[mir-opt] Handle aggregates in SimplifyLocals pass

Author: wesleywiser

src/librustc_mir/transform/simplify.rs

@@ -359,13 +359,20 @@ impl<'a, 'tcx> Visitor<'tcx> for DeclMarker<'a, 'tcx> {
         // Ignore stores of constants because `ConstProp` and `CopyProp` can remove uses of many
         // of these locals. However, if the local is still needed, then it will be referenced in
         // another place and we'll mark it as being used there.
-        if ctx == PlaceContext::MutatingUse(MutatingUseContext::Store) {
-            let stmt =
-                &self.body.basic_blocks()[location.block].statements[location.statement_index];
-            if let StatementKind::Assign(box (p, Rvalue::Use(Operand::Constant(c)))) = &stmt.kind {
-                if p.as_local().is_some() {
-                    trace!("skipping store of const value {:?} to {:?}", c, local);
-                    return;
+        if ctx == PlaceContext::MutatingUse(MutatingUseContext::Store) ||
+           ctx == PlaceContext::MutatingUse(MutatingUseContext::Projection) {
+            let block = &self.body.basic_blocks()[location.block];
+            if location.statement_index != block.statements.len() {
+                let stmt =
+                    &block.statements[location.statement_index];
+
+                if let StatementKind::Assign(
+                    box (p, Rvalue::Use(Operand::Constant(c)))
+                ) = &stmt.kind {
+                    if !p.is_indirect() {
+                        trace!("skipping store of const value {:?} to {:?}", c, p);
+                        return;
+                    }
                 }
             }
         }
@@ -392,7 +399,7 @@ impl<'tcx> MutVisitor<'tcx> for LocalUpdater<'tcx> {
                     self.map[*l].is_some()
                 }
                 StatementKind::Assign(box (place, _)) => {
-                    if let Some(local) = place.as_local() {
+                    if let PlaceBase::Local(local) = place.base {
                         self.map[local].is_some()
                     } else {
                         true

src/test/incremental/hashes/struct_constructors.rs

@@ -152,7 +152,7 @@ pub fn change_constructor_path_regular_struct() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,optimized_mir,mir_built,typeck_tables_of")]
+#[rustc_clean(cfg="cfail2", except="HirBody,mir_built,typeck_tables_of")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_regular_struct() {
     let _ = RegularStruct2 {
@@ -213,7 +213,7 @@ pub fn change_constructor_path_tuple_struct() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,optimized_mir,mir_built,typeck_tables_of")]
+#[rustc_clean(cfg="cfail2", except="HirBody,mir_built,typeck_tables_of")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_tuple_struct() {
     let _ = TupleStruct2(0, 1, 2);

src/test/mir-opt/const_prop/return_place.rs

@@ -46,10 +46,7 @@ fn main() {
 // START rustc.add.PreCodegen.before.mir
 // fn add() -> u32 {
 //     let mut _0: u32;
-//     let mut _1: (u32, bool);
 //     bb0: {
-//         (_1.0: u32) = const 4u32;
-//         (_1.1: bool) = const false;
 //         _0 = const 4u32;
 //         return;
 //     }