Merging upstream version 1.67.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 237 insertions, 77 deletions

diff --git a/src/test/mir-opt/dest-prop/branch.main.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/branch.foo.DestinationPropagation.diff
index 8929f2cc7..5fa7013d5 100644
--- a/src/test/mir-opt/dest-prop/branch.main.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/branch.foo.DestinationPropagation.diff
@@ -1,29 +1,34 @@
-- // MIR for `main` before DestinationPropagation
-+ // MIR for `main` after DestinationPropagation
+- // MIR for `foo` before DestinationPropagation
++ // MIR for `foo` after DestinationPropagation
   
-  fn main() -> () {
-      let mut _0: ();                      // return place in scope 0 at $DIR/branch.rs:+0:11: +0:11
+  fn foo() -> i32 {
+      let mut _0: i32;                     // return place in scope 0 at $DIR/branch.rs:+0:13: +0:16
       let _1: i32;                         // in scope 0 at $DIR/branch.rs:+1:9: +1:10
       let mut _3: bool;                    // in scope 0 at $DIR/branch.rs:+3:16: +3:22
       let _4: i32;                         // in scope 0 at $DIR/branch.rs:+6:9: +6:14
       scope 1 {
-          debug x => _1;                   // in scope 1 at $DIR/branch.rs:+1:9: +1:10
+-         debug x => _1;                   // in scope 1 at $DIR/branch.rs:+1:9: +1:10
++         debug x => _0;                   // in scope 1 at $DIR/branch.rs:+1:9: +1:10
           let _2: i32;                     // in scope 1 at $DIR/branch.rs:+3:9: +3:10
           scope 2 {
-              debug y => _2;               // in scope 2 at $DIR/branch.rs:+3:9: +3:10
+-             debug y => _2;               // in scope 2 at $DIR/branch.rs:+3:9: +3:10
++             debug y => _0;               // in scope 2 at $DIR/branch.rs:+3:9: +3:10
           }
       }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/branch.rs:+1:9: +1:10
-          _1 = val() -> bb1;               // scope 0 at $DIR/branch.rs:+1:13: +1:18
+-         StorageLive(_1);                 // scope 0 at $DIR/branch.rs:+1:9: +1:10
+-         _1 = val() -> bb1;               // scope 0 at $DIR/branch.rs:+1:13: +1:18
++         nop;                             // scope 0 at $DIR/branch.rs:+1:9: +1:10
++         _0 = val() -> bb1;               // scope 0 at $DIR/branch.rs:+1:13: +1:18
                                            // mir::Constant
                                            // + span: $DIR/branch.rs:13:13: 13:16
                                            // + literal: Const { ty: fn() -> i32 {val}, val: Value(<ZST>) }
       }
   
       bb1: {
-          StorageLive(_2);                 // scope 1 at $DIR/branch.rs:+3:9: +3:10
+-         StorageLive(_2);                 // scope 1 at $DIR/branch.rs:+3:9: +3:10
++         nop;                             // scope 1 at $DIR/branch.rs:+3:9: +3:10
           StorageLive(_3);                 // scope 1 at $DIR/branch.rs:+3:16: +3:22
           _3 = cond() -> bb2;              // scope 1 at $DIR/branch.rs:+3:16: +3:22
                                            // mir::Constant
@@ -36,7 +41,8 @@
       }
   
       bb3: {
-          nop;                             // scope 1 at $DIR/branch.rs:+4:9: +4:10
+-         _2 = _1;                         // scope 1 at $DIR/branch.rs:+4:9: +4:10
++         nop;                             // scope 1 at $DIR/branch.rs:+4:9: +4:10
           goto -> bb6;                     // scope 1 at $DIR/branch.rs:+3:13: +8:6
       }
   
@@ -50,16 +56,20 @@
   
       bb5: {
           StorageDead(_4);                 // scope 1 at $DIR/branch.rs:+6:14: +6:15
-          nop;                             // scope 1 at $DIR/branch.rs:+7:9: +7:10
+-         _2 = _1;                         // scope 1 at $DIR/branch.rs:+7:9: +7:10
++         nop;                             // scope 1 at $DIR/branch.rs:+7:9: +7:10
           goto -> bb6;                     // scope 1 at $DIR/branch.rs:+3:13: +8:6
       }
   
       bb6: {
           StorageDead(_3);                 // scope 1 at $DIR/branch.rs:+8:5: +8:6
-          nop;                             // scope 0 at $DIR/branch.rs:+0:11: +9:2
-          StorageDead(_2);                 // scope 1 at $DIR/branch.rs:+9:1: +9:2
-          StorageDead(_1);                 // scope 0 at $DIR/branch.rs:+9:1: +9:2
-          return;                          // scope 0 at $DIR/branch.rs:+9:2: +9:2
+-         _0 = _2;                         // scope 2 at $DIR/branch.rs:+10:5: +10:6
+-         StorageDead(_2);                 // scope 1 at $DIR/branch.rs:+11:1: +11:2
+-         StorageDead(_1);                 // scope 0 at $DIR/branch.rs:+11:1: +11:2
++         nop;                             // scope 2 at $DIR/branch.rs:+10:5: +10:6
++         nop;                             // scope 1 at $DIR/branch.rs:+11:1: +11:2
++         nop;                             // scope 0 at $DIR/branch.rs:+11:1: +11:2
+          return;                          // scope 0 at $DIR/branch.rs:+11:2: +11:2
       }
   }
   
diff --git a/src/test/mir-opt/dest-prop/branch.rs b/src/test/mir-opt/dest-prop/branch.rs
index fffcf82b3..898c908b1 100644
--- a/src/test/mir-opt/dest-prop/branch.rs
+++ b/src/test/mir-opt/dest-prop/branch.rs
@@ -1,5 +1,5 @@
 //! Tests that assignment in both branches of an `if` are eliminated.
-// compile-flags: -Zunsound-mir-opts
+// unit-test: DestinationPropagation
 fn val() -> i32 {
     1
 }
@@ -8,8 +8,8 @@ fn cond() -> bool {
     true
 }
 
-// EMIT_MIR branch.main.DestinationPropagation.diff
-fn main() {
+// EMIT_MIR branch.foo.DestinationPropagation.diff
+fn foo() -> i32 {
     let x = val();
 
     let y = if cond() {
@@ -18,4 +18,10 @@ fn main() {
         val();
         x
     };
+
+    y
+}
+
+fn main() {
+    foo();
 }
diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.arg_src.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/copy_propagation_arg.arg_src.DestinationPropagation.diff
index f28bc72df..4343a5935 100644
--- a/src/test/mir-opt/dest-prop/copy_propagation_arg.arg_src.DestinationPropagation.diff
+++ b/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 => const 123_i32;            // in scope 0 at $DIR/copy_propagation_arg.rs:+0:12: +0:17
+      debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:+0:12: +0:17
       let mut _0: i32;                     // return place in scope 0 at $DIR/copy_propagation_arg.rs:+0:27: +0:30
       let _2: i32;                         // in scope 0 at $DIR/copy_propagation_arg.rs:+1:9: +1:10
       scope 1 {
@@ -15,7 +15,7 @@
 -         _2 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+1:13: +1:14
 +         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+1:9: +1:10
 +         _0 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+1:13: +1:14
-          nop;                             // scope 1 at $DIR/copy_propagation_arg.rs:+2:5: +2:12
+          _1 = const 123_i32;              // scope 1 at $DIR/copy_propagation_arg.rs:+2:5: +2:12
 -         _0 = _2;                         // scope 1 at $DIR/copy_propagation_arg.rs:+3:5: +3:6
 -         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+4:1: +4:2
 +         nop;                             // scope 1 at $DIR/copy_propagation_arg.rs:+3:5: +3:6
diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.bar.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/copy_propagation_arg.bar.DestinationPropagation.diff
index a8a7e9ab6..298991b5a 100644
--- a/src/test/mir-opt/dest-prop/copy_propagation_arg.bar.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/copy_propagation_arg.bar.DestinationPropagation.diff
@@ -2,26 +2,30 @@
 + // MIR for `bar` after DestinationPropagation
   
   fn bar(_1: u8) -> () {
-      debug x => const 5_u8;               // in scope 0 at $DIR/copy_propagation_arg.rs:+0:8: +0:13
+      debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:+0:8: +0:13
       let mut _0: ();                      // return place in scope 0 at $DIR/copy_propagation_arg.rs:+0:19: +0:19
       let _2: u8;                          // in scope 0 at $DIR/copy_propagation_arg.rs:+1:5: +1:13
       let mut _3: u8;                      // in scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
   
       bb0: {
           StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:5: +1:13
-          StorageLive(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
-          _3 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
-          _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+1:5: +1:13
+-         StorageLive(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
+-         _3 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
+-         _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+1:5: +1:13
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+1:11: +1:12
++         _2 = dummy(move _1) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+1:5: +1:13
                                            // mir::Constant
                                            // + span: $DIR/copy_propagation_arg.rs:16:5: 16:10
                                            // + literal: Const { ty: fn(u8) -> u8 {dummy}, val: Value(<ZST>) }
       }
   
       bb1: {
-          StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:12: +1:13
+-         StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:12: +1:13
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+1:12: +1:13
           StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:13: +1:14
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:10
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+0:19: +3:2
+          _1 = const 5_u8;                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:10
+          _0 = const ();                   // scope 0 at $DIR/copy_propagation_arg.rs:+0:19: +3:2
           return;                          // scope 0 at $DIR/copy_propagation_arg.rs:+3:2: +3:2
       }
   }
diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.baz.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/copy_propagation_arg.baz.DestinationPropagation.diff
index ce9be4c27..bc88787e6 100644
--- a/src/test/mir-opt/dest-prop/copy_propagation_arg.baz.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/copy_propagation_arg.baz.DestinationPropagation.diff
@@ -1,18 +1,22 @@
 - // MIR for `baz` before DestinationPropagation
 + // MIR for `baz` after DestinationPropagation
   
-  fn baz(_1: i32) -> () {
+  fn baz(_1: i32) -> i32 {
       debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:+0:8: +0:13
-      let mut _0: ();                      // return place in scope 0 at $DIR/copy_propagation_arg.rs:+0:20: +0:20
+      let mut _0: i32;                     // return place in scope 0 at $DIR/copy_propagation_arg.rs:+0:23: +0:26
       let mut _2: i32;                     // in scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
   
       bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:10
-          StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+0:20: +3:2
-          return;                          // scope 0 at $DIR/copy_propagation_arg.rs:+3:2: +3:2
+-         StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
+-         _2 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
+-         _1 = move _2;                    // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:10
+-         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:10
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:10
+          _0 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+3:5: +3:6
+          return;                          // scope 0 at $DIR/copy_propagation_arg.rs:+4:2: +4:2
       }
   }
   
diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.diff
index d7a0b950f..d37a9f71d 100644
--- a/src/test/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.diff
@@ -8,10 +8,12 @@
       let mut _3: u8;                      // in scope 0 at $DIR/copy_propagation_arg.rs:+2:15: +2:16
   
       bb0: {
-          StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
+-         StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
           StorageLive(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:15: +2:16
           _3 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+2:15: +2:16
-          _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
+-         _2 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
++         _1 = dummy(move _3) -> bb1;      // scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
                                            // mir::Constant
                                            // + span: $DIR/copy_propagation_arg.rs:11:9: 11:14
                                            // + literal: Const { ty: fn(u8) -> u8 {dummy}, val: Value(<ZST>) }
@@ -19,9 +21,11 @@
   
       bb1: {
           StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:16: +2:17
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:17
-          StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:16: +2:17
-          nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+0:19: +3:2
+-         _1 = move _2;                    // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:17
+-         StorageDead(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:16: +2:17
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:5: +2:17
++         nop;                             // scope 0 at $DIR/copy_propagation_arg.rs:+2:16: +2:17
+          _0 = const ();                   // scope 0 at $DIR/copy_propagation_arg.rs:+0:19: +3:2
           return;                          // scope 0 at $DIR/copy_propagation_arg.rs:+3:2: +3:2
       }
   }
diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.rs b/src/test/mir-opt/dest-prop/copy_propagation_arg.rs
index a5fb0f640..31be6c931 100644
--- a/src/test/mir-opt/dest-prop/copy_propagation_arg.rs
+++ b/src/test/mir-opt/dest-prop/copy_propagation_arg.rs
@@ -1,6 +1,6 @@
 // Check that DestinationPropagation does not propagate an assignment to a function argument
 // (doing so can break usages of the original argument value)
-// compile-flags: -Zunsound-mir-opts
+// unit-test: DestinationPropagation
 fn dummy(x: u8) -> u8 {
     x
 }
@@ -18,9 +18,10 @@ fn bar(mut x: u8) {
 }
 
 // EMIT_MIR copy_propagation_arg.baz.DestinationPropagation.diff
-fn baz(mut x: i32) {
+fn baz(mut x: i32) -> i32 {
     // self-assignment to a function argument should be eliminated
     x = x;
+    x
 }
 
 // EMIT_MIR copy_propagation_arg.arg_src.DestinationPropagation.diff
diff --git a/src/test/mir-opt/dest-prop/cycle.main.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/cycle.main.DestinationPropagation.diff
index 8eeb0d354..cfc203c5f 100644
--- a/src/test/mir-opt/dest-prop/cycle.main.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/cycle.main.DestinationPropagation.diff
@@ -8,45 +8,69 @@
       let _5: ();                          // in scope 0 at $DIR/cycle.rs:+6:5: +6:12
       let mut _6: i32;                     // in scope 0 at $DIR/cycle.rs:+6:10: +6:11
       scope 1 {
-          debug x => _1;                   // in scope 1 at $DIR/cycle.rs:+1:9: +1:14
+-         debug x => _1;                   // in scope 1 at $DIR/cycle.rs:+1:9: +1:14
++         debug x => _6;                   // in scope 1 at $DIR/cycle.rs:+1:9: +1:14
           let _2: i32;                     // in scope 1 at $DIR/cycle.rs:+2:9: +2:10
           scope 2 {
-              debug y => _2;               // in scope 2 at $DIR/cycle.rs:+2:9: +2:10
+-             debug y => _2;               // in scope 2 at $DIR/cycle.rs:+2:9: +2:10
++             debug y => _6;               // in scope 2 at $DIR/cycle.rs:+2:9: +2:10
               let _3: i32;                 // in scope 2 at $DIR/cycle.rs:+3:9: +3:10
               scope 3 {
-                  debug z => _3;           // in scope 3 at $DIR/cycle.rs:+3:9: +3:10
-                  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
-                  }
+-                 debug z => _3;           // in scope 3 at $DIR/cycle.rs:+3:9: +3:10
++                 debug z => _6;           // in scope 3 at $DIR/cycle.rs:+3:9: +3:10
               }
           }
       }
   
       bb0: {
-          StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:+1:9: +1:14
-          _1 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:+1:17: +1:22
+-         StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:+1:9: +1:14
+-         _1 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:+1:17: +1:22
++         nop;                             // scope 0 at $DIR/cycle.rs:+1:9: +1:14
++         _6 = val() -> bb1;               // scope 0 at $DIR/cycle.rs:+1:17: +1:22
                                            // mir::Constant
                                            // + span: $DIR/cycle.rs:9:17: 9:20
                                            // + literal: Const { ty: fn() -> i32 {val}, val: Value(<ZST>) }
       }
   
       bb1: {
-          StorageLive(_2);                 // scope 1 at $DIR/cycle.rs:+2:9: +2:10
-          nop;                             // scope 1 at $DIR/cycle.rs:+2:13: +2:14
-          StorageLive(_3);                 // scope 2 at $DIR/cycle.rs:+3:9: +3:10
-          nop;                             // scope 2 at $DIR/cycle.rs:+3:13: +3:14
-          StorageLive(_4);                 // scope 3 at $DIR/cycle.rs:+4:9: +4:10
-          nop;                             // scope 3 at $DIR/cycle.rs:+4:9: +4:10
-          nop;                             // scope 3 at $DIR/cycle.rs:+4:5: +4:10
-          StorageDead(_4);                 // scope 3 at $DIR/cycle.rs:+4:9: +4:10
+-         StorageLive(_2);                 // scope 1 at $DIR/cycle.rs:+2:9: +2:10
+-         _2 = _1;                         // scope 1 at $DIR/cycle.rs:+2:13: +2:14
+-         StorageLive(_3);                 // scope 2 at $DIR/cycle.rs:+3:9: +3:10
+-         _3 = _2;                         // scope 2 at $DIR/cycle.rs:+3:13: +3:14
+-         StorageLive(_4);                 // scope 3 at $DIR/cycle.rs:+4:9: +4:10
+-         _4 = _3;                         // scope 3 at $DIR/cycle.rs:+4:9: +4:10
+-         _1 = move _4;                    // scope 3 at $DIR/cycle.rs:+4:5: +4:10
+-         StorageDead(_4);                 // scope 3 at $DIR/cycle.rs:+4:9: +4:10
++         nop;                             // scope 1 at $DIR/cycle.rs:+2:9: +2:10
++         nop;                             // scope 1 at $DIR/cycle.rs:+2:13: +2:14
++         nop;                             // scope 2 at $DIR/cycle.rs:+3:9: +3:10
++         nop;                             // scope 2 at $DIR/cycle.rs:+3:13: +3:14
++         nop;                             // scope 3 at $DIR/cycle.rs:+4:9: +4:10
++         nop;                             // scope 3 at $DIR/cycle.rs:+4:9: +4:10
++         nop;                             // scope 3 at $DIR/cycle.rs:+4:5: +4:10
++         nop;                             // scope 3 at $DIR/cycle.rs:+4:9: +4:10
           StorageLive(_5);                 // scope 3 at $DIR/cycle.rs:+6:5: +6:12
-          StorageLive(_6);                 // scope 3 at $DIR/cycle.rs:+6:10: +6:11
-          nop;                             // scope 3 at $DIR/cycle.rs:+6:10: +6:11
-          StorageDead(_6);                 // scope 3 at $DIR/cycle.rs:+6:11: +6:12
+-         StorageLive(_6);                 // scope 3 at $DIR/cycle.rs:+6:10: +6:11
+-         _6 = _1;                         // scope 3 at $DIR/cycle.rs:+6:10: +6:11
++         nop;                             // scope 3 at $DIR/cycle.rs:+6:10: +6:11
++         nop;                             // scope 3 at $DIR/cycle.rs:+6:10: +6:11
+          _5 = std::mem::drop::<i32>(move _6) -> bb2; // scope 3 at $DIR/cycle.rs:+6:5: +6:12
+                                           // mir::Constant
+                                           // + span: $DIR/cycle.rs:14:5: 14:9
+                                           // + literal: Const { ty: fn(i32) {std::mem::drop::<i32>}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+-         StorageDead(_6);                 // scope 3 at $DIR/cycle.rs:+6:11: +6:12
++         nop;                             // scope 3 at $DIR/cycle.rs:+6:11: +6:12
           StorageDead(_5);                 // scope 3 at $DIR/cycle.rs:+6:12: +6:13
-          StorageDead(_3);                 // scope 2 at $DIR/cycle.rs:+7:1: +7:2
-          StorageDead(_2);                 // scope 1 at $DIR/cycle.rs:+7:1: +7:2
-          StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:+7:1: +7:2
+          _0 = const ();                   // scope 0 at $DIR/cycle.rs:+0:11: +7:2
+-         StorageDead(_3);                 // scope 2 at $DIR/cycle.rs:+7:1: +7:2
+-         StorageDead(_2);                 // scope 1 at $DIR/cycle.rs:+7:1: +7:2
+-         StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:+7:1: +7:2
++         nop;                             // scope 2 at $DIR/cycle.rs:+7:1: +7:2
++         nop;                             // scope 1 at $DIR/cycle.rs:+7:1: +7:2
++         nop;                             // scope 0 at $DIR/cycle.rs:+7:1: +7:2
           return;                          // scope 0 at $DIR/cycle.rs:+7:2: +7:2
       }
   }
diff --git a/src/test/mir-opt/dest-prop/cycle.rs b/src/test/mir-opt/dest-prop/cycle.rs
index c9187d408..6182878f3 100644
--- a/src/test/mir-opt/dest-prop/cycle.rs
+++ b/src/test/mir-opt/dest-prop/cycle.rs
@@ -1,5 +1,5 @@
 //! Tests that cyclic assignments don't hang DestinationPropagation, and result in reasonable code.
-// compile-flags: -Zunsound-mir-opts
+// unit-test: DestinationPropagation
 fn val() -> i32 {
     1
 }
diff --git a/src/test/mir-opt/dest-prop/dead_stores_79191.f.DestinationPropagation.after.mir b/src/test/mir-opt/dest-prop/dead_stores_79191.f.DestinationPropagation.after.mir
new file mode 100644
index 000000000..63cac133b
--- /dev/null
+++ b/src/test/mir-opt/dest-prop/dead_stores_79191.f.DestinationPropagation.after.mir
@@ -0,0 +1,34 @@
+// MIR for `f` after DestinationPropagation
+
+fn f(_1: usize) -> usize {
+    debug a => _1;                       // in scope 0 at $DIR/dead_stores_79191.rs:+0:6: +0:11
+    let mut _0: usize;                   // return place in scope 0 at $DIR/dead_stores_79191.rs:+0:23: +0:28
+    let _2: usize;                       // in scope 0 at $DIR/dead_stores_79191.rs:+1:9: +1:10
+    let mut _3: usize;                   // in scope 0 at $DIR/dead_stores_79191.rs:+3:9: +3:10
+    let mut _4: usize;                   // in scope 0 at $DIR/dead_stores_79191.rs:+4:8: +4:9
+    scope 1 {
+        debug b => _3;                   // in scope 1 at $DIR/dead_stores_79191.rs:+1:9: +1:10
+    }
+
+    bb0: {
+        nop;                             // scope 0 at $DIR/dead_stores_79191.rs:+1:9: +1:10
+        _3 = _1;                         // scope 0 at $DIR/dead_stores_79191.rs:+1:13: +1:14
+        _1 = const 5_usize;              // scope 1 at $DIR/dead_stores_79191.rs:+2:5: +2:10
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+3:9: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+3:9: +3:10
+        _1 = move _3;                    // scope 1 at $DIR/dead_stores_79191.rs:+3:5: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+3:9: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+4:8: +4:9
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+4:8: +4:9
+        _0 = id::<usize>(move _1) -> bb1; // scope 1 at $DIR/dead_stores_79191.rs:+4:5: +4:10
+                                         // mir::Constant
+                                         // + span: $DIR/dead_stores_79191.rs:12:5: 12:7
+                                         // + literal: Const { ty: fn(usize) -> usize {id::<usize>}, val: Value(<ZST>) }
+    }
+
+    bb1: {
+        nop;                             // scope 1 at $DIR/dead_stores_79191.rs:+4:9: +4:10
+        nop;                             // scope 0 at $DIR/dead_stores_79191.rs:+5:1: +5:2
+        return;                          // scope 0 at $DIR/dead_stores_79191.rs:+5:2: +5:2
+    }
+}
diff --git a/src/test/mir-opt/dest-prop/dead_stores_79191.rs b/src/test/mir-opt/dest-prop/dead_stores_79191.rs
new file mode 100644
index 000000000..43e0bf664
--- /dev/null
+++ b/src/test/mir-opt/dest-prop/dead_stores_79191.rs
@@ -0,0 +1,17 @@
+// unit-test: DestinationPropagation
+
+fn id<T>(x: T) -> T {
+    x
+}
+
+// EMIT_MIR dead_stores_79191.f.DestinationPropagation.after.mir
+fn f(mut a: usize) -> usize {
+    let b = a;
+    a = 5;
+    a = b;
+    id(a)
+}
+
+fn main() {
+    f(0);
+}
diff --git a/src/test/mir-opt/dest-prop/dead_stores_better.f.DestinationPropagation.after.mir b/src/test/mir-opt/dest-prop/dead_stores_better.f.DestinationPropagation.after.mir
new file mode 100644
index 000000000..ba7f76d28
--- /dev/null
+++ b/src/test/mir-opt/dest-prop/dead_stores_better.f.DestinationPropagation.after.mir
@@ -0,0 +1,34 @@
+// MIR for `f` after DestinationPropagation
+
+fn f(_1: usize) -> usize {
+    debug a => _1;                       // in scope 0 at $DIR/dead_stores_better.rs:+0:10: +0:15
+    let mut _0: usize;                   // return place in scope 0 at $DIR/dead_stores_better.rs:+0:27: +0:32
+    let _2: usize;                       // in scope 0 at $DIR/dead_stores_better.rs:+1:9: +1:10
+    let mut _3: usize;                   // in scope 0 at $DIR/dead_stores_better.rs:+3:9: +3:10
+    let mut _4: usize;                   // in scope 0 at $DIR/dead_stores_better.rs:+4:8: +4:9
+    scope 1 {
+        debug b => _1;                   // in scope 1 at $DIR/dead_stores_better.rs:+1:9: +1:10
+    }
+
+    bb0: {
+        nop;                             // scope 0 at $DIR/dead_stores_better.rs:+1:9: +1:10
+        nop;                             // scope 0 at $DIR/dead_stores_better.rs:+1:13: +1:14
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+2:5: +2:10
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+3:9: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+3:9: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+3:5: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+3:9: +3:10
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+4:8: +4:9
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+4:8: +4:9
+        _0 = id::<usize>(move _1) -> bb1; // scope 1 at $DIR/dead_stores_better.rs:+4:5: +4:10
+                                         // mir::Constant
+                                         // + span: $DIR/dead_stores_better.rs:16:5: 16:7
+                                         // + literal: Const { ty: fn(usize) -> usize {id::<usize>}, val: Value(<ZST>) }
+    }
+
+    bb1: {
+        nop;                             // scope 1 at $DIR/dead_stores_better.rs:+4:9: +4:10
+        nop;                             // scope 0 at $DIR/dead_stores_better.rs:+5:1: +5:2
+        return;                          // scope 0 at $DIR/dead_stores_better.rs:+5:2: +5:2
+    }
+}
diff --git a/src/test/mir-opt/dest-prop/dead_stores_better.rs b/src/test/mir-opt/dest-prop/dead_stores_better.rs
new file mode 100644
index 000000000..003ad57d8
--- /dev/null
+++ b/src/test/mir-opt/dest-prop/dead_stores_better.rs
@@ -0,0 +1,21 @@
+// This is a copy of the `dead_stores_79191` test, except that we turn on DSE. This demonstrates
+// that that pass enables this one to do more optimizations.
+
+// unit-test: DestinationPropagation
+// compile-flags: -Zmir-enable-passes=+DeadStoreElimination
+
+fn id<T>(x: T) -> T {
+    x
+}
+
+// EMIT_MIR dead_stores_better.f.DestinationPropagation.after.mir
+pub fn f(mut a: usize) -> usize {
+    let b = a;
+    a = 5;
+    a = b;
+    id(a)
+}
+
+fn main() {
+    f(0);
+}
diff --git a/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
index 80b09ed5f..c2a3a0025 100644
--- a/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff
@@ -17,18 +17,22 @@
           StorageLive(_2);                 // scope 0 at $DIR/simple.rs:+1:9: +1:16
           _2 = [const 0_u8; 1024];         // scope 0 at $DIR/simple.rs:+1:19: +1:28
           StorageLive(_3);                 // scope 1 at $DIR/simple.rs:+2:5: +2:19
-          StorageLive(_4);                 // scope 1 at $DIR/simple.rs:+2:5: +2:9
-          _4 = _1;                         // scope 1 at $DIR/simple.rs:+2:5: +2:9
+-         StorageLive(_4);                 // scope 1 at $DIR/simple.rs:+2:5: +2:9
+-         _4 = _1;                         // scope 1 at $DIR/simple.rs:+2:5: +2:9
++         nop;                             // scope 1 at $DIR/simple.rs:+2:5: +2:9
++         nop;                             // scope 1 at $DIR/simple.rs:+2:5: +2:9
           StorageLive(_5);                 // scope 1 at $DIR/simple.rs:+2:10: +2:18
           StorageLive(_6);                 // scope 1 at $DIR/simple.rs:+2:10: +2:18
           _6 = &mut _2;                    // scope 1 at $DIR/simple.rs:+2:10: +2:18
           _5 = &mut (*_6);                 // scope 1 at $DIR/simple.rs:+2:10: +2:18
-          _3 = move _4(move _5) -> bb1;    // scope 1 at $DIR/simple.rs:+2:5: +2:19
+-         _3 = move _4(move _5) -> bb1;    // scope 1 at $DIR/simple.rs:+2:5: +2:19
++         _3 = move _1(move _5) -> bb1;    // scope 1 at $DIR/simple.rs:+2:5: +2:19
       }
   
       bb1: {
           StorageDead(_5);                 // scope 1 at $DIR/simple.rs:+2:18: +2:19
-          StorageDead(_4);                 // scope 1 at $DIR/simple.rs:+2:18: +2:19
+-         StorageDead(_4);                 // scope 1 at $DIR/simple.rs:+2:18: +2:19
++         nop;                             // scope 1 at $DIR/simple.rs:+2:18: +2:19
           StorageDead(_6);                 // scope 1 at $DIR/simple.rs:+2:19: +2:20
           StorageDead(_3);                 // scope 1 at $DIR/simple.rs:+2:19: +2:20
           _0 = _2;                         // scope 1 at $DIR/simple.rs:+3:5: +3:8
diff --git a/src/test/mir-opt/dest-prop/simple.rs b/src/test/mir-opt/dest-prop/simple.rs
index 3627d479a..d4c27228f 100644
--- a/src/test/mir-opt/dest-prop/simple.rs
+++ b/src/test/mir-opt/dest-prop/simple.rs
@@ -1,5 +1,5 @@
 //! Copy of `nrvo-simple.rs`, to ensure that full dest-prop handles it too.
-// compile-flags: -Zunsound-mir-opts
+// unit-test: DestinationPropagation
 // EMIT_MIR simple.nrvo.DestinationPropagation.diff
 fn nrvo(init: fn(&mut [u8; 1024])) -> [u8; 1024] {
     let mut buf = [0; 1024];
diff --git a/src/test/mir-opt/dest-prop/union.main.DestinationPropagation.diff b/src/test/mir-opt/dest-prop/union.main.DestinationPropagation.diff
index accdb0085..85d994bc8 100644
--- a/src/test/mir-opt/dest-prop/union.main.DestinationPropagation.diff
+++ b/src/test/mir-opt/dest-prop/union.main.DestinationPropagation.diff
@@ -5,14 +5,13 @@
       let mut _0: ();                      // return place in scope 0 at $DIR/union.rs:+0:11: +0:11
       let _1: main::Un;                    // in scope 0 at $DIR/union.rs:+5:9: +5:11
       let mut _2: u32;                     // in scope 0 at $DIR/union.rs:+5:23: +5:28
-      let _3: ();                          // in scope 0 at $DIR/union.rs:+7:5: +7:27
-      let mut _4: u32;                     // in scope 0 at $DIR/union.rs:+7:10: +7:26
+      let mut _3: u32;                     // in scope 0 at $DIR/union.rs:+7:10: +7:26
       scope 1 {
           debug un => _1;                  // in scope 1 at $DIR/union.rs:+5:9: +5:11
           scope 2 {
           }
           scope 3 (inlined std::mem::drop::<u32>) { // at $DIR/union.rs:15:5: 15:27
-              debug _x => _4;              // in scope 3 at $SRC_DIR/core/src/mem/mod.rs:LL:COL
+              debug _x => _3;              // in scope 3 at $SRC_DIR/core/src/mem/mod.rs:LL:COL
           }
       }
   
@@ -29,11 +28,9 @@
           nop;                             // scope 0 at $DIR/union.rs:+5:14: +5:30
           nop;                             // scope 0 at $DIR/union.rs:+5:14: +5:30
           StorageDead(_2);                 // scope 0 at $DIR/union.rs:+5:29: +5:30
-          StorageLive(_3);                 // scope 1 at $DIR/union.rs:+7:5: +7:27
-          StorageLive(_4);                 // scope 1 at $DIR/union.rs:+7:10: +7:26
+          StorageLive(_3);                 // scope 1 at $DIR/union.rs:+7:10: +7:26
           nop;                             // scope 2 at $DIR/union.rs:+7:19: +7:24
-          StorageDead(_4);                 // scope 1 at $DIR/union.rs:+7:26: +7:27
-          StorageDead(_3);                 // scope 1 at $DIR/union.rs:+7:27: +7:28
+          StorageDead(_3);                 // scope 1 at $DIR/union.rs:+7:26: +7:27
           StorageDead(_1);                 // scope 0 at $DIR/union.rs:+8:1: +8:2
           return;                          // scope 0 at $DIR/union.rs:+8:2: +8:2
       }