Merge from rustc

1 files changed, 23 insertions, 25 deletions

diff --git a/compiler/rustc_mir_transform/src/simplify.rs b/compiler/rustc_mir_transform/src/simplify.rs
index cb8e1dfda98..7ed43547e11 100644
--- a/compiler/rustc_mir_transform/src/simplify.rs
+++ b/compiler/rustc_mir_transform/src/simplify.rs
@@ -381,23 +381,33 @@ impl<'tcx> crate::MirPass<'tcx> for SimplifyLocals {
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         trace!("running SimplifyLocals on {:?}", body.source);
-        simplify_locals(body, tcx);
-    }
-}
 
-pub(super) fn remove_unused_definitions<'tcx>(body: &mut Body<'tcx>) {
-    // First, we're going to get a count of *actual* uses for every `Local`.
-    let mut used_locals = UsedLocals::new(body);
+        // First, we're going to get a count of *actual* uses for every `Local`.
+        let mut used_locals = UsedLocals::new(body);
 
-    // Next, we're going to remove any `Local` with zero actual uses. When we remove those
-    // `Locals`, we're also going to subtract any uses of other `Locals` from the `used_locals`
-    // count. For example, if we removed `_2 = discriminant(_1)`, then we'll subtract one from
-    // `use_counts[_1]`. That in turn might make `_1` unused, so we loop until we hit a
-    // fixedpoint where there are no more unused locals.
-    remove_unused_definitions_helper(&mut used_locals, body);
+        // Next, we're going to remove any `Local` with zero actual uses. When we remove those
+        // `Locals`, we're also going to subtract any uses of other `Locals` from the `used_locals`
+        // count. For example, if we removed `_2 = discriminant(_1)`, then we'll subtract one from
+        // `use_counts[_1]`. That in turn might make `_1` unused, so we loop until we hit a
+        // fixedpoint where there are no more unused locals.
+        remove_unused_definitions_helper(&mut used_locals, body);
+
+        // Finally, we'll actually do the work of shrinking `body.local_decls` and remapping the
+        // `Local`s.
+        let map = make_local_map(&mut body.local_decls, &used_locals);
+
+        // Only bother running the `LocalUpdater` if we actually found locals to remove.
+        if map.iter().any(Option::is_none) {
+            // Update references to all vars and tmps now
+            let mut updater = LocalUpdater { map, tcx };
+            updater.visit_body_preserves_cfg(body);
+
+            body.local_decls.shrink_to_fit();
+        }
+    }
 }
 
-fn simplify_locals<'tcx>(body: &mut Body<'tcx>, tcx: TyCtxt<'tcx>) {
+pub(super) fn remove_unused_definitions<'tcx>(body: &mut Body<'tcx>) {
     // First, we're going to get a count of *actual* uses for every `Local`.
     let mut used_locals = UsedLocals::new(body);
 
@@ -407,18 +417,6 @@ fn simplify_locals<'tcx>(body: &mut Body<'tcx>, tcx: TyCtxt<'tcx>) {
     // `use_counts[_1]`. That in turn might make `_1` unused, so we loop until we hit a
     // fixedpoint where there are no more unused locals.
     remove_unused_definitions_helper(&mut used_locals, body);
-
-    // Finally, we'll actually do the work of shrinking `body.local_decls` and remapping the `Local`s.
-    let map = make_local_map(&mut body.local_decls, &used_locals);
-
-    // Only bother running the `LocalUpdater` if we actually found locals to remove.
-    if map.iter().any(Option::is_none) {
-        // Update references to all vars and tmps now
-        let mut updater = LocalUpdater { map, tcx };
-        updater.visit_body_preserves_cfg(body);
-
-        body.local_decls.shrink_to_fit();
-    }
 }
 
 /// Construct the mapping while swapping out unused stuff out from the `vec`.