of #96451 . I've added this in as its own pass for now, so that it actually runs, can be tested, etc. In the dest prop PR, I'll stop invoking this as its own pass, so that it doesn't get invoked twice.

r? `@tmiasko`

compiler/rustc_middle/src/mir/tcx.rs

@@ -4,6 +4,7 @@
  */
 
 use crate::mir::*;
+use crate::ty::cast::CastTy;
 use crate::ty::subst::Subst;
 use crate::ty::{self, Ty, TyCtxt};
 use rustc_hir as hir;
@@ -223,6 +224,22 @@ pub fn initialization_state(&self) -> RvalueInitializationState {
             _ => RvalueInitializationState::Deep,
         }
     }
+
+    pub fn is_pointer_int_cast<D>(&self, local_decls: &D, tcx: TyCtxt<'tcx>) -> bool
+    where
+        D: HasLocalDecls<'tcx>,
+    {
+        if let Rvalue::Cast(CastKind::Misc, src_op, dest_ty) = self {
+            if let Some(CastTy::Int(_)) = CastTy::from_ty(*dest_ty) {
+                let src_ty = src_op.ty(local_decls, tcx);
+                if let Some(CastTy::FnPtr | CastTy::Ptr(_)) = CastTy::from_ty(src_ty) {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
 }
 
 impl<'tcx> Operand<'tcx> {

compiler/rustc_mir_dataflow/src/impls/liveness.rs

-use rustc_index::bit_set::BitSet;
+use rustc_index::bit_set::{BitSet, ChunkedBitSet};
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
-use rustc_middle::mir::{self, Local, Location};
+use rustc_middle::mir::{self, Local, LocalDecls, Location, Place, StatementKind};
+use rustc_middle::ty::TyCtxt;
 
-use crate::{AnalysisDomain, Backward, CallReturnPlaces, GenKill, GenKillAnalysis};
+use crate::{Analysis, AnalysisDomain, Backward, CallReturnPlaces, GenKill, GenKillAnalysis};
 
 /// A [live-variable dataflow analysis][liveness].
 ///
@@ -98,19 +99,16 @@ impl<'tcx, T> Visitor<'tcx> for TransferFunction<'_, T>
     T: GenKill<Local>,
 {
     fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, location: Location) {
-        let mir::Place { projection, local } = *place;
+        let local = place.local;
 
         // We purposefully do not call `super_place` here to avoid calling `visit_local` for this
         // place with one of the `Projection` variants of `PlaceContext`.
         self.visit_projection(place.as_ref(), context, location);
 
-        match DefUse::for_place(context) {
-            // Treat derefs as a use of the base local. `*p = 4` is not a def of `p` but a use.
-            Some(_) if place.is_indirect() => self.0.gen(local),
-
-            Some(DefUse::Def) if projection.is_empty() => self.0.kill(local),
+        match DefUse::for_place(*place, context) {
+            Some(DefUse::Def) => self.0.kill(local),
             Some(DefUse::Use) => self.0.gen(local),
-            _ => {}
+            None => {}
         }
     }
 
@@ -118,10 +116,10 @@ fn visit_local(&mut self, &local: &Local, context: PlaceContext, _: Location) {
         // Because we do not call `super_place` above, `visit_local` is only called for locals that
         // do not appear as part of  a `Place` in the MIR. This handles cases like the implicit use
         // of the return place in a `Return` terminator or the index in an `Index` projection.
-        match DefUse::for_place(context) {
+        match DefUse::for_place(local.into(), context) {
             Some(DefUse::Def) => self.0.kill(local),
             Some(DefUse::Use) => self.0.gen(local),
-            _ => {}
+            None => {}
         }
     }
 }
@@ -133,27 +131,37 @@ enum DefUse {
 }
 
 impl DefUse {
-    fn for_place(context: PlaceContext) -> Option<DefUse> {
+    fn for_place<'tcx>(place: Place<'tcx>, context: PlaceContext) -> Option<DefUse> {
         match context {
             PlaceContext::NonUse(_) => None,
 
             PlaceContext::MutatingUse(MutatingUseContext::Store | MutatingUseContext::Deinit) => {
+                if place.is_indirect() {
+                    // Treat derefs as a use of the base local. `*p = 4` is not a def of `p` but a
+                    // use.
+                    Some(DefUse::Use)
+                } else if place.projection.is_empty() {
                     Some(DefUse::Def)
+                } else {
+                    None
+                }
             }
 
             // Setting the discriminant is not a use because it does no reading, but it is also not
             // a def because it does not overwrite the whole place
-            PlaceContext::MutatingUse(MutatingUseContext::SetDiscriminant) => None,
+            PlaceContext::MutatingUse(MutatingUseContext::SetDiscriminant) => {
+                place.is_indirect().then_some(DefUse::Use)
+            }
 
-            // `MutatingUseContext::Call` and `MutatingUseContext::Yield` indicate that this is the
-            // destination place for a `Call` return or `Yield` resume respectively. Since this is
-            // only a `Def` when the function returns successfully, we handle this case separately
-            // in `call_return_effect` above.
+            // For the associated terminators, this is only a `Def` when the terminator returns
+            // "successfully." As such, we handle this case separately in `call_return_effect`
+            // above. However, if the place looks like `*_5`, this is still unconditionally a use of
+            // `_5`.
             PlaceContext::MutatingUse(
                 MutatingUseContext::Call
-                | MutatingUseContext::AsmOutput
-                | MutatingUseContext::Yield,
-            ) => None,
+                | MutatingUseContext::Yield
+                | MutatingUseContext::AsmOutput,
+            ) => place.is_indirect().then_some(DefUse::Use),
 
             // All other contexts are uses...
             PlaceContext::MutatingUse(
@@ -179,3 +187,133 @@ fn for_place(context: PlaceContext) -> Option<DefUse> {
         }
     }
 }
+
+/// Like `MaybeLiveLocals`, but does not mark locals as live if they are used in a dead assignment.
+///
+/// This is basically written for dead store elimination and nothing else.
+///
+/// All of the caveats of `MaybeLiveLocals` apply.
+pub struct MaybeTransitiveLiveLocals<'a, 'tcx> {
+    always_live: &'a BitSet<Local>,
+    local_decls: &'a LocalDecls<'tcx>,
+    tcx: TyCtxt<'tcx>,
+}
+
+impl<'a, 'tcx> MaybeTransitiveLiveLocals<'a, 'tcx> {
+    /// The `always_alive` set is the set of locals to which all stores should unconditionally be
+    /// considered live.
+    ///
+    /// This should include at least all locals that are ever borrowed.
+    pub fn new(
+        always_live: &'a BitSet<Local>,
+        local_decls: &'a LocalDecls<'tcx>,
+        tcx: TyCtxt<'tcx>,
+    ) -> Self {
+        MaybeTransitiveLiveLocals { always_live, local_decls, tcx }
+    }
+}
+
+impl<'a, 'tcx> AnalysisDomain<'tcx> for MaybeTransitiveLiveLocals<'a, 'tcx> {
+    type Domain = ChunkedBitSet<Local>;
+    type Direction = Backward;
+
+    const NAME: &'static str = "transitive liveness";
+
+    fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
+        // bottom = not live
+        ChunkedBitSet::new_empty(body.local_decls.len())
+    }
+
+    fn initialize_start_block(&self, _: &mir::Body<'tcx>, _: &mut Self::Domain) {
+        // No variables are live until we observe a use
+    }
+}
+
+struct TransferWrapper<'a>(&'a mut ChunkedBitSet<Local>);
+
+impl<'a> GenKill<Local> for TransferWrapper<'a> {
+    fn gen(&mut self, l: Local) {
+        self.0.insert(l);
+    }
+
+    fn kill(&mut self, l: Local) {
+        self.0.remove(l);
+    }
+}
+
+impl<'a, 'tcx> Analysis<'tcx> for MaybeTransitiveLiveLocals<'a, 'tcx> {
+    fn apply_statement_effect(
+        &self,
+        trans: &mut Self::Domain,
+        statement: &mir::Statement<'tcx>,
+        location: Location,
+    ) {
+        // Compute the place that we are storing to, if any
+        let destination = match &statement.kind {
+            StatementKind::Assign(assign) => {
+                if assign.1.is_pointer_int_cast(self.local_decls, self.tcx) {
+                    // Pointer to int casts may be side-effects due to exposing the provenance.
+                    // While the model is undecided, we should be conservative. See
+                    // <https://www.ralfj.de/blog/2022/04/11/provenance-exposed.html>
+                    None
+                } else {
+                    Some(assign.0)
+                }
+            }
+            StatementKind::SetDiscriminant { place, .. } | StatementKind::Deinit(place) => {
+                Some(**place)
+            }
+            StatementKind::FakeRead(_)
+            | StatementKind::StorageLive(_)
+            | StatementKind::StorageDead(_)
+            | StatementKind::Retag(..)
+            | StatementKind::AscribeUserType(..)
+            | StatementKind::Coverage(..)
+            | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Nop => None,
+        };
+        if let Some(destination) = destination {
+            if !destination.is_indirect()
+                && !trans.contains(destination.local)
+                && !self.always_live.contains(destination.local)
+            {
+                // This store is dead
+                return;
+            }
+        }
+        TransferFunction(&mut TransferWrapper(trans)).visit_statement(statement, location);
+    }
+
+    fn apply_terminator_effect(
+        &self,
+        trans: &mut Self::Domain,
+        terminator: &mir::Terminator<'tcx>,
+        location: Location,
+    ) {
+        TransferFunction(&mut TransferWrapper(trans)).visit_terminator(terminator, location);
+    }
+
+    fn apply_call_return_effect(
+        &self,
+        trans: &mut Self::Domain,
+        _block: mir::BasicBlock,
+        return_places: CallReturnPlaces<'_, 'tcx>,
+    ) {
+        return_places.for_each(|place| {
+            if let Some(local) = place.as_local() {
+                trans.remove(local);
+            }
+        });
+    }
+
+    fn apply_yield_resume_effect(
+        &self,
+        trans: &mut Self::Domain,
+        _resume_block: mir::BasicBlock,
+        resume_place: mir::Place<'tcx>,
+    ) {
+        if let Some(local) = resume_place.as_local() {
+            trans.remove(local);
+        }
+    }
+}

compiler/rustc_mir_dataflow/src/impls/mod.rs

@@ -26,6 +26,7 @@
 pub use self::borrowed_locals::MaybeBorrowedLocals;
 pub use self::init_locals::MaybeInitializedLocals;
 pub use self::liveness::MaybeLiveLocals;
+pub use self::liveness::MaybeTransitiveLiveLocals;
 pub use self::storage_liveness::{MaybeRequiresStorage, MaybeStorageLive};
 
 /// `MaybeInitializedPlaces` tracks all places that might be

compiler/rustc_mir_transform/src/dead_store_elimination.rs

+//! This module implements a dead store elimination (DSE) routine.
+//!
+//! This transformation was written specifically for the needs of dest prop. Although it is
+//! perfectly sound to use it in any context that might need it, its behavior should not be changed
+//! without analyzing the interaction this will have with dest prop. Specifically, in addition to
+//! the soundness of this pass in general, dest prop needs it to satisfy two additional conditions:
+//!
+//!  1. It's idempotent, meaning that running this pass a second time immediately after running it a
+//!     first time will not cause any further changes.
+//!  2. This idempotence persists across dest prop's main transform, in other words inserting any
+//!     number of iterations of dest prop between the first and second application of this transform
+//!     will still not cause any further changes.
+//!
+
+use rustc_index::bit_set::BitSet;
+use rustc_middle::{
+    mir::{visit::Visitor, *},
+    ty::TyCtxt,
+};
+use rustc_mir_dataflow::{impls::MaybeTransitiveLiveLocals, Analysis};
+
+/// Performs the optimization on the body
+///
+/// The `borrowed` set must be a `BitSet` of all the locals that are ever borrowed in this body. It
+/// can be generated via the [`get_borrowed_locals`] function.
+pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitSet<Local>) {
+    let mut live = MaybeTransitiveLiveLocals::new(borrowed, &body.local_decls, tcx)
+        .into_engine(tcx, body)
+        .iterate_to_fixpoint()
+        .into_results_cursor(body);
+
+    let mut patch = Vec::new();
+    for (bb, bb_data) in traversal::preorder(body) {
+        for (statement_index, statement) in bb_data.statements.iter().enumerate().rev() {
+            let loc = Location { block: bb, statement_index };
+            if let StatementKind::Assign(assign) = &statement.kind {
+                if assign.1.is_pointer_int_cast(&body.local_decls, tcx) {
+                    continue;
+                }
+            }
+            match &statement.kind {
+                StatementKind::Assign(box (place, _))
+                | StatementKind::SetDiscriminant { place: box place, .. }
+                | StatementKind::Deinit(box place) => {
+                    if !place.is_indirect() && !borrowed.contains(place.local) {
+                        live.seek_before_primary_effect(loc);
+                        if !live.get().contains(place.local) {
+                            patch.push(loc);
+                        }
+                    }
+                }
+                StatementKind::Retag(_, _)
+                | StatementKind::StorageLive(_)
+                | StatementKind::StorageDead(_)
+                | StatementKind::Coverage(_)
+                | StatementKind::CopyNonOverlapping(_)
+                | StatementKind::Nop => (),
+
+                StatementKind::FakeRead(_) | StatementKind::AscribeUserType(_, _) => {
+                    bug!("{:?} not found in this MIR phase!", &statement.kind)
+                }
+            }
+        }
+    }
+
+    if patch.is_empty() {
+        return;
+    }
+
+    let bbs = body.basic_blocks_mut();
+    for Location { block, statement_index } in patch {
+        bbs[block].statements[statement_index].make_nop();
+    }
+}
+
+pub fn get_borrowed_locals(body: &Body<'_>) -> BitSet<Local> {
+    let mut b = BorrowedLocals(BitSet::new_empty(body.local_decls.len()));
+    b.visit_body(body);
+    b.0
+}
+
+struct BorrowedLocals(BitSet<Local>);
+
+impl<'tcx> Visitor<'tcx> for BorrowedLocals {
+    fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, loc: Location) {
+        self.super_rvalue(rvalue, loc);
+        match rvalue {
+            Rvalue::AddressOf(_, borrowed_place) | Rvalue::Ref(_, _, borrowed_place) => {
+                if !borrowed_place.is_indirect() {
+                    self.0.insert(borrowed_place.local);
+                }
+            }
+
+            Rvalue::Cast(..)
+            | Rvalue::ShallowInitBox(..)
+            | Rvalue::Use(..)
+            | Rvalue::Repeat(..)
+            | Rvalue::Len(..)
+            | Rvalue::BinaryOp(..)
+            | Rvalue::CheckedBinaryOp(..)
+            | Rvalue::NullaryOp(..)
+            | Rvalue::UnaryOp(..)
+            | Rvalue::Discriminant(..)
+            | Rvalue::Aggregate(..)
+            | Rvalue::ThreadLocalRef(..) => {}
+        }
+    }
+
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        self.super_terminator(terminator, location);
+
+        match terminator.kind {
+            TerminatorKind::Drop { place: dropped_place, .. } => {
+                if !dropped_place.is_indirect() {
+                    self.0.insert(dropped_place.local);
+                }
+            }
+
+            TerminatorKind::Abort
+            | TerminatorKind::DropAndReplace { .. }
+            | TerminatorKind::Assert { .. }
+            | TerminatorKind::Call { .. }
+            | TerminatorKind::FalseEdge { .. }
+            | TerminatorKind::FalseUnwind { .. }
+            | TerminatorKind::GeneratorDrop
+            | TerminatorKind::Goto { .. }
+            | TerminatorKind::Resume
+            | TerminatorKind::Return
+            | TerminatorKind::SwitchInt { .. }
+            | TerminatorKind::Unreachable
+            | TerminatorKind::Yield { .. }
+            | TerminatorKind::InlineAsm { .. } => {}
+        }
+    }
+}
+
+pub struct DeadStoreElimination;
+
+impl<'tcx> MirPass<'tcx> for DeadStoreElimination {
+    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
+        sess.mir_opt_level() >= 2
+    }
+
+    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+        let borrowed = get_borrowed_locals(body);
+        eliminate(tcx, body, &borrowed);
+    }
+}

compiler/rustc_mir_transform/src/lib.rs

@@ -49,6 +49,7 @@
 mod const_prop;
 mod const_prop_lint;
 mod coverage;
+mod dead_store_elimination;
 mod deaggregator;
 mod deduplicate_blocks;
 mod deref_separator;
@@ -481,17 +482,18 @@ fn o1<T>(x: T) -> WithMinOptLevel<T> {
             &const_prop::ConstProp,
             //
             // Const-prop runs unconditionally, but doesn't mutate the MIR at mir-opt-level=0.
+            &const_debuginfo::ConstDebugInfo,
             &o1(simplify_branches::SimplifyConstCondition::new("after-const-prop")),
             &early_otherwise_branch::EarlyOtherwiseBranch,
             &simplify_comparison_integral::SimplifyComparisonIntegral,
             &simplify_try::SimplifyArmIdentity,
             &simplify_try::SimplifyBranchSame,
+            &dead_store_elimination::DeadStoreElimination,
             &dest_prop::DestinationPropagation,
             &o1(simplify_branches::SimplifyConstCondition::new("final")),
             &o1(remove_noop_landing_pads::RemoveNoopLandingPads),
             &o1(simplify::SimplifyCfg::new("final")),
             &nrvo::RenameReturnPlace,
-            &const_debuginfo::ConstDebugInfo,
             &simplify::SimplifyLocals,
             &multiple_return_terminators::MultipleReturnTerminators,
             &deduplicate_blocks::DeduplicateBlocks,

src/test/codegen-units/item-collection/unsizing.rs

 // compile-flags:-Zprint-mono-items=eager
 // compile-flags:-Zinline-in-all-cgus
+// compile-flags:-Zmir-opt-level=0
 
 #![deny(dead_code)]
 #![feature(coerce_unsized)]

src/test/incremental/hashes/call_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/closure_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph -Zmir-opt-level=0
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -63,9 +63,9 @@ pub fn change_parameter_pattern() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, typeck, optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, typeck")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, typeck, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, typeck")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_parameter_pattern() {
     let _ = |(x,): (u32,)| x;
@@ -82,7 +82,7 @@ pub fn add_move() {
 #[cfg(not(any(cfail1,cfail4)))]
 #[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn add_move() {
     let _ = move || 1;

src/test/incremental/hashes/consts.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 
 #![allow(warnings)]
 #![feature(rustc_attrs)]

src/test/incremental/hashes/enum_constructors.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph -Zmir-opt-level=0
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -106,9 +106,9 @@ pub fn change_constructor_path_struct_like() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,optimized_mir,typeck")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,typeck")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,optimized_mir,typeck")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,typeck")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_constructor_path_struct_like() {
     let _ = Enum2::Struct {
@@ -131,9 +131,9 @@ pub fn change_constructor_variant_struct_like() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_constructor_variant_struct_like() {
     let _ = Enum2::Struct2 {
@@ -221,12 +221,12 @@ pub fn change_constructor_path_tuple_like() {
 #[cfg(not(any(cfail1,cfail4)))]
 #[rustc_clean(
     cfg="cfail2",
-    except="hir_owner_nodes,optimized_mir,typeck"
+    except="hir_owner_nodes,typeck"
 )]
 #[rustc_clean(cfg="cfail3")]
 #[rustc_clean(
     cfg="cfail5",
-    except="hir_owner_nodes,optimized_mir,typeck"
+    except="hir_owner_nodes,typeck"
 )]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_constructor_path_tuple_like() {
@@ -244,12 +244,12 @@ pub fn change_constructor_variant_tuple_like() {
 #[cfg(not(any(cfail1,cfail4)))]
 #[rustc_clean(
     cfg="cfail2",
-    except="hir_owner_nodes,optimized_mir,typeck"
+    except="hir_owner_nodes,typeck"
 )]
 #[rustc_clean(cfg="cfail3")]
 #[rustc_clean(
     cfg="cfail5",
-    except="hir_owner_nodes,optimized_mir,typeck"
+    except="hir_owner_nodes,typeck"
 )]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_constructor_variant_tuple_like() {
@@ -337,9 +337,9 @@ pub fn change_constructor_variant_c_like() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_constructor_variant_c_like() {
     let _x = Clike::C;

src/test/incremental/hashes/enum_defs.rs

@@ -12,7 +12,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/exported_vs_not.rs

 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/extern_mods.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/for_loops.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -31,9 +31,9 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -183,7 +183,7 @@ pub fn add_loop_label_to_break() {
 #[cfg(not(any(cfail1,cfail4)))]
 #[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn add_loop_label_to_break() {
     let mut _x = 0;

src/test/incremental/hashes/function_interfaces.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/if_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/indexing_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/inherent_impls.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/inline_asm.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // needs-asm-support
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/let_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -213,9 +213,9 @@ pub fn change_initializer() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes,optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_initializer() {
     let _x = 5u16;

src/test/incremental/hashes/loop_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -31,9 +31,9 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_loop_body() {
     let mut _x = 0;

src/test/incremental/hashes/match_expressions.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/panic_exprs.rs

@@ -10,7 +10,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3
-// compile-flags: -Z query-dep-graph -C debug-assertions
+// compile-flags: -Z query-dep-graph -C debug-assertions -O
 
 #![allow(warnings)]
 #![feature(rustc_attrs)]

src/test/incremental/hashes/statics.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/struct_constructors.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/struct_defs.rs

@@ -12,7 +12,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/trait_defs.rs

@@ -12,7 +12,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/trait_impls.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/type_defs.rs

@@ -12,7 +12,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 
 #![allow(warnings)]
 #![feature(rustc_attrs)]

src/test/incremental/hashes/unary_and_binary_exprs.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/while_let_loops.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans

src/test/incremental/hashes/while_loops.rs

@@ -7,7 +7,7 @@
 
 // build-pass (FIXME(62277): could be check-pass?)
 // revisions: cfail1 cfail2 cfail3 cfail4 cfail5 cfail6
-// compile-flags: -Z query-dep-graph
+// compile-flags: -Z query-dep-graph -O
 // [cfail1]compile-flags: -Zincremental-ignore-spans
 // [cfail2]compile-flags: -Zincremental-ignore-spans
 // [cfail3]compile-flags: -Zincremental-ignore-spans
@@ -31,9 +31,9 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -56,9 +56,9 @@ pub fn change_loop_condition() {
 }
 
 #[cfg(not(any(cfail1,cfail4)))]
-#[rustc_clean(cfg="cfail2", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail2", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail3")]
-#[rustc_clean(cfg="cfail5", except="hir_owner_nodes, optimized_mir")]
+#[rustc_clean(cfg="cfail5", except="hir_owner_nodes")]
 #[rustc_clean(cfg="cfail6")]
 pub fn change_loop_condition() {
     let mut _x = 0;

src/test/mir-opt/const_debuginfo.main.ConstDebugInfo.diff

@@ -99,6 +99,7 @@
           _13 = const 64_u32;              // scope 8 at $DIR/const_debuginfo.rs:21:13: 21:22
           StorageDead(_15);                // scope 8 at $DIR/const_debuginfo.rs:21:21: 21:22
           StorageDead(_14);                // scope 8 at $DIR/const_debuginfo.rs:21:21: 21:22
+          nop;                             // scope 0 at $DIR/const_debuginfo.rs:8:11: 22:2
           StorageDead(_13);                // scope 8 at $DIR/const_debuginfo.rs:22:1: 22:2
           StorageDead(_12);                // scope 7 at $DIR/const_debuginfo.rs:22:1: 22:2
           StorageDead(_11);                // scope 6 at $DIR/const_debuginfo.rs:22:1: 22:2

src/test/mir-opt/const_prop/optimizes_into_variable.main.SimplifyLocals.after.32bit.mir

@@ -17,11 +17,8 @@ fn main() -> () {
 
     bb0: {
         StorageLive(_1);                 // scope 0 at $DIR/optimizes_into_variable.rs:12:9: 12:10
-        _1 = const 4_i32;                // scope 0 at $DIR/optimizes_into_variable.rs:12:13: 12:18
         StorageLive(_2);                 // scope 1 at $DIR/optimizes_into_variable.rs:13:9: 13:10
-        _2 = const 3_i32;                // scope 1 at $DIR/optimizes_into_variable.rs:13:13: 13:34
         StorageLive(_3);                 // scope 2 at $DIR/optimizes_into_variable.rs:14:9: 14:10
-        _3 = const 42_u32;               // scope 2 at $DIR/optimizes_into_variable.rs:14:13: 14:38
         StorageDead(_3);                 // scope 2 at $DIR/optimizes_into_variable.rs:15:1: 15:2
         StorageDead(_2);                 // scope 1 at $DIR/optimizes_into_variable.rs:15:1: 15:2
         StorageDead(_1);                 // scope 0 at $DIR/optimizes_into_variable.rs:15:1: 15:2

src/test/mir-opt/const_prop/optimizes_into_variable.main.SimplifyLocals.after.64bit.mir

@@ -17,11 +17,8 @@ fn main() -> () {
 
     bb0: {
         StorageLive(_1);                 // scope 0 at $DIR/optimizes_into_variable.rs:12:9: 12:10
-        _1 = const 4_i32;                // scope 0 at $DIR/optimizes_into_variable.rs:12:13: 12:18
         StorageLive(_2);                 // scope 1 at $DIR/optimizes_into_variable.rs:13:9: 13:10
-        _2 = const 3_i32;                // scope 1 at $DIR/optimizes_into_variable.rs:13:13: 13:34
         StorageLive(_3);                 // scope 2 at $DIR/optimizes_into_variable.rs:14:9: 14:10
-        _3 = const 42_u32;               // scope 2 at $DIR/optimizes_into_variable.rs:14:13: 14:38
         StorageDead(_3);                 // scope 2 at $DIR/optimizes_into_variable.rs:15:1: 15:2
         StorageDead(_2);                 // scope 1 at $DIR/optimizes_into_variable.rs:15:1: 15:2
         StorageDead(_1);                 // scope 0 at $DIR/optimizes_into_variable.rs:15:1: 15:2

src/test/mir-opt/dead-store-elimination/cycle.cycle.DeadStoreElimination.diff

+- // MIR for `cycle` before DeadStoreElimination
++ // MIR for `cycle` after DeadStoreElimination
+  
+  fn cycle(_1: i32, _2: i32, _3: i32) -> () {
+      debug x => _1;                       // in scope 0 at $DIR/cycle.rs:9:10: 9:15
+      debug y => _2;                       // in scope 0 at $DIR/cycle.rs:9:22: 9:27
+      debug z => _3;                       // in scope 0 at $DIR/cycle.rs:9:34: 9:39
+      let mut _0: ();                      // return place in scope 0 at $DIR/cycle.rs:9:46: 9:46
+      let mut _4: ();                      // in scope 0 at $DIR/cycle.rs:9:1: 18:2
+      let mut _5: bool;                    // in scope 0 at $DIR/cycle.rs:12:11: 12:17
+      let _6: i32;                         // in scope 0 at $DIR/cycle.rs:13:13: 13:17
+      let mut _7: i32;                     // in scope 0 at $DIR/cycle.rs:14:13: 14:14
+      let mut _8: i32;                     // in scope 0 at $DIR/cycle.rs:15:13: 15:14
+      let mut _9: i32;                     // in scope 0 at $DIR/cycle.rs:16:13: 16:17
+      let mut _10: !;                      // in scope 0 at $DIR/cycle.rs:12:5: 17:6
+      let _11: ();                         // in scope 0 at $DIR/cycle.rs:12:5: 17:6
+      let mut _12: !;                      // in scope 0 at $DIR/cycle.rs:12:5: 17:6
+      scope 1 {
+          debug temp => _6;                // in scope 1 at $DIR/cycle.rs:13:13: 13:17
+      }
+  
+      bb0: {
+          goto -> bb1;                     // scope 0 at $DIR/cycle.rs:12:5: 17:6
+      }
+  
+      bb1: {
+          StorageLive(_5);                 // scope 0 at $DIR/cycle.rs:12:11: 12:17
+          _5 = cond() -> bb2;              // scope 0 at $DIR/cycle.rs:12:11: 12:17
+                                           // mir::Constant
+                                           // + span: $DIR/cycle.rs:12:11: 12:15
+                                           // + literal: Const { ty: fn() -> bool {cond}, val: Value(Scalar(<ZST>)) }
+      }
+  
+      bb2: {
+          switchInt(move _5) -> [false: bb4, otherwise: bb3]; // scope 0 at $DIR/cycle.rs:12:11: 12:17
+      }
+  
+      bb3: {
+          StorageLive(_6);                 // scope 0 at $DIR/cycle.rs:13:13: 13:17
+-         _6 = _3;                         // scope 0 at $DIR/cycle.rs:13:20: 13:21
++         nop;                             // scope 0 at $DIR/cycle.rs:13:20: 13:21
+          StorageLive(_7);                 // scope 1 at $DIR/cycle.rs:14:13: 14:14
+-         _7 = _2;                         // scope 1 at $DIR/cycle.rs:14:13: 14:14
+-         _3 = move _7;                    // scope 1 at $DIR/cycle.rs:14:9: 14:14
++         nop;                             // scope 1 at $DIR/cycle.rs:14:13: 14:14
++         nop;                             // scope 1 at $DIR/cycle.rs:14:9: 14:14
+          StorageDead(_7);                 // scope 1 at $DIR/cycle.rs:14:13: 14:14
+          StorageLive(_8);                 // scope 1 at $DIR/cycle.rs:15:13: 15:14
+-         _8 = _1;                         // scope 1 at $DIR/cycle.rs:15:13: 15:14
+-         _2 = move _8;                    // scope 1 at $DIR/cycle.rs:15:9: 15:14
++         nop;                             // scope 1 at $DIR/cycle.rs:15:13: 15:14
++         nop;                             // scope 1 at $DIR/cycle.rs:15:9: 15:14
+          StorageDead(_8);                 // scope 1 at $DIR/cycle.rs:15:13: 15:14
+          StorageLive(_9);                 // scope 1 at $DIR/cycle.rs:16:13: 16:17
+-         _9 = _6;                         // scope 1 at $DIR/cycle.rs:16:13: 16:17
+-         _1 = move _9;                    // scope 1 at $DIR/cycle.rs:16:9: 16:17
++         nop;                             // scope 1 at $DIR/cycle.rs:16:13: 16:17
++         nop;                             // scope 1 at $DIR/cycle.rs:16:9: 16:17
+          StorageDead(_9);                 // scope 1 at $DIR/cycle.rs:16:16: 16:17
+-         _4 = const ();                   // scope 0 at $DIR/cycle.rs:12:18: 17:6
++         nop;                             // scope 0 at $DIR/cycle.rs:12:18: 17:6
+          StorageDead(_6);                 // scope 0 at $DIR/cycle.rs:17:5: 17:6
+          StorageDead(_5);                 // scope 0 at $DIR/cycle.rs:17:5: 17:6
+          goto -> bb1;                     // scope 0 at $DIR/cycle.rs:12:5: 17:6
+      }
+  
+      bb4: {
+          StorageLive(_11);                // scope 0 at $DIR/cycle.rs:12:5: 17:6
+          _0 = const ();                   // scope 0 at $DIR/cycle.rs:12:5: 17:6
+          StorageDead(_11);                // scope 0 at $DIR/cycle.rs:17:5: 17:6
+          StorageDead(_5);                 // scope 0 at $DIR/cycle.rs:17:5: 17:6
+          return;                          // scope 0 at $DIR/cycle.rs:18:2: 18:2
+      }
+  }
+  

src/test/mir-opt/dead-store-elimination/cycle.rs

+// unit-test: DeadStoreElimination
+
+#[inline(never)]
+fn cond() -> bool {
+    false
+}
+
+// EMIT_MIR cycle.cycle.DeadStoreElimination.diff
+fn cycle(mut x: i32, mut y: i32, mut z: i32) {
+    // This example is interesting because the non-transitive version of `MaybeLiveLocals` would
+    // report that *all* of these stores are live.
+    while cond() {
+        let temp = z;
+        z = y;
+        y = x;
+        x = temp;
+    }
+}
+
+fn main() {
+    cycle(1, 2, 3);
+}

src/test/mir-opt/dead-store-elimination/provenance_soundness.pointer_to_int.DeadStoreElimination.diff

+- // MIR for `pointer_to_int` before DeadStoreElimination
++ // MIR for `pointer_to_int` after DeadStoreElimination
+  
+  fn pointer_to_int(_1: *mut i32) -> () {
+      debug p => _1;                       // in scope 0 at $DIR/provenance_soundness.rs:7:19: 7:20
+      let mut _0: ();                      // return place in scope 0 at $DIR/provenance_soundness.rs:7:32: 7:32
+      let _2: usize;                       // in scope 0 at $DIR/provenance_soundness.rs:8:9: 8:11
+      let mut _3: *mut i32;                // in scope 0 at $DIR/provenance_soundness.rs:8:14: 8:15
+      let mut _5: *mut i32;                // in scope 0 at $DIR/provenance_soundness.rs:9:14: 9:15
+      scope 1 {
+          debug _x => _2;                  // in scope 1 at $DIR/provenance_soundness.rs:8:9: 8:11
+          let _4: isize;                   // in scope 1 at $DIR/provenance_soundness.rs:9:9: 9:11
+          scope 2 {
+              debug _y => _4;              // in scope 2 at $DIR/provenance_soundness.rs:9:9: 9:11
+          }
+      }
+  
+      bb0: {
+          StorageLive(_2);                 // scope 0 at $DIR/provenance_soundness.rs:8:9: 8:11
+          StorageLive(_3);                 // scope 0 at $DIR/provenance_soundness.rs:8:14: 8:15
+          _3 = _1;                         // scope 0 at $DIR/provenance_soundness.rs:8:14: 8:15
+          _2 = move _3 as usize (Misc);    // scope 0 at $DIR/provenance_soundness.rs:8:14: 8:24
+          StorageDead(_3);                 // scope 0 at $DIR/provenance_soundness.rs:8:23: 8:24
+          StorageLive(_4);                 // scope 1 at $DIR/provenance_soundness.rs:9:9: 9:11
+          StorageLive(_5);                 // scope 1 at $DIR/provenance_soundness.rs:9:14: 9:15
+          _5 = _1;                         // scope 1 at $DIR/provenance_soundness.rs:9:14: 9:15
+          _4 = move _5 as isize (Misc);    // scope 1 at $DIR/provenance_soundness.rs:9:14: 9:24
+          StorageDead(_5);                 // scope 1 at $DIR/provenance_soundness.rs:9:23: 9:24
+          _0 = const ();                   // scope 0 at $DIR/provenance_soundness.rs:7:32: 10:2
+          StorageDead(_4);                 // scope 1 at $DIR/provenance_soundness.rs:10:1: 10:2
+          StorageDead(_2);                 // scope 0 at $DIR/provenance_soundness.rs:10:1: 10:2
+          return;                          // scope 0 at $DIR/provenance_soundness.rs:10:2: 10:2
+      }
+  }
+  

src/test/mir-opt/dead-store-elimination/provenance_soundness.retags.DeadStoreElimination.diff

+- // MIR for `retags` before DeadStoreElimination
++ // MIR for `retags` after DeadStoreElimination
+  
+  fn retags(_1: &mut i32) -> () {
+      debug _r => _1;                      // in scope 0 at $DIR/provenance_soundness.rs:13:11: 13:13
+      let mut _0: ();                      // return place in scope 0 at $DIR/provenance_soundness.rs:13:25: 13:25
+  
+      bb0: {
+          Retag([fn entry] _1);            // scope 0 at $DIR/provenance_soundness.rs:13:1: 13:27
+          _0 = const ();                   // scope 0 at $DIR/provenance_soundness.rs:13:25: 13:27
+          return;                          // scope 0 at $DIR/provenance_soundness.rs:13:27: 13:27
+      }
+  }
+  

src/test/mir-opt/dead-store-elimination/provenance_soundness.rs

+// unit-test: DeadStoreElimination
+// compile-flags: -Zmir-emit-retag
+
+// Test that we don't remove pointer to int casts or retags
+
+// EMIT_MIR provenance_soundness.pointer_to_int.DeadStoreElimination.diff
+fn pointer_to_int(p: *mut i32) {
+    let _x = p as usize;
+    let _y = p as isize;
+}
+
+// EMIT_MIR provenance_soundness.retags.DeadStoreElimination.diff
+fn retags(_r: &mut i32) {}
+
+fn main() {
+    pointer_to_int(&mut 5 as *mut _);
+    retags(&mut 5);
+}

src/test/mir-opt/dest-prop/branch.main.DestinationPropagation.diff

@@ -7,8 +7,7 @@
       let mut _3: bool;                    // in scope 0 at $DIR/branch.rs:15:16: 15:22
       let _4: i32;                         // in scope 0 at $DIR/branch.rs:18:9: 18:14
       scope 1 {
--         debug x => _1;                   // in scope 1 at $DIR/branch.rs:13:9: 13:10
-+         debug x => _2;                   // in scope 1 at $DIR/branch.rs:13:9: 13:10
+          debug x => _1;                   // in scope 1 at $DIR/branch.rs:13:9: 13:10
           let _2: i32;                     // in scope 1 at $DIR/branch.rs:15:9: 15:10
           scope 2 {
               debug y => _2;               // in scope 2 at $DIR/branch.rs:15:9: 15:10
@@ -16,18 +15,15 @@
       }
   
       bb0: {
--         StorageLive(_1);                 // scope 0 at $DIR/branch.rs:13:9: 13:10
--         _1 = val() -> bb1;               // scope 0 at $DIR/branch.rs:13:13: 13:18
-+         nop;                             // scope 0 at $DIR/branch.rs:13:9: 13:10
-+         _2 = val() -> bb1;               // scope 0 at $DIR/branch.rs:13:13: 13:18
+          StorageLive(_1);                 // scope 0 at $DIR/branch.rs:13:9: 13:10
+          _1 = val() -> bb1;               // scope 0 at $DIR/branch.rs:13:13: 13:18
                                            // mir::Constant
                                            // + span: $DIR/branch.rs:13:13: 13:16
                                            // + literal: Const { ty: fn() -> i32 {val}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
--         StorageLive(_2);                 // scope 1 at $DIR/branch.rs:15:9: 15:10
-+         nop;                             // scope 1 at $DIR/branch.rs:15:9: 15:10
+          StorageLive(_2);                 // scope 1 at $DIR/branch.rs:15:9: 15:10
           StorageLive(_3);                 // scope 1 at $DIR/branch.rs:15:16: 15:22
           _3 = cond() -> bb2;              // scope 1 at $DIR/branch.rs:15:16: 15:22
                                            // mir::Constant
@@ -40,8 +36,7 @@
       }
   
       bb3: {
--         _2 = _1;                         // scope 1 at $DIR/branch.rs:16:9: 16:10
-+         nop;                             // scope 1 at $DIR/branch.rs:16:9: 16:10
+          nop;                             // scope 1 at $DIR/branch.rs:16:9: 16:10
           goto -> bb6;                     // scope 1 at $DIR/branch.rs:15:13: 20:6
       }
   
@@ -55,18 +50,15 @@
   
       bb5: {
           StorageDead(_4);                 // scope 1 at $DIR/branch.rs:18:14: 18:15
--         _2 = _1;                         // scope 1 at $DIR/branch.rs:19:9: 19:10
-+         nop;                             // scope 1 at $DIR/branch.rs:19:9: 19:10
+          nop;                             // scope 1 at $DIR/branch.rs:19:9: 19:10
           goto -> bb6;                     // scope 1 at $DIR/branch.rs:15:13: 20:6
       }
   
       bb6: {
           StorageDead(_3);                 // scope 1 at $DIR/branch.rs:20:5: 20:6
           nop;                             // scope 0 at $DIR/branch.rs:12:11: 21:2
--         StorageDead(_2);                 // scope 1 at $DIR/branch.rs:21:1: 21:2
--         StorageDead(_1);                 // scope 0 at $DIR/branch.rs:21:1: 21:2
-+         nop;                             // scope 1 at $DIR/branch.rs:21:1: 21:2
-+         nop;                             // scope 0 at $DIR/branch.rs:21:1: 21:2
+          StorageDead(_2);                 // scope 1 at $DIR/branch.rs:21:1: 21:2
+          StorageDead(_1);                 // scope 0 at $DIR/branch.rs:21:1: 21:2
           return;                          // scope 0 at $DIR/branch.rs:21:2: 21:2
       }
   }

src/test/mir-opt/dest-prop/copy_propagation_arg.arg_src.DestinationPropagation.diff

@@ -2,7 +2,7 @@
 + // MIR for `arg_src` after DestinationPropagation
   
   fn arg_src(_1: i32) -> i32 {
-      debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:27:12: 27:17
+      debug x => const 123_i32;            // in scope 0 at $DIR/copy_propagation_arg.rs:27:12: 27:17
       let mut _0: i32;                     // return place in scope 0 at $DIR/copy_propagation_arg.rs:27:27: 27:30
       let _2: i32;                         // in scope 0 at $DIR/copy_propagation_arg.rs:28:9: 28:10
       scope 1 {
@@ -15,7 +15,7 @@
 -         _2 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:28:13: 28:14
 +         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:28:9: 28:10
 +         _0 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:28:13: 28:14
-          _1 = const 123_i32;              // scope 1 at $DIR/copy_propagation_arg.rs:29:5: 29:12
+          nop;                             // scope 1 at $DIR/copy_propagation_arg.rs:29:5: 29:12
 -         _0 = _2;                         // scope 1 at $DIR/copy_propagation_arg.rs:30:5: 30:6
 -         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:31:1: 31:2
 +         nop;                             // scope 1 at $DIR/copy_propagation_arg.rs:30:5: 30:6

src/test/mir-opt/dest-prop/copy_propagation_arg.bar.DestinationPropagation.diff

@@ -2,7 +2,7 @@
 + // MIR for `bar` after DestinationPropagation
   
   fn bar(_1: u8) -> () {
-      debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:15:8: 15:13
+      debug x => const 5_u8;               // in scope 0 at $DIR/copy_propagation_arg.rs:15:8: 15:13
       let mut _0: ();                      // return place in scope 0 at $DIR/copy_propagation_arg.rs:15:19: 15:19
       let _2: u8;                          // in scope 0 at $DIR/copy_propagation_arg.rs:16:5: 16:13
       let mut _3: u8;                      // in scope 0 at $DIR/copy_propagation_arg.rs:16:11: 16:12
@@ -20,7 +20,7 @@
       bb1: {
           StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:16:12: 16:13
           StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:16:13: 16:14
-          _1 = const 5_u8;                 // scope 0 at $DIR/copy_propagation_arg.rs:17:5: 17:10
+          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:17:5: 17:10
           nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:15:19: 18:2
           return;                          // scope 0 at $DIR/copy_propagation_arg.rs:18:2: 18:2
       }

src/test/mir-opt/dest-prop/copy_propagation_arg.baz.DestinationPropagation.diff

@@ -7,14 +7,10 @@
       let mut _2: i32;                     // in scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
   
       bb0: {
--         StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
--         _2 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
--         _1 = move _2;                    // scope 0 at $DIR/copy_propagation_arg.rs:23:5: 23:10
--         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:5: 23:10
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
+          StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
+          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
+          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:23:5: 23:10
+          StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:23:9: 23:10
           nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:21:20: 24:2
           return;                          // scope 0 at $DIR/copy_propagation_arg.rs:24:2: 24:2
       }

src/test/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.diff

@@ -8,12 +8,10 @@
       let mut _3: u8;                      // in scope 0 at $DIR/copy_propagation_arg.rs:11:15: 11:16
   
       bb0: {
--         StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
+          StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
           StorageLive(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:15: 11:16
           _3 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:11:15: 11:16
--         _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
-+         _1 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
+          _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:11:9: 11:17
                                            // mir::Constant
                                            // + span: $DIR/copy_propagation_arg.rs:11:9: 11:14
                                            // + literal: Const { ty: fn(u8) -> u8 {dummy}, val: Value(Scalar(<ZST>)) }
@@ -21,10 +19,8 @@
   
       bb1: {
           StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:16: 11:17
--         _1 = move _2;                    // scope 0 at $DIR/copy_propagation_arg.rs:11:5: 11:17
--         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:16: 11:17
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:11:5: 11:17
-+         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:11:16: 11:17
+          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:11:5: 11:17
+          StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:11:16: 11:17
           nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:9:19: 12:2
           return;                          // scope 0 at $DIR/copy_propagation_arg.rs:12:2: 12:2
       }

src/test/mir-opt/dest-prop/cycle.main.DestinationPropagation.diff

@@ -8,16 +8,13 @@
       let _5: ();                          // in scope 0 at $DIR/cycle.rs:14:5: 14:12
       let mut _6: i32;                     // in scope 0 at $DIR/cycle.rs:14:10: 14:11
       scope 1 {
--         debug x => _1;                   // in scope 1 at $DIR/cycle.rs:9:9: 9:14
-+         debug x => _4;                   // in scope 1 at $DIR/cycle.rs:9:9: 9:14
+          debug x => _1;                   // in scope 1 at $DIR/cycle.rs:9:9: 9:14
           let _2: i32;                     // in scope 1 at $DIR/cycle.rs:10:9: 10:10
           scope 2 {
--             debug y => _2;               // in scope 2 at $DIR/cycle.rs:10:9: 10:10
-+             debug y => _4;               // in scope 2 at $DIR/cycle.rs:10:9: 10:10
+              debug y => _2;               // in scope 2 at $DIR/cycle.rs:10:9: 10:10
               let _3: i32;                 // in scope 2 at $DIR/cycle.rs:11:9: 11:10
               scope 3 {
--                 debug z => _3;           // in scope 3 at $DIR/cycle.rs:11:9: 11:10
-+                 debug z => _4;           // in scope 3 at $DIR/cycle.rs:11:9: 11:10
+                  debug z => _3;           // in scope 3 at $DIR/cycle.rs:11:9: 11:10
                   scope 4 (inlined std::mem::drop::<i32>) { // at $DIR/cycle.rs:14:5: 14:12
                       debug _x => _6;      // in scope 4 at $SRC_DIR/core/src/mem/mod.rs:LL:COL
                   }
@@ -26,44 +23,30 @@
       }
   
       bb0: {
--         StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:9:9: 9:14
--         _1 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:9:17: 9:22
-+         nop;                             // scope 0 at $DIR/cycle.rs:9:9: 9:14
-+         _4 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:9:17: 9:22
+          StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:9:9: 9:14
+          _1 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:9:17: 9:22
                                            // mir::Constant
                                            // + span: $DIR/cycle.rs:9:17: 9:20
                                            // + literal: Const { ty: fn() -> i32 {val}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
--         StorageLive(_2);                 // scope 1 at $DIR/cycle.rs:10:9: 10:10
--         _2 = _1;                         // scope 1 at $DIR/cycle.rs:10:13: 10:14
--         StorageLive(_3);                 // scope 2 at $DIR/cycle.rs:11:9: 11:10
--         _3 = _2;                         // scope 2 at $DIR/cycle.rs:11:13: 11:14
--         StorageLive(_4);                 // scope 3 at $DIR/cycle.rs:12:9: 12:10
--         _4 = _3;                         // scope 3 at $DIR/cycle.rs:12:9: 12:10
--         _1 = move _4;                    // scope 3 at $DIR/cycle.rs:12:5: 12:10
--         StorageDead(_4);                 // scope 3 at $DIR/cycle.rs:12:9: 12:10
-+         nop;                             // scope 1 at $DIR/cycle.rs:10:9: 10:10
-+         nop;                             // scope 1 at $DIR/cycle.rs:10:13: 10:14
-+         nop;                             // scope 2 at $DIR/cycle.rs:11:9: 11:10
-+         nop;                             // scope 2 at $DIR/cycle.rs:11:13: 11:14
-+         nop;                             // scope 3 at $DIR/cycle.rs:12:9: 12:10
-+         nop;                             // scope 3 at $DIR/cycle.rs:12:9: 12:10
-+         nop;                             // scope 3 at $DIR/cycle.rs:12:5: 12:10
-+         nop;                             // scope 3 at $DIR/cycle.rs:12:9: 12:10
+          StorageLive(_2);                 // scope 1 at $DIR/cycle.rs:10:9: 10:10
+          nop;                             // scope 1 at $DIR/cycle.rs:10:13: 10:14
+          StorageLive(_3);                 // scope 2 at $DIR/cycle.rs:11:9: 11:10
+          nop;                             // scope 2 at $DIR/cycle.rs:11:13: 11:14
+          StorageLive(_4);                 // scope 3 at $DIR/cycle.rs:12:9: 12:10
+          nop;                             // scope 3 at $DIR/cycle.rs:12:9: 12:10
+          nop;                             // scope 3 at $DIR/cycle.rs:12:5: 12:10
+          StorageDead(_4);                 // scope 3 at $DIR/cycle.rs:12:9: 12:10
           StorageLive(_5);                 // scope 3 at $DIR/cycle.rs:14:5: 14:12
           StorageLive(_6);                 // scope 3 at $DIR/cycle.rs:14:10: 14:11
--         _6 = _1;                         // scope 3 at $DIR/cycle.rs:14:10: 14:11
-+         _6 = _4;                         // scope 3 at $DIR/cycle.rs:14:10: 14:11
+          nop;                             // scope 3 at $DIR/cycle.rs:14:10: 14:11
           StorageDead(_6);                 // scope 3 at $DIR/cycle.rs:14:11: 14:12
           StorageDead(_5);                 // scope 3 at $DIR/cycle.rs:14:12: 14:13
--         StorageDead(_3);                 // scope 2 at $DIR/cycle.rs:15:1: 15:2
--         StorageDead(_2);                 // scope 1 at $DIR/cycle.rs:15:1: 15:2
--         StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:15:1: 15:2
-+         nop;                             // scope 2 at $DIR/cycle.rs:15:1: 15:2
-+         nop;                             // scope 1 at $DIR/cycle.rs:15:1: 15:2
-+         nop;                             // scope 0 at $DIR/cycle.rs:15:1: 15:2
+          StorageDead(_3);                 // scope 2 at $DIR/cycle.rs:15:1: 15:2
+          StorageDead(_2);                 // scope 1 at $DIR/cycle.rs:15:1: 15:2
+          StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:15:1: 15:2
           return;                          // scope 0 at $DIR/cycle.rs:15:2: 15:2
       }
   }

src/test/mir-opt/dest-prop/union.main.DestinationPropagation.diff

@@ -17,30 +17,24 @@
       }
   
       bb0: {
--         StorageLive(_1);                 // scope 0 at $DIR/union.rs:13:9: 13:11
--         StorageLive(_2);                 // scope 0 at $DIR/union.rs:13:23: 13:28
--         _2 = val() -> bb1;               // scope 0 at $DIR/union.rs:13:23: 13:28
-+         nop;                             // scope 0 at $DIR/union.rs:13:9: 13:11
-+         nop;                             // scope 0 at $DIR/union.rs:13:23: 13:28
-+         (_1.0: u32) = val() -> bb1;      // scope 0 at $DIR/union.rs:13:23: 13:28
+          StorageLive(_1);                 // scope 0 at $DIR/union.rs:13:9: 13:11
+          StorageLive(_2);                 // scope 0 at $DIR/union.rs:13:23: 13:28
+          _2 = val() -> bb1;               // scope 0 at $DIR/union.rs:13:23: 13:28
                                            // mir::Constant
                                            // + span: $DIR/union.rs:13:23: 13:26
                                            // + literal: Const { ty: fn() -> u32 {val}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {
-          Deinit(_1);                      // scope 0 at $DIR/union.rs:13:14: 13:30
--         (_1.0: u32) = move _2;           // scope 0 at $DIR/union.rs:13:14: 13:30
--         StorageDead(_2);                 // scope 0 at $DIR/union.rs:13:29: 13:30
-+         nop;                             // scope 0 at $DIR/union.rs:13:14: 13:30
-+         nop;                             // scope 0 at $DIR/union.rs:13:29: 13:30
+          nop;                             // scope 0 at $DIR/union.rs:13:14: 13:30
+          nop;                             // scope 0 at $DIR/union.rs:13:14: 13:30
+          StorageDead(_2);                 // scope 0 at $DIR/union.rs:13:29: 13:30
           StorageLive(_3);                 // scope 1 at $DIR/union.rs:15:5: 15:27
           StorageLive(_4);                 // scope 1 at $DIR/union.rs:15:10: 15:26
-          _4 = (_1.0: u32);                // scope 2 at $DIR/union.rs:15:19: 15:24
+          nop;                             // scope 2 at $DIR/union.rs:15:19: 15:24
           StorageDead(_4);                 // scope 1 at $DIR/union.rs:15:26: 15:27
           StorageDead(_3);                 // scope 1 at $DIR/union.rs:15:27: 15:28
--         StorageDead(_1);                 // scope 0 at $DIR/union.rs:16:1: 16:2
-+         nop;                             // scope 0 at $DIR/union.rs:16:1: 16:2
+          StorageDead(_1);                 // scope 0 at $DIR/union.rs:16:1: 16:2
           return;                          // scope 0 at $DIR/union.rs:16:2: 16:2
       }
   }

src/test/mir-opt/issue_73223.main.PreCodegen.32bit.diff

@@ -6,33 +6,32 @@
       let _1: i32;                         // in scope 0 at $DIR/issue-73223.rs:2:9: 2:14
       let mut _2: std::option::Option<i32>; // in scope 0 at $DIR/issue-73223.rs:2:23: 2:30
       let _3: i32;                         // in scope 0 at $DIR/issue-73223.rs:3:14: 3:15
-      let mut _5: i32;                     // in scope 0 at $DIR/issue-73223.rs:7:22: 7:27
-      let mut _6: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _5: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _6: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let mut _7: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _8: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _10: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let mut _11: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _12: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _13: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _15: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _16: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _17: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _18: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _19: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _20: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _12: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _14: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _15: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _16: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _17: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _18: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _19: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       scope 1 {
           debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:2:9: 2:14
           let _4: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:7:9: 7:14
           scope 3 {
               debug _prev => _4;           // in scope 3 at $DIR/issue-73223.rs:7:9: 7:14
+              let _8: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
               let _9: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let _10: &i32;               // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let mut _21: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+              let mut _20: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
               scope 4 {
-                  debug left_val => _9;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  debug right_val => _10;  // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  let _14: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  debug left_val => _8;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  debug right_val => _9;   // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  let _13: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                   scope 5 {
-                      debug kind => _14;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                      debug kind => _13;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                   }
               }
           }
@@ -53,58 +52,50 @@
           StorageDead(_3);                 // scope 0 at $DIR/issue-73223.rs:3:20: 3:21
           StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:5:6: 5:7
           StorageLive(_4);                 // scope 1 at $DIR/issue-73223.rs:7:9: 7:14
-          StorageLive(_5);                 // scope 1 at $DIR/issue-73223.rs:7:22: 7:27
-          _5 = _1;                         // scope 1 at $DIR/issue-73223.rs:7:22: 7:27
-          Deinit(_4);                      // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          ((_4 as Some).0: i32) = move _5; // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          discriminant(_4) = 1;            // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          StorageDead(_5);                 // scope 1 at $DIR/issue-73223.rs:7:27: 7:28
+          StorageLive(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _6 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _7 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _21 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _20 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
-          _8 = _21;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_6);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_6.0: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_6.1: &i32) = move _8;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _7 = _20;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          Deinit(_5);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          (_5.0: &i32) = move _6;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          (_5.1: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _8 = (_5.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _9 = (_6.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _10 = (_6.1: &i32);              // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _9 = (_5.1: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _13 = (*_9);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _12 = Eq(move _13, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _11 = Not(move _12);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _12 = (*_8);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _11 = Eq(move _12, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          switchInt(move _11) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _10 = Not(move _11);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          switchInt(move _10) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       }
   
       bb1: {
-          StorageLive(_14);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_14);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_14) = 0;           // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_14);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_15);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_16);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _16 = _8;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _15 = _16;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_17);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _17 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _16 = _17;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _18 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _17 = _18;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_19);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _19 = _10;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _18 = _19;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_20);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_20);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_20) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _15 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _16, move _18, move _20); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          Deinit(_19);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          discriminant(_19) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _14 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _15, move _17, move _19); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(Scalar(<ZST>)) }
@@ -114,10 +105,10 @@
       }
   
       bb2: {
-          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_4);                 // scope 1 at $DIR/issue-73223.rs:9:1: 9:2
           StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:9:1: 9:2
           return;                          // scope 0 at $DIR/issue-73223.rs:9:2: 9:2

src/test/mir-opt/issue_73223.main.PreCodegen.64bit.diff

@@ -6,33 +6,32 @@
       let _1: i32;                         // in scope 0 at $DIR/issue-73223.rs:2:9: 2:14
       let mut _2: std::option::Option<i32>; // in scope 0 at $DIR/issue-73223.rs:2:23: 2:30
       let _3: i32;                         // in scope 0 at $DIR/issue-73223.rs:3:14: 3:15
-      let mut _5: i32;                     // in scope 0 at $DIR/issue-73223.rs:7:22: 7:27
-      let mut _6: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _5: (&i32, &i32);            // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _6: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let mut _7: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _8: &i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _10: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       let mut _11: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _12: bool;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _13: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _15: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _16: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _17: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _18: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let _19: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-      let mut _20: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _12: i32;                    // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _14: !;                          // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _15: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _16: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _17: &i32;                   // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let _18: &i32;                       // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+      let mut _19: std::option::Option<std::fmt::Arguments>; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       scope 1 {
           debug split => _1;               // in scope 1 at $DIR/issue-73223.rs:2:9: 2:14
           let _4: std::option::Option<i32>; // in scope 1 at $DIR/issue-73223.rs:7:9: 7:14
           scope 3 {
               debug _prev => _4;           // in scope 3 at $DIR/issue-73223.rs:7:9: 7:14
+              let _8: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
               let _9: &i32;                // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let _10: &i32;               // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-              let mut _21: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+              let mut _20: &i32;           // in scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
               scope 4 {
-                  debug left_val => _9;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  debug right_val => _10;  // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-                  let _14: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  debug left_val => _8;    // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  debug right_val => _9;   // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                  let _13: core::panicking::AssertKind; // in scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                   scope 5 {
-                      debug kind => _14;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+                      debug kind => _13;   // in scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                   }
               }
           }
@@ -53,58 +52,50 @@
           StorageDead(_3);                 // scope 0 at $DIR/issue-73223.rs:3:20: 3:21
           StorageDead(_2);                 // scope 0 at $DIR/issue-73223.rs:5:6: 5:7
           StorageLive(_4);                 // scope 1 at $DIR/issue-73223.rs:7:9: 7:14
-          StorageLive(_5);                 // scope 1 at $DIR/issue-73223.rs:7:22: 7:27
-          _5 = _1;                         // scope 1 at $DIR/issue-73223.rs:7:22: 7:27
-          Deinit(_4);                      // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          ((_4 as Some).0: i32) = move _5; // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          discriminant(_4) = 1;            // scope 1 at $DIR/issue-73223.rs:7:17: 7:28
-          StorageDead(_5);                 // scope 1 at $DIR/issue-73223.rs:7:27: 7:28
+          StorageLive(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _6 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _7 = &_1;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _21 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _20 = const main::promoted[0];   // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: &i32, val: Unevaluated(main, [], Some(promoted[0])) }
-          _8 = _21;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_6);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_6.0: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          (_6.1: &i32) = move _8;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _7 = _20;                        // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          Deinit(_5);                      // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          (_5.0: &i32) = move _6;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          (_5.1: &i32) = move _7;          // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_7);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _8 = (_5.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _9 = (_6.0: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _10 = (_6.1: &i32);              // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _9 = (_5.1: &i32);               // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _13 = (*_9);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _12 = Eq(move _13, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _11 = Not(move _12);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _12 = (*_8);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _11 = Eq(move _12, const 1_i32); // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_12);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          switchInt(move _11) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _10 = Not(move _11);             // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          switchInt(move _10) -> [false: bb2, otherwise: bb1]; // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
       }
   
       bb1: {
-          StorageLive(_14);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_14);                     // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_14) = 0;           // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_13);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageLive(_14);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_15);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_16);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _16 = _8;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _15 = _16;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_17);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _17 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _16 = _17;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_18);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _18 = _9;                        // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _17 = _18;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageLive(_19);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _19 = _10;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _18 = _19;                       // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageLive(_20);                // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          Deinit(_20);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          discriminant(_20) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          _15 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _16, move _18, move _20); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          Deinit(_19);                     // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          discriminant(_19) = 0;           // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          _14 = core::panicking::assert_failed::<i32, i32>(const core::panicking::AssertKind::Eq, move _15, move _17, move _19); // scope 5 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // mir::Constant
                                            // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL
                                            // + literal: Const { ty: for<'r, 's, 't0> fn(core::panicking::AssertKind, &'r i32, &'s i32, Option<Arguments<'t0>>) -> ! {core::panicking::assert_failed::<i32, i32>}, val: Value(Scalar(<ZST>)) }
@@ -114,10 +105,10 @@
       }
   
       bb2: {
-          StorageDead(_11);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_10);                // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_10);                // scope 4 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_9);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
-          StorageDead(_6);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_8);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
+          StorageDead(_5);                 // scope 3 at $SRC_DIR/core/src/macros/mod.rs:LL:COL
           StorageDead(_4);                 // scope 1 at $DIR/issue-73223.rs:9:1: 9:2
           StorageDead(_1);                 // scope 0 at $DIR/issue-73223.rs:9:1: 9:2
           return;                          // scope 0 at $DIR/issue-73223.rs:9:2: 9:2

src/test/mir-opt/issues/issue_59352.num_to_digit.PreCodegen.after.mir

@@ -32,7 +32,6 @@ fn num_to_digit(_1: char) -> u32 {
         StorageLive(_2);                 // scope 0 at $DIR/issue-59352.rs:14:8: 14:11
         _2 = _1;                         // scope 0 at $DIR/issue-59352.rs:14:8: 14:11
         StorageLive(_5);                 // scope 0 at $DIR/issue-59352.rs:14:8: 14:23
-        _5 = const 8_u32;                // scope 0 at $DIR/issue-59352.rs:14:8: 14:23
         StorageLive(_6);                 // scope 1 at $SRC_DIR/core/src/char/methods.rs:LL:COL
         StorageLive(_7);                 // scope 1 at $SRC_DIR/core/src/char/methods.rs:LL:COL
         StorageLive(_8);                 // scope 1 at $SRC_DIR/core/src/char/methods.rs:LL:COL

src/test/mir-opt/lower_array_len.array_bound.SimplifyLocals.diff

@@ -25,10 +25,7 @@
           StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
 -         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
 -         StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
--         _7 = _2;                         // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
 -         StorageLive(_11);                // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
--         _11 = _7;                        // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
--         _6 = move _7 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
 -         StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:7:20: 7:21
           _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27
 -         StorageDead(_11);                // scope 0 at $DIR/lower_array_len.rs:7:16: 7:27

src/test/mir-opt/lower_array_len.array_bound_mut.SimplifyLocals.diff

@@ -31,10 +31,7 @@
           StorageLive(_5);                 // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
 -         StorageLive(_6);                 // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
 -         StorageLive(_7);                 // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
--         _7 = &(*_2);                     // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
 -         StorageLive(_14);                // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
--         _14 = _7;                        // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
--         _6 = move _7 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
 -         StorageDead(_7);                 // scope 0 at $DIR/lower_array_len.rs:18:20: 18:21
           _5 = const N;                    // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27
 -         StorageDead(_14);                // scope 0 at $DIR/lower_array_len.rs:18:16: 18:27

src/test/mir-opt/lower_array_len.array_len.SimplifyLocals.diff

@@ -11,10 +11,7 @@
       bb0: {
 -         StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
 -         StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
--         _3 = _1;                         // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
 -         StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
--         _4 = _3;                         // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
--         _2 = move _3 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
 -         StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:31:7: 31:8
           _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14
 -         StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:31:5: 31:14

src/test/mir-opt/lower_array_len.array_len_by_value.SimplifyLocals.diff

@@ -11,10 +11,7 @@
       bb0: {
 -         StorageLive(_2);                 // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
 -         StorageLive(_3);                 // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
--         _3 = &_1;                        // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
 -         StorageLive(_4);                 // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
--         _4 = _3;                         // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
--         _2 = move _3 as &[u8] (Pointer(Unsize)); // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
 -         StorageDead(_3);                 // scope 0 at $DIR/lower_array_len.rs:38:7: 38:8
           _0 = const N;                    // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14
 -         StorageDead(_4);                 // scope 0 at $DIR/lower_array_len.rs:38:5: 38:14

src/test/mir-opt/separate_const_switch.too_complex.PreCodegen.after.mir

@@ -8,10 +8,9 @@ fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
     let _4: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:16:16: 16:17
     let mut _5: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:16:44: 16:45
     let _6: usize;                       // in scope 0 at $DIR/separate_const_switch.rs:17:17: 17:18
-    let mut _7: usize;                   // in scope 0 at $DIR/separate_const_switch.rs:17:42: 17:43
-    let _8: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
-    let mut _9: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:20:42: 20:43
-    let _10: usize;                      // in scope 0 at $DIR/separate_const_switch.rs:21:28: 21:29
+    let _7: i32;                         // in scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
+    let mut _8: i32;                     // in scope 0 at $DIR/separate_const_switch.rs:20:42: 20:43
+    let _9: usize;                       // in scope 0 at $DIR/separate_const_switch.rs:21:28: 21:29
     scope 1 {
         debug v => _4;                   // in scope 1 at $DIR/separate_const_switch.rs:16:16: 16:17
     }
@@ -19,10 +18,10 @@ fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
         debug r => _6;                   // in scope 2 at $DIR/separate_const_switch.rs:17:17: 17:18
     }
     scope 3 {
-        debug v => _8;                   // in scope 3 at $DIR/separate_const_switch.rs:20:31: 20:32
+        debug v => _7;                   // in scope 3 at $DIR/separate_const_switch.rs:20:31: 20:32
     }
     scope 4 {
-        debug r => _10;                  // in scope 4 at $DIR/separate_const_switch.rs:21:28: 21:29
+        debug r => _9;                   // in scope 4 at $DIR/separate_const_switch.rs:21:28: 21:29
     }
 
     bb0: {
@@ -33,19 +32,11 @@ fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
 
     bb1: {
         StorageLive(_6);                 // scope 0 at $DIR/separate_const_switch.rs:17:17: 17:18
-        _6 = ((_1 as Err).0: usize);     // scope 0 at $DIR/separate_const_switch.rs:17:17: 17:18
-        StorageLive(_7);                 // scope 2 at $DIR/separate_const_switch.rs:17:42: 17:43
-        _7 = _6;                         // scope 2 at $DIR/separate_const_switch.rs:17:42: 17:43
-        Deinit(_2);                      // scope 2 at $DIR/separate_const_switch.rs:17:23: 17:44
-        ((_2 as Break).0: usize) = move _7; // scope 2 at $DIR/separate_const_switch.rs:17:23: 17:44
-        discriminant(_2) = 1;            // scope 2 at $DIR/separate_const_switch.rs:17:23: 17:44
-        StorageDead(_7);                 // scope 2 at $DIR/separate_const_switch.rs:17:43: 17:44
         StorageDead(_6);                 // scope 0 at $DIR/separate_const_switch.rs:17:43: 17:44
-        StorageLive(_10);                // scope 0 at $DIR/separate_const_switch.rs:21:28: 21:29
-        _10 = ((_2 as Break).0: usize);  // scope 0 at $DIR/separate_const_switch.rs:21:28: 21:29
+        StorageLive(_9);                 // scope 0 at $DIR/separate_const_switch.rs:21:28: 21:29
         Deinit(_0);                      // scope 4 at $DIR/separate_const_switch.rs:21:34: 21:38
         discriminant(_0) = 0;            // scope 4 at $DIR/separate_const_switch.rs:21:34: 21:38
-        StorageDead(_10);                // scope 0 at $DIR/separate_const_switch.rs:21:37: 21:38
+        StorageDead(_9);                 // scope 0 at $DIR/separate_const_switch.rs:21:37: 21:38
         goto -> bb3;                     // scope 0 at $DIR/separate_const_switch.rs:21:37: 21:38
     }
 
@@ -59,15 +50,15 @@ fn too_complex(_1: Result<i32, usize>) -> Option<i32> {
         discriminant(_2) = 0;            // scope 1 at $DIR/separate_const_switch.rs:16:22: 16:46
         StorageDead(_5);                 // scope 1 at $DIR/separate_const_switch.rs:16:45: 16:46
         StorageDead(_4);                 // scope 0 at $DIR/separate_const_switch.rs:16:45: 16:46
-        StorageLive(_8);                 // scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
-        _8 = ((_2 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
-        StorageLive(_9);                 // scope 3 at $DIR/separate_const_switch.rs:20:42: 20:43
-        _9 = _8;                         // scope 3 at $DIR/separate_const_switch.rs:20:42: 20:43
+        StorageLive(_7);                 // scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
+        _7 = ((_2 as Continue).0: i32);  // scope 0 at $DIR/separate_const_switch.rs:20:31: 20:32
+        StorageLive(_8);                 // scope 3 at $DIR/separate_const_switch.rs:20:42: 20:43
+        _8 = _7;                         // scope 3 at $DIR/separate_const_switch.rs:20:42: 20:43
         Deinit(_0);                      // scope 3 at $DIR/separate_const_switch.rs:20:37: 20:44
-        ((_0 as Some).0: i32) = move _9; // scope 3 at $DIR/separate_const_switch.rs:20:37: 20:44
+        ((_0 as Some).0: i32) = move _8; // scope 3 at $DIR/separate_const_switch.rs:20:37: 20:44
         discriminant(_0) = 1;            // scope 3 at $DIR/separate_const_switch.rs:20:37: 20:44
-        StorageDead(_9);                 // scope 3 at $DIR/separate_const_switch.rs:20:43: 20:44
-        StorageDead(_8);                 // scope 0 at $DIR/separate_const_switch.rs:20:43: 20:44
+        StorageDead(_8);                 // scope 3 at $DIR/separate_const_switch.rs:20:43: 20:44
+        StorageDead(_7);                 // scope 0 at $DIR/separate_const_switch.rs:20:43: 20:44
         goto -> bb3;                     // scope 0 at $DIR/separate_const_switch.rs:20:43: 20:44
     }
 

src/test/mir-opt/simplify-locals.rs

-// compile-flags: -C overflow-checks=off
+// unit-test: SimplifyLocals
 
 #![feature(box_syntax)]
 #![feature(thread_local)]

src/test/mir-opt/simplify_locals.c.SimplifyLocals.diff

@@ -20,11 +20,12 @@
 -         StorageLive(_3);                 // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
 -         StorageLive(_4);                 // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
 -         _4 = &_1;                        // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
--         _3 = _4;                         // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
+-         _3 = &(*_4);                     // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
 -         _2 = move _3 as &[u8] (Pointer(Unsize)); // scope 1 at $DIR/simplify-locals.rs:16:20: 16:26
 -         StorageDead(_3);                 // scope 1 at $DIR/simplify-locals.rs:16:25: 16:26
 -         StorageDead(_4);                 // scope 1 at $DIR/simplify-locals.rs:16:26: 16:27
 -         StorageDead(_2);                 // scope 1 at $DIR/simplify-locals.rs:16:26: 16:27
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:13:8: 17:2
           StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:17:1: 17:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:17:2: 17:2
       }

src/test/mir-opt/simplify_locals.d1.SimplifyLocals.diff

@@ -12,6 +12,7 @@
 -         Deinit(_1);                      // scope 0 at $DIR/simplify-locals.rs:22:13: 22:17
 -         discriminant(_1) = 0;            // scope 0 at $DIR/simplify-locals.rs:22:13: 22:17
 -         StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:22:17: 22:18
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:20:9: 23:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:23:2: 23:2
       }
   }

src/test/mir-opt/simplify_locals.d2.SimplifyLocals.diff

@@ -17,17 +17,12 @@
 -         discriminant(_3) = 0;            // scope 0 at $DIR/simplify-locals.rs:28:11: 28:15
 -         Deinit(_2);                      // scope 0 at $DIR/simplify-locals.rs:28:6: 28:16
 -         (_2.0: i32) = const 10_i32;      // scope 0 at $DIR/simplify-locals.rs:28:6: 28:16
--         (_2.1: E) = const E::A;          // scope 0 at $DIR/simplify-locals.rs:28:6: 28:16
--                                          // mir::Constant
--                                          // + span: $DIR/simplify-locals.rs:28:6: 28:16
--                                          // + literal: Const { ty: E, val: Value(Scalar(0x00)) }
+-         (_2.1: E) = move _3;             // scope 0 at $DIR/simplify-locals.rs:28:6: 28:16
 -         StorageDead(_3);                 // scope 0 at $DIR/simplify-locals.rs:28:15: 28:16
--         (_2.1: E) = const E::B;          // scope 0 at $DIR/simplify-locals.rs:28:5: 28:26
--                                          // mir::Constant
--                                          // + span: $DIR/simplify-locals.rs:28:5: 28:26
--                                          // + literal: Const { ty: E, val: Value(Scalar(0x01)) }
+-         (_2.1: E) = move _1;             // scope 0 at $DIR/simplify-locals.rs:28:5: 28:26
 -         StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:28:25: 28:26
 -         StorageDead(_2);                 // scope 0 at $DIR/simplify-locals.rs:28:26: 28:27
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:26:9: 29:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:29:2: 29:2
       }
   }

src/test/mir-opt/simplify_locals.r.SimplifyLocals.diff

@@ -23,6 +23,7 @@
 -         StorageLive(_3);                 // scope 2 at $DIR/simplify-locals.rs:36:13: 36:19
 -         _3 = &mut _1;                    // scope 2 at $DIR/simplify-locals.rs:36:13: 36:19
 -         StorageDead(_3);                 // scope 2 at $DIR/simplify-locals.rs:36:19: 36:20
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:32:8: 37:2
           StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:37:1: 37:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:37:2: 37:2
       }

src/test/mir-opt/simplify_locals.t1.SimplifyLocals.diff

@@ -15,6 +15,7 @@
 -         _1 = (*_2);                      // scope 1 at $DIR/simplify-locals.rs:44:14: 44:15
 -         StorageDead(_2);                 // scope 0 at $DIR/simplify-locals.rs:44:17: 44:18
 -         StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:44:17: 44:18
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:42:9: 45:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:45:2: 45:2
       }
   }

src/test/mir-opt/simplify_locals.t2.SimplifyLocals.diff

@@ -15,6 +15,7 @@
 -         _1 = &mut (*_2);                 // scope 1 at $DIR/simplify-locals.rs:50:14: 50:20
 -         StorageDead(_2);                 // scope 0 at $DIR/simplify-locals.rs:50:22: 50:23
 -         StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:50:22: 50:23
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:48:9: 51:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:51:2: 51:2
       }
   }

src/test/mir-opt/simplify_locals.t3.SimplifyLocals.diff

@@ -19,6 +19,7 @@
 -         StorageDead(_3);                 // scope 0 at $DIR/simplify-locals.rs:56:23: 56:24
 -         StorageDead(_2);                 // scope 0 at $DIR/simplify-locals.rs:56:23: 56:24
 -         StorageDead(_1);                 // scope 0 at $DIR/simplify-locals.rs:56:23: 56:24
+          _0 = const ();                   // scope 0 at $DIR/simplify-locals.rs:54:9: 57:2
           return;                          // scope 0 at $DIR/simplify-locals.rs:57:2: 57:2
       }
   }

src/test/mir-opt/simplify_locals_removes_unused_consts.main.SimplifyLocals.diff

@@ -47,10 +47,6 @@
 -         StorageLive(_9);                 // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:34
 -         StorageLive(_10);                // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:30
 -         StorageLive(_11);                // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:28
--         Deinit(_11);                     // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:28
--         (_11.0: u8) = const 40_u8;       // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:28
--         _10 = const 40_u8;               // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:30
--         _9 = const 42_u8;                // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:12: 16:34
 -         StorageDead(_10);                // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:33: 16:34
 -         _8 = use_u8(const 42_u8) -> bb2; // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:16:5: 16:35
 +         StorageDead(_1);                 // scope 1 at $DIR/simplify-locals-removes-unused-consts.rs:14:22: 14:23

src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.32bit.diff

@@ -15,8 +15,6 @@
       }
   
       bb0: {
--         _5 = const false;                // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
--         _5 = const true;                 // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
           _2 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
           switchInt(move _2) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:5: 4:12
       }
@@ -35,7 +33,6 @@
       }
   
       bb3: {
--         _6 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:8:1: 8:2
           return;                          // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:8:2: 8:2
       }
   }

src/test/mir-opt/simplify_locals_removes_unused_discriminant_reads.map.SimplifyLocals.64bit.diff

@@ -15,8 +15,6 @@
       }
   
       bb0: {
--         _5 = const false;                // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
--         _5 = const true;                 // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
           _2 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:11: 4:12
           switchInt(move _2) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:4:5: 4:12
       }
@@ -35,7 +33,6 @@
       }
   
       bb3: {
--         _6 = discriminant(_1);           // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:8:1: 8:2
           return;                          // scope 0 at $DIR/simplify-locals-removes-unused-discriminant-reads.rs:8:2: 8:2
       }
   }

src/test/mir-opt/simplify_try.try_identity.DestinationPropagation.diff

@@ -19,15 +19,12 @@
 +         debug y => ((_0 as Ok).0: u32);  // in scope 1 at $DIR/simplify_try.rs:21:9: 21:10
       }
       scope 2 {
--         debug e => _6;                   // in scope 2 at $DIR/simplify_try.rs:22:13: 22:14
-+         debug e => ((_0 as Err).0: i32); // in scope 2 at $DIR/simplify_try.rs:22:13: 22:14
+          debug e => _6;                   // in scope 2 at $DIR/simplify_try.rs:22:13: 22:14
           scope 5 (inlined <i32 as From<i32>>::from) { // at $DIR/simplify_try.rs:22:37: 22:50
--             debug t => _9;               // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-+             debug t => ((_0 as Err).0: i32); // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+              debug t => _9;               // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
           }
           scope 6 (inlined from_error::<u32, i32>) { // at $DIR/simplify_try.rs:22:26: 22:51
--             debug e => _8;               // in scope 6 at $DIR/simplify_try.rs:12:21: 12:22
-+             debug e => ((_0 as Err).0: i32); // in scope 6 at $DIR/simplify_try.rs:12:21: 12:22
+              debug e => _8;               // in scope 6 at $DIR/simplify_try.rs:12:21: 12:22
           }
       }
       scope 3 {
@@ -83,30 +80,20 @@
       }
   
       bb2: {
--         StorageLive(_6);                 // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
--         _6 = ((_3 as Err).0: i32);       // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
--         StorageLive(_8);                 // scope 2 at $DIR/simplify_try.rs:22:37: 22:50
--         StorageLive(_9);                 // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
--         _9 = _6;                         // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
--         _8 = move _9;                    // scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
--         StorageDead(_9);                 // scope 2 at $DIR/simplify_try.rs:22:49: 22:50
--         ((_0 as Err).0: i32) = move _8;  // scope 6 at $DIR/simplify_try.rs:13:9: 13:10
-+         nop;                             // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
-+         ((_0 as Err).0: i32) = ((_3 as Err).0: i32); // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
-+         nop;                             // scope 2 at $DIR/simplify_try.rs:22:37: 22:50
-+         nop;                             // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
-+         nop;                             // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
-+         nop;                             // scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
-+         nop;                             // scope 2 at $DIR/simplify_try.rs:22:49: 22:50
-+         nop;                             // scope 6 at $DIR/simplify_try.rs:13:9: 13:10
+          StorageLive(_6);                 // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
+          nop;                             // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
+          StorageLive(_8);                 // scope 2 at $DIR/simplify_try.rs:22:37: 22:50
+          StorageLive(_9);                 // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
+          nop;                             // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
+          nop;                             // scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+          StorageDead(_9);                 // scope 2 at $DIR/simplify_try.rs:22:49: 22:50
+          nop;                             // scope 6 at $DIR/simplify_try.rs:13:9: 13:10
           Deinit(_0);                      // scope 6 at $DIR/simplify_try.rs:13:5: 13:11
           discriminant(_0) = 1;            // scope 6 at $DIR/simplify_try.rs:13:5: 13:11
--         StorageDead(_8);                 // scope 2 at $DIR/simplify_try.rs:22:50: 22:51
--         StorageDead(_6);                 // scope 0 at $DIR/simplify_try.rs:22:50: 22:51
+          StorageDead(_8);                 // scope 2 at $DIR/simplify_try.rs:22:50: 22:51
+          StorageDead(_6);                 // scope 0 at $DIR/simplify_try.rs:22:50: 22:51
 -         StorageDead(_3);                 // scope 0 at $DIR/simplify_try.rs:24:6: 24:7
 -         StorageDead(_2);                 // scope 0 at $DIR/simplify_try.rs:26:1: 26:2
-+         nop;                             // scope 2 at $DIR/simplify_try.rs:22:50: 22:51
-+         nop;                             // scope 0 at $DIR/simplify_try.rs:22:50: 22:51
 +         nop;                             // scope 0 at $DIR/simplify_try.rs:24:6: 24:7
 +         nop;                             // scope 0 at $DIR/simplify_try.rs:26:1: 26:2
           return;                          // scope 0 at $DIR/simplify_try.rs:26:2: 26:2

src/test/mir-opt/simplify_try.try_identity.SimplifyLocals.after.mir

@@ -5,16 +5,19 @@ fn try_identity(_1: Result<u32, i32>) -> Result<u32, i32> {
     let mut _0: std::result::Result<u32, i32>; // return place in scope 0 at $DIR/simplify_try.rs:20:41: 20:57
     let mut _2: std::result::Result<u32, i32>; // in scope 0 at $DIR/simplify_try.rs:21:19: 21:33
     let mut _3: isize;                   // in scope 0 at $DIR/simplify_try.rs:22:9: 22:15
+    let _4: i32;                         // in scope 0 at $DIR/simplify_try.rs:22:13: 22:14
+    let mut _5: i32;                     // in scope 0 at $DIR/simplify_try.rs:22:37: 22:50
+    let mut _6: i32;                     // in scope 0 at $DIR/simplify_try.rs:22:48: 22:49
     scope 1 {
         debug y => ((_0 as Ok).0: u32);  // in scope 1 at $DIR/simplify_try.rs:21:9: 21:10
     }
     scope 2 {
-        debug e => ((_0 as Err).0: i32); // in scope 2 at $DIR/simplify_try.rs:22:13: 22:14
+        debug e => _4;                   // in scope 2 at $DIR/simplify_try.rs:22:13: 22:14
         scope 5 (inlined <i32 as From<i32>>::from) { // at $DIR/simplify_try.rs:22:37: 22:50
-            debug t => ((_0 as Err).0: i32); // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
+            debug t => _6;               // in scope 5 at $SRC_DIR/core/src/convert/mod.rs:LL:COL
         }
         scope 6 (inlined from_error::<u32, i32>) { // at $DIR/simplify_try.rs:22:26: 22:51
-            debug e => ((_0 as Err).0: i32); // in scope 6 at $DIR/simplify_try.rs:12:21: 12:22
+            debug e => _5;               // in scope 6 at $DIR/simplify_try.rs:12:21: 12:22
         }
     }
     scope 3 {
@@ -38,9 +41,14 @@ fn try_identity(_1: Result<u32, i32>) -> Result<u32, i32> {
     }
 
     bb2: {
-        ((_0 as Err).0: i32) = ((_2 as Err).0: i32); // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
+        StorageLive(_4);                 // scope 0 at $DIR/simplify_try.rs:22:13: 22:14
+        StorageLive(_5);                 // scope 2 at $DIR/simplify_try.rs:22:37: 22:50
+        StorageLive(_6);                 // scope 2 at $DIR/simplify_try.rs:22:48: 22:49
+        StorageDead(_6);                 // scope 2 at $DIR/simplify_try.rs:22:49: 22:50
         Deinit(_0);                      // scope 6 at $DIR/simplify_try.rs:13:5: 13:11
         discriminant(_0) = 1;            // scope 6 at $DIR/simplify_try.rs:13:5: 13:11
+        StorageDead(_5);                 // scope 2 at $DIR/simplify_try.rs:22:50: 22:51
+        StorageDead(_4);                 // scope 0 at $DIR/simplify_try.rs:22:50: 22:51
         return;                          // scope 0 at $DIR/simplify_try.rs:26:2: 26:2
     }
 }

src/test/mir-opt/tls-access.rs

@@ -11,3 +11,4 @@ fn main() {
 }
 
 // EMIT_MIR tls_access.main.SimplifyCfg-final.after.mir
+// compile-flags: -Zmir-opt-level=0

src/test/mir-opt/tls_access.main.SimplifyCfg-final.after.mir

@@ -14,8 +14,6 @@ fn main() -> () {
     bb0: {
         StorageLive(_1);                 // scope 1 at $DIR/tls-access.rs:8:13: 8:14
         StorageLive(_2);                 // scope 1 at $DIR/tls-access.rs:8:18: 8:21
-        _2 = &/*tls*/ mut FOO;           // scope 1 at $DIR/tls-access.rs:8:18: 8:21
-        _1 = &(*_2);                     // scope 1 at $DIR/tls-access.rs:8:17: 8:21
         StorageLive(_3);                 // scope 2 at $DIR/tls-access.rs:9:9: 9:12
         _3 = &/*tls*/ mut FOO;           // scope 2 at $DIR/tls-access.rs:9:9: 9:12
         (*_3) = const 42_u8;             // scope 2 at $DIR/tls-access.rs:9:9: 9:17

src/test/mir-opt/uninhabited_enum.process_never.SimplifyLocals.after.mir

@@ -12,7 +12,6 @@ fn process_never(_1: *const !) -> () {
 
     bb0: {
         StorageLive(_2);                 // scope 0 at $DIR/uninhabited-enum.rs:8:8: 8:14
-        _2 = &(*_1);                     // scope 2 at $DIR/uninhabited-enum.rs:8:26: 8:33
         StorageDead(_2);                 // scope 0 at $DIR/uninhabited-enum.rs:9:1: 9:2
         unreachable;                     // scope 0 at $DIR/uninhabited-enum.rs:7:39: 9:2
     }

src/test/mir-opt/uninhabited_enum.process_void.SimplifyLocals.after.mir

@@ -12,7 +12,6 @@ fn process_void(_1: *const Void) -> () {
 
     bb0: {
         StorageLive(_2);                 // scope 0 at $DIR/uninhabited-enum.rs:14:8: 14:14
-        _2 = &(*_1);                     // scope 2 at $DIR/uninhabited-enum.rs:14:26: 14:33
         StorageDead(_2);                 // scope 0 at $DIR/uninhabited-enum.rs:17:1: 17:2
         return;                          // scope 0 at $DIR/uninhabited-enum.rs:17:2: 17:2
     }

src/test/mir-opt/unusual-item-types.rs

 // Test that we don't ICE when trying to dump MIR for unusual item types and
 // that we don't create filenames containing `<` and `>`
-
+// compile-flags: -Zmir-opt-level=0
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
 
 struct A;

src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.32bit.mir

@@ -9,7 +9,6 @@ fn change_loop_body() -> () {
 
     bb0: {
         StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
-        _1 = const 0_i32;                // scope 0 at $DIR/while_let_loops.rs:6:18: 6:19
         StorageDead(_1);                 // scope 0 at $DIR/while_let_loops.rs:11:1: 11:2
         return;                          // scope 0 at $DIR/while_let_loops.rs:11:2: 11:2
     }

src/test/mir-opt/while_let_loops.change_loop_body.PreCodegen.after.64bit.mir

@@ -9,7 +9,6 @@ fn change_loop_body() -> () {
 
     bb0: {
         StorageLive(_1);                 // scope 0 at $DIR/while_let_loops.rs:6:9: 6:15
-        _1 = const 0_i32;                // scope 0 at $DIR/while_let_loops.rs:6:18: 6:19
         StorageDead(_1);                 // scope 0 at $DIR/while_let_loops.rs:11:1: 11:2
         return;                          // scope 0 at $DIR/while_let_loops.rs:11:2: 11:2
     }