Add de-init to destination place

11 files changed, 181 insertions, 120 deletions

diff --git a/compiler/rustc_mir_transform/src/large_enums.rs b/compiler/rustc_mir_transform/src/large_enums.rs
index 3f8662ad697..89f8de23583 100644
--- a/compiler/rustc_mir_transform/src/large_enums.rs
+++ b/compiler/rustc_mir_transform/src/large_enums.rs
@@ -4,6 +4,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::mir::interpret::AllocId;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, AdtDef, Const, ParamEnv, Ty, TyCtxt};
+use rustc_session::Session;
 use rustc_target::abi::{HasDataLayout, Size, TagEncoding, Variants};
 
 /// A pass that seeks to optimize unnecessary moves of large enum types, if there is a large
@@ -28,14 +29,12 @@ pub struct EnumSizeOpt {
 }
 
 impl<'tcx> MirPass<'tcx> for EnumSizeOpt {
+    fn is_enabled(&self, sess: &Session) -> bool {
+        sess.opts.unstable_opts.unsound_mir_opts || sess.mir_opt_level() >= 3
+    }
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        let sess = tcx.sess;
-        // FIXME(julianknodt): one thing noticed while testing this mir-opt is that there is a
-        // different layout of large enums on wasm. It's not clear what is causing this layout
-        // difference, as it should be identical to i686 (32 bit).
-        if (!sess.opts.unstable_opts.unsound_mir_opts) || sess.mir_opt_level() < 3 {
-            return;
-        }
+        // NOTE: This pass may produce different MIR based on the alignment of the target
+        // platform, but it will still be valid.
         self.optim(tcx, body);
     }
 }
@@ -254,6 +253,9 @@ impl EnumSizeOpt {
                         )),
                     };
 
+                    let deinit_old =
+                        Statement { source_info, kind: StatementKind::Deinit(box dst) };
+
                     let copy_bytes = Statement {
                         source_info,
                         kind: StatementKind::Intrinsic(
@@ -279,6 +281,7 @@ impl EnumSizeOpt {
                         dst_cast,
                         src_ptr,
                         src_cast,
+                        deinit_old,
                         copy_bytes,
                         store_dead,
                     ]
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index be3652dd3e7..45cd4024c9f 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -547,7 +547,6 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         tcx,
         body,
         &[
-            &large_enums::EnumSizeOpt { discrepancy: 128 },
             &reveal_all::RevealAll, // has to be done before inlining, since inlined code is in RevealAll mode.
             &lower_slice_len::LowerSliceLenCalls, // has to be done before inlining, otherwise actual call will be almost always inlined. Also simple, so can just do first
             &unreachable_prop::UnreachablePropagation,
@@ -586,6 +585,7 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &simplify::SimplifyLocals::new("final"),
             &multiple_return_terminators::MultipleReturnTerminators,
             &deduplicate_blocks::DeduplicateBlocks,
+            &large_enums::EnumSizeOpt { discrepancy: 128 },
             // Some cleanup necessary at least for LLVM and potentially other codegen backends.
             &add_call_guards::CriticalCallEdges,
             // Dump the end result for testing and debugging purposes.
diff --git a/tests/mir-opt/enum_opt.cand.EnumSizeOpt.32bit.diff b/tests/mir-opt/enum_opt.cand.EnumSizeOpt.32bit.diff
index e0ba46c15f4..b139deeee1f 100644
--- a/tests/mir-opt/enum_opt.cand.EnumSizeOpt.32bit.diff
+++ b/tests/mir-opt/enum_opt.cand.EnumSizeOpt.32bit.diff
@@ -1,11 +1,11 @@
 - // MIR for `cand` before EnumSizeOpt
 + // MIR for `cand` after EnumSizeOpt
   
-  fn cand() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:15: +0:15
+  fn cand() -> Candidate {
+      let mut _0: Candidate;               // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:27
       let mut _1: Candidate;               // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: Candidate;               // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:34
-      let mut _3: [u64; 1024];             // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
+      let mut _3: [u8; 8196];              // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
 +     let mut _4: [usize; 2];              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _5: isize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _6: usize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
@@ -14,25 +14,29 @@
 +     let mut _9: *mut u8;                 // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _10: *const Candidate;       // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _11: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
++     let mut _12: [usize; 2];             // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _13: isize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _14: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _15: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _16: *mut Candidate;         // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _17: *mut u8;                // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _18: *const Candidate;       // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _19: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
       scope 1 {
           debug a => _1;                   // in scope 1 at $DIR/enum_opt.rs:+1:7: +1:12
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
-          ((_1 as Small).0: u8) = const 1_u8; // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
+          _1 = Candidate::Small(const 1_u8); // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          _3 = [const 1_u64; 1024];        // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          ((_2 as Large).0: [u64; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
+          _3 = [const 1_u8; 8196];         // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
+          _2 = Candidate::Large(move _3);  // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
 -         _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
-+         _4 = const [2_usize, 8196_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
++         _4 = const [2_usize, 8197_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _5 = discriminant(_2);           // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _6 = _5 as usize (IntToInt);     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _7 = _4[_6];                     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
@@ -40,12 +44,25 @@
 +         _9 = _8 as *mut u8 (PtrToPtr);   // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _10 = &raw const _2;             // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _11 = _10 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
++         Deinit(_8);                      // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         copy_nonoverlapping(dst = _9, src = _11, count = _7); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:15: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+-         _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageLive(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _12 = const [2_usize, 8197_usize]; // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _13 = discriminant(_1);          // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _14 = _13 as usize (IntToInt);   // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _15 = _12[_14];                  // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _16 = &raw mut _0;               // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _17 = _16 as *mut u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _18 = &raw const _1;             // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _19 = _18 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         Deinit(_16);                     // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         copy_nonoverlapping(dst = _17, src = _19, count = _15); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageDead(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.cand.EnumSizeOpt.64bit.diff b/tests/mir-opt/enum_opt.cand.EnumSizeOpt.64bit.diff
index 67439dba9c9..b139deeee1f 100644
--- a/tests/mir-opt/enum_opt.cand.EnumSizeOpt.64bit.diff
+++ b/tests/mir-opt/enum_opt.cand.EnumSizeOpt.64bit.diff
@@ -1,11 +1,11 @@
 - // MIR for `cand` before EnumSizeOpt
 + // MIR for `cand` after EnumSizeOpt
   
-  fn cand() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:15: +0:15
+  fn cand() -> Candidate {
+      let mut _0: Candidate;               // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:27
       let mut _1: Candidate;               // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: Candidate;               // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:34
-      let mut _3: [u64; 1024];             // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
+      let mut _3: [u8; 8196];              // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
 +     let mut _4: [usize; 2];              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _5: isize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _6: usize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
@@ -14,25 +14,29 @@
 +     let mut _9: *mut u8;                 // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _10: *const Candidate;       // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
 +     let mut _11: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:34
++     let mut _12: [usize; 2];             // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _13: isize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _14: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _15: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _16: *mut Candidate;         // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _17: *mut u8;                // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _18: *const Candidate;       // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _19: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
       scope 1 {
           debug a => _1;                   // in scope 1 at $DIR/enum_opt.rs:+1:7: +1:12
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
-          ((_1 as Small).0: u8) = const 1_u8; // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
+          _1 = Candidate::Small(const 1_u8); // scope 0 at $DIR/enum_opt.rs:+1:15: +1:34
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          _3 = [const 1_u64; 1024];        // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          ((_2 as Large).0: [u64; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
+          _3 = [const 1_u8; 8196];         // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
+          _2 = Candidate::Large(move _3);  // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
 -         _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
-+         _4 = const [2_usize, 8200_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
++         _4 = const [2_usize, 8197_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _5 = discriminant(_2);           // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _6 = _5 as usize (IntToInt);     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _7 = _4[_6];                     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
@@ -40,12 +44,25 @@
 +         _9 = _8 as *mut u8 (PtrToPtr);   // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _10 = &raw const _2;             // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         _11 = _10 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
++         Deinit(_8);                      // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         copy_nonoverlapping(dst = _9, src = _11, count = _7); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
 +         StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:15: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+-         _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageLive(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _12 = const [2_usize, 8197_usize]; // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _13 = discriminant(_1);          // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _14 = _13 as usize (IntToInt);   // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _15 = _12[_14];                  // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _16 = &raw mut _0;               // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _17 = _16 as *mut u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _18 = &raw const _1;             // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _19 = _18 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         Deinit(_16);                     // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         copy_nonoverlapping(dst = _17, src = _19, count = _15); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageDead(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.32bit.diff b/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.32bit.diff
index db2efa195a3..a80001149eb 100644
--- a/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.32bit.diff
+++ b/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.32bit.diff
@@ -1,8 +1,8 @@
 - // MIR for `invalid` before EnumSizeOpt
 + // MIR for `invalid` after EnumSizeOpt
   
-  fn invalid() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:18
+  fn invalid() -> InvalidIdxs {
+      let mut _0: InvalidIdxs;             // return place in scope 0 at $DIR/enum_opt.rs:+0:21: +0:32
       let mut _1: InvalidIdxs;             // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: InvalidIdxs;             // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:36
       let mut _3: [u64; 1024];             // in scope 0 at $DIR/enum_opt.rs:+2:26: +2:35
@@ -12,20 +12,17 @@
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
+          _1 = InvalidIdxs::A;             // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:26: +2:35
           _3 = [const 0_u64; 1024];        // scope 1 at $DIR/enum_opt.rs:+2:26: +2:35
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
-          ((_2 as Large).0: [u64; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
+          _2 = InvalidIdxs::Large(move _3); // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:35: +2:36
           _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:36
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:35: +2:36
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:18: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+          _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.64bit.diff b/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.64bit.diff
index db2efa195a3..a80001149eb 100644
--- a/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.64bit.diff
+++ b/tests/mir-opt/enum_opt.invalid.EnumSizeOpt.64bit.diff
@@ -1,8 +1,8 @@
 - // MIR for `invalid` before EnumSizeOpt
 + // MIR for `invalid` after EnumSizeOpt
   
-  fn invalid() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:18
+  fn invalid() -> InvalidIdxs {
+      let mut _0: InvalidIdxs;             // return place in scope 0 at $DIR/enum_opt.rs:+0:21: +0:32
       let mut _1: InvalidIdxs;             // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: InvalidIdxs;             // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:36
       let mut _3: [u64; 1024];             // in scope 0 at $DIR/enum_opt.rs:+2:26: +2:35
@@ -12,20 +12,17 @@
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
+          _1 = InvalidIdxs::A;             // scope 0 at $DIR/enum_opt.rs:+1:15: +1:29
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:26: +2:35
           _3 = [const 0_u64; 1024];        // scope 1 at $DIR/enum_opt.rs:+2:26: +2:35
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
-          ((_2 as Large).0: [u64; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
+          _2 = InvalidIdxs::Large(move _3); // scope 1 at $DIR/enum_opt.rs:+2:7: +2:36
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:35: +2:36
           _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:36
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:35: +2:36
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:18: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+          _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.rs b/tests/mir-opt/enum_opt.rs
index 6876c56cfa4..2768d708049 100644
--- a/tests/mir-opt/enum_opt.rs
+++ b/tests/mir-opt/enum_opt.rs
@@ -1,20 +1,19 @@
+// unit-test: EnumSizeOpt
 // EMIT_MIR_FOR_EACH_BIT_WIDTH
-// compile-flags: -Zunsound-mir-opts -Zmir-opt-level=3
-// ignore-wasm32
+// compile-flags: -Zunsound-mir-opts
 
 #![feature(arbitrary_enum_discriminant, repr128)]
 
 // Tests that an enum with a variant with no data gets correctly transformed.
-#[repr(C)]
 pub enum NoData {
-  Large([u8; 8192]),
+  Large([u8; 8196]),
   None,
 }
 
 // Tests that an enum with a variant with data that is a valid candidate gets transformed.
 pub enum Candidate {
   Small(u8),
-  Large([u64; 1024]),
+  Large([u8; 8196]),
 }
 
 // Tests that an enum which has a discriminant much higher than the variant does not get
@@ -43,34 +42,39 @@ pub enum RandOrderDiscr {
 }
 
 // EMIT_MIR enum_opt.unin.EnumSizeOpt.diff
-pub fn unin() {
+pub fn unin() -> NoData {
   let mut a = NoData::None;
-  a = NoData::Large([1; 8192]);
+  a = NoData::Large([1; 8196]);
+  a
 }
 
 // EMIT_MIR enum_opt.cand.EnumSizeOpt.diff
-pub fn cand() {
+pub fn cand() -> Candidate {
   let mut a = Candidate::Small(1);
-  a = Candidate::Large([1; 1024]);
+  a = Candidate::Large([1; 8196]);
+  a
 }
 
 // EMIT_MIR enum_opt.invalid.EnumSizeOpt.diff
-pub fn invalid() {
+pub fn invalid() -> InvalidIdxs {
   let mut a = InvalidIdxs::A;
   a = InvalidIdxs::Large([0; 1024]);
+  a
 }
 
 // EMIT_MIR enum_opt.trunc.EnumSizeOpt.diff
-pub fn trunc() {
+pub fn trunc() -> NotTrunctable {
   let mut a = NotTrunctable::A;
   a = NotTrunctable::B([0; 1024]);
   a = NotTrunctable::C([0; 4096]);
+  a
 }
 
-pub fn rand_order() {
+pub fn rand_order() -> RandOrderDiscr {
   let mut a = RandOrderDiscr::A;
   a = RandOrderDiscr::B([0; 1024]);
   a = RandOrderDiscr::C;
+  a
 }
 
 pub fn main() {
diff --git a/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.32bit.diff b/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.32bit.diff
index b9d6765d8c1..1ef79044d4f 100644
--- a/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.32bit.diff
+++ b/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.32bit.diff
@@ -1,8 +1,8 @@
 - // MIR for `trunc` before EnumSizeOpt
 + // MIR for `trunc` after EnumSizeOpt
   
-  fn trunc() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:16: +0:16
+  fn trunc() -> NotTrunctable {
+      let mut _0: NotTrunctable;           // return place in scope 0 at $DIR/enum_opt.rs:+0:19: +0:32
       let mut _1: NotTrunctable;           // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: NotTrunctable;           // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:34
       let mut _3: [u8; 1024];              // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
@@ -14,29 +14,24 @@
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
+          _1 = NotTrunctable::A;           // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
           _3 = [const 0_u8; 1024];         // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          ((_2 as B).0: [u8; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
+          _2 = NotTrunctable::B(move _3);  // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
           _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
           StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
           StorageLive(_5);                 // scope 1 at $DIR/enum_opt.rs:+3:24: +3:33
           _5 = [const 0_u8; 4096];         // scope 1 at $DIR/enum_opt.rs:+3:24: +3:33
-          Deinit(_4);                      // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
-          ((_4 as C).0: [u8; 4096]) = move _5; // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
-          discriminant(_4) = 2;            // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
+          _4 = NotTrunctable::C(move _5);  // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
           StorageDead(_5);                 // scope 1 at $DIR/enum_opt.rs:+3:33: +3:34
           _1 = move _4;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:34
           StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+3:33: +3:34
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:16: +4:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
+          _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+4:3: +4:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+5:1: +5:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+5:2: +5:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.64bit.diff b/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.64bit.diff
index b9d6765d8c1..1ef79044d4f 100644
--- a/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.64bit.diff
+++ b/tests/mir-opt/enum_opt.trunc.EnumSizeOpt.64bit.diff
@@ -1,8 +1,8 @@
 - // MIR for `trunc` before EnumSizeOpt
 + // MIR for `trunc` after EnumSizeOpt
   
-  fn trunc() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:16: +0:16
+  fn trunc() -> NotTrunctable {
+      let mut _0: NotTrunctable;           // return place in scope 0 at $DIR/enum_opt.rs:+0:19: +0:32
       let mut _1: NotTrunctable;           // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: NotTrunctable;           // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:34
       let mut _3: [u8; 1024];              // in scope 0 at $DIR/enum_opt.rs:+2:24: +2:33
@@ -14,29 +14,24 @@
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
-          discriminant(_1) = 0;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
+          _1 = NotTrunctable::A;           // scope 0 at $DIR/enum_opt.rs:+1:15: +1:31
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
           _3 = [const 0_u8; 1024];         // scope 1 at $DIR/enum_opt.rs:+2:24: +2:33
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          ((_2 as B).0: [u8; 1024]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
-          discriminant(_2) = 1;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
+          _2 = NotTrunctable::B(move _3);  // scope 1 at $DIR/enum_opt.rs:+2:7: +2:34
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
           _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:34
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:33: +2:34
           StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
           StorageLive(_5);                 // scope 1 at $DIR/enum_opt.rs:+3:24: +3:33
           _5 = [const 0_u8; 4096];         // scope 1 at $DIR/enum_opt.rs:+3:24: +3:33
-          Deinit(_4);                      // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
-          ((_4 as C).0: [u8; 4096]) = move _5; // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
-          discriminant(_4) = 2;            // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
+          _4 = NotTrunctable::C(move _5);  // scope 1 at $DIR/enum_opt.rs:+3:7: +3:34
           StorageDead(_5);                 // scope 1 at $DIR/enum_opt.rs:+3:33: +3:34
           _1 = move _4;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:34
           StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+3:33: +3:34
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:16: +4:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
+          _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+4:3: +4:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+5:1: +5:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+5:2: +5:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
index 168677b173d..ad9f12cf959 100644
--- a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
+++ b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.32bit.diff
@@ -1,11 +1,11 @@
 - // MIR for `unin` before EnumSizeOpt
 + // MIR for `unin` after EnumSizeOpt
   
-  fn unin() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:15: +0:15
+  fn unin() -> NoData {
+      let mut _0: NoData;                  // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:24
       let mut _1: NoData;                  // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: NoData;                  // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:31
-      let mut _3: [u8; 8192];              // in scope 0 at $DIR/enum_opt.rs:+2:21: +2:30
+      let mut _3: [u8; 8196];              // in scope 0 at $DIR/enum_opt.rs:+2:21: +2:30
 +     let mut _4: [usize; 2];              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _5: isize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _6: usize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
@@ -14,24 +14,29 @@
 +     let mut _9: *mut u8;                 // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _10: *const NoData;          // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _11: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
++     let mut _12: [usize; 2];             // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _13: isize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _14: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _15: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _16: *mut NoData;            // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _17: *mut u8;                // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _18: *const NoData;          // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _19: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
       scope 1 {
           debug a => _1;                   // in scope 1 at $DIR/enum_opt.rs:+1:7: +1:12
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
-          discriminant(_1) = 1;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
+          _1 = NoData::None;               // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
-          _3 = [const 1_u8; 8192];         // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
-          ((_2 as Large).0: [u8; 8192]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
-          discriminant(_2) = 0;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
+          _3 = [const 1_u8; 8196];         // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
+          _2 = NoData::Large(move _3);     // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:30: +2:31
 -         _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
-+         _4 = const [8196_usize, 4_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
++         _4 = const [8197_usize, 1_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _5 = discriminant(_2);           // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _6 = _5 as usize (IntToInt);     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _7 = _4[_6];                     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
@@ -39,12 +44,25 @@
 +         _9 = _8 as *mut u8 (PtrToPtr);   // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _10 = &raw const _2;             // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _11 = _10 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
++         Deinit(_8);                      // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         copy_nonoverlapping(dst = _9, src = _11, count = _7); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:30: +2:31
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:15: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+-         _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageLive(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _12 = const [8197_usize, 1_usize]; // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _13 = discriminant(_1);          // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _14 = _13 as usize (IntToInt);   // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _15 = _12[_14];                  // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _16 = &raw mut _0;               // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _17 = _16 as *mut u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _18 = &raw const _1;             // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _19 = _18 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         Deinit(_16);                     // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         copy_nonoverlapping(dst = _17, src = _19, count = _15); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageDead(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }
   
diff --git a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.64bit.diff b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.64bit.diff
index 168677b173d..ad9f12cf959 100644
--- a/tests/mir-opt/enum_opt.unin.EnumSizeOpt.64bit.diff
+++ b/tests/mir-opt/enum_opt.unin.EnumSizeOpt.64bit.diff
@@ -1,11 +1,11 @@
 - // MIR for `unin` before EnumSizeOpt
 + // MIR for `unin` after EnumSizeOpt
   
-  fn unin() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/enum_opt.rs:+0:15: +0:15
+  fn unin() -> NoData {
+      let mut _0: NoData;                  // return place in scope 0 at $DIR/enum_opt.rs:+0:18: +0:24
       let mut _1: NoData;                  // in scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
       let mut _2: NoData;                  // in scope 0 at $DIR/enum_opt.rs:+2:7: +2:31
-      let mut _3: [u8; 8192];              // in scope 0 at $DIR/enum_opt.rs:+2:21: +2:30
+      let mut _3: [u8; 8196];              // in scope 0 at $DIR/enum_opt.rs:+2:21: +2:30
 +     let mut _4: [usize; 2];              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _5: isize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _6: usize;                   // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
@@ -14,24 +14,29 @@
 +     let mut _9: *mut u8;                 // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _10: *const NoData;          // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
 +     let mut _11: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+2:3: +2:31
++     let mut _12: [usize; 2];             // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _13: isize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _14: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _15: usize;                  // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _16: *mut NoData;            // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _17: *mut u8;                // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _18: *const NoData;          // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
++     let mut _19: *const u8;              // in scope 0 at $DIR/enum_opt.rs:+3:3: +3:4
       scope 1 {
           debug a => _1;                   // in scope 1 at $DIR/enum_opt.rs:+1:7: +1:12
       }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/enum_opt.rs:+1:7: +1:12
-          Deinit(_1);                      // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
-          discriminant(_1) = 1;            // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
+          _1 = NoData::None;               // scope 0 at $DIR/enum_opt.rs:+1:15: +1:27
           StorageLive(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
           StorageLive(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
-          _3 = [const 1_u8; 8192];         // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
-          Deinit(_2);                      // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
-          ((_2 as Large).0: [u8; 8192]) = move _3; // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
-          discriminant(_2) = 0;            // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
+          _3 = [const 1_u8; 8196];         // scope 1 at $DIR/enum_opt.rs:+2:21: +2:30
+          _2 = NoData::Large(move _3);     // scope 1 at $DIR/enum_opt.rs:+2:7: +2:31
           StorageDead(_3);                 // scope 1 at $DIR/enum_opt.rs:+2:30: +2:31
 -         _1 = move _2;                    // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         StorageLive(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
-+         _4 = const [8196_usize, 4_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
++         _4 = const [8197_usize, 1_usize]; // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _5 = discriminant(_2);           // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _6 = _5 as usize (IntToInt);     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _7 = _4[_6];                     // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
@@ -39,12 +44,25 @@
 +         _9 = _8 as *mut u8 (PtrToPtr);   // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _10 = &raw const _2;             // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         _11 = _10 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
++         Deinit(_8);                      // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         copy_nonoverlapping(dst = _9, src = _11, count = _7); // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
 +         StorageDead(_4);                 // scope 1 at $DIR/enum_opt.rs:+2:3: +2:31
           StorageDead(_2);                 // scope 1 at $DIR/enum_opt.rs:+2:30: +2:31
-          _0 = const ();                   // scope 0 at $DIR/enum_opt.rs:+0:15: +3:2
-          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+3:1: +3:2
-          return;                          // scope 0 at $DIR/enum_opt.rs:+3:2: +3:2
+-         _0 = move _1;                    // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageLive(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _12 = const [8197_usize, 1_usize]; // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _13 = discriminant(_1);          // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _14 = _13 as usize (IntToInt);   // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _15 = _12[_14];                  // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _16 = &raw mut _0;               // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _17 = _16 as *mut u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _18 = &raw const _1;             // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         _19 = _18 as *const u8 (PtrToPtr); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         Deinit(_16);                     // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         copy_nonoverlapping(dst = _17, src = _19, count = _15); // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
++         StorageDead(_12);                // scope 1 at $DIR/enum_opt.rs:+3:3: +3:4
+          StorageDead(_1);                 // scope 0 at $DIR/enum_opt.rs:+4:1: +4:2
+          return;                          // scope 0 at $DIR/enum_opt.rs:+4:2: +4:2
       }
   }