Adding upstream version 1.69.0+dfsg1.upstream/1.69.0+dfsg1

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

27 files changed, 911 insertions, 0 deletions

diff --git a/tests/mir-opt/copy-prop/borrowed_local.f.CopyProp.diff b/tests/mir-opt/copy-prop/borrowed_local.f.CopyProp.diff
new file mode 100644
index 000000000..b183865a9
--- /dev/null
+++ b/tests/mir-opt/copy-prop/borrowed_local.f.CopyProp.diff
@@ -0,0 +1,34 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f() -> bool {
+      let mut _0: bool;                    // return place in scope 0 at $DIR/borrowed_local.rs:+0:11: +0:15
+      let mut _1: u8;                      // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _2: &u8;                     // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _3: u8;                      // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _4: &u8;                     // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+  
+      bb0: {
+          _1 = const 5_u8;                 // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _2 = &_1;                        // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _3 = _1;                         // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _4 = &_3;                        // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _0 = cmp_ref(_2, _4) -> bb1;     // scope 0 at $DIR/borrowed_local.rs:+8:13: +8:45
+                                           // mir::Constant
+                                           // + span: $DIR/borrowed_local.rs:23:29: 23:36
+                                           // + literal: Const { ty: for<'a, 'b> fn(&'a u8, &'b u8) -> bool {cmp_ref}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+-         _0 = opaque::<u8>(_3) -> bb2;    // scope 0 at $DIR/borrowed_local.rs:+12:13: +12:38
++         _0 = opaque::<u8>(_1) -> bb2;    // scope 0 at $DIR/borrowed_local.rs:+12:13: +12:38
+                                           // mir::Constant
+                                           // + span: $DIR/borrowed_local.rs:27:28: 27:34
+                                           // + literal: Const { ty: fn(u8) -> bool {opaque::<u8>}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          return;                          // scope 0 at $DIR/borrowed_local.rs:+15:13: +15:21
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/borrowed_local.rs b/tests/mir-opt/copy-prop/borrowed_local.rs
new file mode 100644
index 000000000..c4b980e2b
--- /dev/null
+++ b/tests/mir-opt/copy-prop/borrowed_local.rs
@@ -0,0 +1,39 @@
+// unit-test: CopyProp
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(unused_assignments)]
+extern crate core;
+use core::intrinsics::mir::*;
+
+fn opaque(_: impl Sized) -> bool { true }
+
+fn cmp_ref(a: &u8, b: &u8) -> bool {
+    std::ptr::eq(a as *const u8, b as *const u8)
+}
+
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn f() -> bool {
+    mir!(
+        {
+            let a = 5_u8;
+            let r1 = &a;
+            let b = a;
+            // We cannot propagate the place `a`.
+            let r2 = &b;
+            Call(RET, next, cmp_ref(r1, r2))
+        }
+        next = {
+            // But we can propagate the value `a`.
+            Call(RET, ret, opaque(b))
+        }
+        ret = {
+            Return()
+        }
+    )
+}
+
+fn main() {
+    assert!(!f());
+}
+
+// EMIT_MIR borrowed_local.f.CopyProp.diff
diff --git a/tests/mir-opt/copy-prop/branch.foo.CopyProp.diff b/tests/mir-opt/copy-prop/branch.foo.CopyProp.diff
new file mode 100644
index 000000000..8b116532d
--- /dev/null
+++ b/tests/mir-opt/copy-prop/branch.foo.CopyProp.diff
@@ -0,0 +1,65 @@
+- // MIR for `foo` before CopyProp
++ // MIR for `foo` after CopyProp
+  
+  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
+          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
+          }
+      }
+  
+      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
+                                           // 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(_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
+                                           // + span: $DIR/branch.rs:15:16: 15:20
+                                           // + literal: Const { ty: fn() -> bool {cond}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          switchInt(move _3) -> [0: bb4, otherwise: bb3]; // scope 1 at $DIR/branch.rs:+3:16: +3:22
+      }
+  
+      bb3: {
+          _2 = _1;                         // scope 1 at $DIR/branch.rs:+4:9: +4:10
+          goto -> bb6;                     // scope 1 at $DIR/branch.rs:+3:13: +8:6
+      }
+  
+      bb4: {
+          StorageLive(_4);                 // scope 1 at $DIR/branch.rs:+6:9: +6:14
+          _4 = val() -> bb5;               // scope 1 at $DIR/branch.rs:+6:9: +6:14
+                                           // mir::Constant
+                                           // + span: $DIR/branch.rs:18:9: 18:12
+                                           // + literal: Const { ty: fn() -> i32 {val}, val: Value(<ZST>) }
+      }
+  
+      bb5: {
+          StorageDead(_4);                 // scope 1 at $DIR/branch.rs:+6:14: +6:15
+          _2 = _1;                         // 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
+          _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
+          return;                          // scope 0 at $DIR/branch.rs:+11:2: +11:2
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/branch.rs b/tests/mir-opt/copy-prop/branch.rs
new file mode 100644
index 000000000..50b1e00fa
--- /dev/null
+++ b/tests/mir-opt/copy-prop/branch.rs
@@ -0,0 +1,27 @@
+//! Tests that we bail out when there are multiple assignments to the same local.
+// unit-test: CopyProp
+fn val() -> i32 {
+    1
+}
+
+fn cond() -> bool {
+    true
+}
+
+// EMIT_MIR branch.foo.CopyProp.diff
+fn foo() -> i32 {
+    let x = val();
+
+    let y = if cond() {
+        x
+    } else {
+        val();
+        x
+    };
+
+    y
+}
+
+fn main() {
+    foo();
+}
diff --git a/tests/mir-opt/copy-prop/copy_propagation_arg.arg_src.CopyProp.diff b/tests/mir-opt/copy-prop/copy_propagation_arg.arg_src.CopyProp.diff
new file mode 100644
index 000000000..69acebf76
--- /dev/null
+++ b/tests/mir-opt/copy-prop/copy_propagation_arg.arg_src.CopyProp.diff
@@ -0,0 +1,21 @@
+- // MIR for `arg_src` before CopyProp
++ // MIR for `arg_src` after CopyProp
+  
+  fn arg_src(_1: i32) -> i32 {
+      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 {
+          debug y => _2;                   // in scope 1 at $DIR/copy_propagation_arg.rs:+1:9: +1:10
+      }
+  
+      bb0: {
+          StorageLive(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:9: +1:10
+          _2 = _1;                         // scope 0 at $DIR/copy_propagation_arg.rs:+1:13: +1:14
+          _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
+          return;                          // scope 0 at $DIR/copy_propagation_arg.rs:+4:2: +4:2
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/copy_propagation_arg.bar.CopyProp.diff b/tests/mir-opt/copy-prop/copy_propagation_arg.bar.CopyProp.diff
new file mode 100644
index 000000000..ac4e9a2bf
--- /dev/null
+++ b/tests/mir-opt/copy-prop/copy_propagation_arg.bar.CopyProp.diff
@@ -0,0 +1,28 @@
+- // MIR for `bar` before CopyProp
++ // MIR for `bar` after CopyProp
+  
+  fn bar(_1: u8) -> () {
+      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
+                                           // 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(_2);                 // scope 0 at $DIR/copy_propagation_arg.rs:+1:13: +1:14
+          _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/tests/mir-opt/copy-prop/copy_propagation_arg.baz.CopyProp.diff b/tests/mir-opt/copy-prop/copy_propagation_arg.baz.CopyProp.diff
new file mode 100644
index 000000000..7ab6ebb7d
--- /dev/null
+++ b/tests/mir-opt/copy-prop/copy_propagation_arg.baz.CopyProp.diff
@@ -0,0 +1,18 @@
+- // MIR for `baz` before CopyProp
++ // MIR for `baz` after CopyProp
+  
+  fn baz(_1: i32) -> i32 {
+      debug x => _1;                       // in scope 0 at $DIR/copy_propagation_arg.rs:+0:8: +0:13
+      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
+          _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
+          _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/tests/mir-opt/copy-prop/copy_propagation_arg.foo.CopyProp.diff b/tests/mir-opt/copy-prop/copy_propagation_arg.foo.CopyProp.diff
new file mode 100644
index 000000000..0a3e985e7
--- /dev/null
+++ b/tests/mir-opt/copy-prop/copy_propagation_arg.foo.CopyProp.diff
@@ -0,0 +1,28 @@
+- // MIR for `foo` before CopyProp
++ // MIR for `foo` after CopyProp
+  
+  fn foo(_1: u8) -> () {
+      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 mut _2: u8;                      // in scope 0 at $DIR/copy_propagation_arg.rs:+2:9: +2:17
+      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(_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
+                                           // mir::Constant
+                                           // + span: $DIR/copy_propagation_arg.rs:11:9: 11:14
+                                           // + literal: Const { ty: fn(u8) -> u8 {dummy}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          StorageDead(_3);                 // scope 0 at $DIR/copy_propagation_arg.rs:+2:16: +2:17
+          _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
+          _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/tests/mir-opt/copy-prop/copy_propagation_arg.rs b/tests/mir-opt/copy-prop/copy_propagation_arg.rs
new file mode 100644
index 000000000..cc98985f1
--- /dev/null
+++ b/tests/mir-opt/copy-prop/copy_propagation_arg.rs
@@ -0,0 +1,40 @@
+// Check that CopyProp does not propagate an assignment to a function argument
+// (doing so can break usages of the original argument value)
+// unit-test: CopyProp
+fn dummy(x: u8) -> u8 {
+    x
+}
+
+// EMIT_MIR copy_propagation_arg.foo.CopyProp.diff
+fn foo(mut x: u8) {
+    // calling `dummy` to make a use of `x` that copyprop cannot eliminate
+    x = dummy(x); // this will assign a local to `x`
+}
+
+// EMIT_MIR copy_propagation_arg.bar.CopyProp.diff
+fn bar(mut x: u8) {
+    dummy(x);
+    x = 5;
+}
+
+// EMIT_MIR copy_propagation_arg.baz.CopyProp.diff
+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.CopyProp.diff
+fn arg_src(mut x: i32) -> i32 {
+    let y = x;
+    x = 123; // Don't propagate this assignment to `y`
+    y
+}
+
+fn main() {
+    // Make sure the function actually gets instantiated.
+    foo(0);
+    bar(0);
+    baz(0);
+    arg_src(0);
+}
diff --git a/tests/mir-opt/copy-prop/custom_move_arg.f.CopyProp.diff b/tests/mir-opt/copy-prop/custom_move_arg.f.CopyProp.diff
new file mode 100644
index 000000000..6ca73ffdd
--- /dev/null
+++ b/tests/mir-opt/copy-prop/custom_move_arg.f.CopyProp.diff
@@ -0,0 +1,31 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f(_1: NotCopy) -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/custom_move_arg.rs:+0:19: +0:19
+      let mut _2: NotCopy;                 // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _3: NotCopy;                 // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+  
+      bb0: {
+-         _2 = _1;                         // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+-         _0 = opaque::<NotCopy>(move _1) -> bb1; // scope 0 at $DIR/custom_move_arg.rs:+3:9: +3:41
++         _0 = opaque::<NotCopy>(_1) -> bb1; // scope 0 at $DIR/custom_move_arg.rs:+3:9: +3:41
+                                           // mir::Constant
+                                           // + span: $DIR/custom_move_arg.rs:15:24: 15:30
+                                           // + literal: Const { ty: fn(NotCopy) {opaque::<NotCopy>}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+-         _3 = move _2;                    // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+-         _0 = opaque::<NotCopy>(_3) -> bb2; // scope 0 at $DIR/custom_move_arg.rs:+7:9: +7:35
++         _0 = opaque::<NotCopy>(_1) -> bb2; // scope 0 at $DIR/custom_move_arg.rs:+7:9: +7:35
+                                           // mir::Constant
+                                           // + span: $DIR/custom_move_arg.rs:19:24: 19:30
+                                           // + literal: Const { ty: fn(NotCopy) {opaque::<NotCopy>}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          return;                          // scope 0 at $DIR/custom_move_arg.rs:+10:9: +10:17
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/custom_move_arg.rs b/tests/mir-opt/copy-prop/custom_move_arg.rs
new file mode 100644
index 000000000..4a591146e
--- /dev/null
+++ b/tests/mir-opt/copy-prop/custom_move_arg.rs
@@ -0,0 +1,32 @@
+// unit-test: CopyProp
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(unused_assignments)]
+extern crate core;
+use core::intrinsics::mir::*;
+
+struct NotCopy(bool);
+
+// EMIT_MIR custom_move_arg.f.CopyProp.diff
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn f(_1: NotCopy) {
+    mir!({
+        let _2 = _1;
+        Call(RET, bb1, opaque(Move(_1)))
+    }
+    bb1 = {
+        let _3 = Move(_2);
+        Call(RET, bb2, opaque(_3))
+    }
+    bb2 = {
+        Return()
+    })
+}
+
+#[inline(never)]
+fn opaque<T>(_t: T) {}
+
+fn main() {
+    f(NotCopy(true));
+    println!("hi");
+}
diff --git a/tests/mir-opt/copy-prop/cycle.main.CopyProp.diff b/tests/mir-opt/copy-prop/cycle.main.CopyProp.diff
new file mode 100644
index 000000000..3e61869e8
--- /dev/null
+++ b/tests/mir-opt/copy-prop/cycle.main.CopyProp.diff
@@ -0,0 +1,60 @@
+- // MIR for `main` before CopyProp
++ // MIR for `main` after CopyProp
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/cycle.rs:+0:11: +0:11
+      let mut _1: i32;                     // in scope 0 at $DIR/cycle.rs:+1:9: +1:14
+      let mut _4: i32;                     // in scope 0 at $DIR/cycle.rs:+4:9: +4:10
+      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
+          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
+              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
++                 debug z => _2;           // 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
+                                           // 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
+          _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
++         _1 = _2;                         // scope 3 at $DIR/cycle.rs:+4:5: +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
+          _6 = _1;                         // 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
+          StorageDead(_5);                 // scope 3 at $DIR/cycle.rs:+6:12: +6:13
+          _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
+          return;                          // scope 0 at $DIR/cycle.rs:+7:2: +7:2
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/cycle.rs b/tests/mir-opt/copy-prop/cycle.rs
new file mode 100644
index 000000000..b74c39726
--- /dev/null
+++ b/tests/mir-opt/copy-prop/cycle.rs
@@ -0,0 +1,15 @@
+//! Tests that cyclic assignments don't hang CopyProp, and result in reasonable code.
+// unit-test: CopyProp
+fn val() -> i32 {
+    1
+}
+
+// EMIT_MIR cycle.main.CopyProp.diff
+fn main() {
+    let mut x = val();
+    let y = x;
+    let z = y;
+    x = z;
+
+    drop(x);
+}
diff --git a/tests/mir-opt/copy-prop/dead_stores_79191.f.CopyProp.after.mir b/tests/mir-opt/copy-prop/dead_stores_79191.f.CopyProp.after.mir
new file mode 100644
index 000000000..d48b04e2d
--- /dev/null
+++ b/tests/mir-opt/copy-prop/dead_stores_79191.f.CopyProp.after.mir
@@ -0,0 +1,29 @@
+// MIR for `f` after CopyProp
+
+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 => _2;                   // in scope 1 at $DIR/dead_stores_79191.rs:+1:9: +1:10
+    }
+
+    bb0: {
+        _2 = _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
+        _1 = _2;                         // scope 1 at $DIR/dead_stores_79191.rs:+3:5: +3:10
+        StorageLive(_4);                 // scope 1 at $DIR/dead_stores_79191.rs:+4:8: +4:9
+        _4 = _1;                         // scope 1 at $DIR/dead_stores_79191.rs:+4:8: +4:9
+        _0 = id::<usize>(move _4) -> 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: {
+        StorageDead(_4);                 // scope 1 at $DIR/dead_stores_79191.rs:+4:9: +4:10
+        return;                          // scope 0 at $DIR/dead_stores_79191.rs:+5:2: +5:2
+    }
+}
diff --git a/tests/mir-opt/copy-prop/dead_stores_79191.rs b/tests/mir-opt/copy-prop/dead_stores_79191.rs
new file mode 100644
index 000000000..e3493b8b7
--- /dev/null
+++ b/tests/mir-opt/copy-prop/dead_stores_79191.rs
@@ -0,0 +1,17 @@
+// unit-test: CopyProp
+
+fn id<T>(x: T) -> T {
+    x
+}
+
+// EMIT_MIR dead_stores_79191.f.CopyProp.after.mir
+fn f(mut a: usize) -> usize {
+    let b = a;
+    a = 5;
+    a = b;
+    id(a)
+}
+
+fn main() {
+    f(0);
+}
diff --git a/tests/mir-opt/copy-prop/dead_stores_better.f.CopyProp.after.mir b/tests/mir-opt/copy-prop/dead_stores_better.f.CopyProp.after.mir
new file mode 100644
index 000000000..727791f50
--- /dev/null
+++ b/tests/mir-opt/copy-prop/dead_stores_better.f.CopyProp.after.mir
@@ -0,0 +1,29 @@
+// MIR for `f` after CopyProp
+
+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 => _2;                   // in scope 1 at $DIR/dead_stores_better.rs:+1:9: +1:10
+    }
+
+    bb0: {
+        _2 = _1;                         // scope 0 at $DIR/dead_stores_better.rs:+1:13: +1:14
+        _1 = const 5_usize;              // scope 1 at $DIR/dead_stores_better.rs:+2:5: +2:10
+        _1 = _2;                         // scope 1 at $DIR/dead_stores_better.rs:+3:5: +3:10
+        StorageLive(_4);                 // scope 1 at $DIR/dead_stores_better.rs:+4:8: +4:9
+        _4 = _1;                         // scope 1 at $DIR/dead_stores_better.rs:+4:8: +4:9
+        _0 = id::<usize>(move _4) -> 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: {
+        StorageDead(_4);                 // scope 1 at $DIR/dead_stores_better.rs:+4:9: +4:10
+        return;                          // scope 0 at $DIR/dead_stores_better.rs:+5:2: +5:2
+    }
+}
diff --git a/tests/mir-opt/copy-prop/dead_stores_better.rs b/tests/mir-opt/copy-prop/dead_stores_better.rs
new file mode 100644
index 000000000..8465b3c98
--- /dev/null
+++ b/tests/mir-opt/copy-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: CopyProp
+// compile-flags: -Zmir-enable-passes=+DeadStoreElimination
+
+fn id<T>(x: T) -> T {
+    x
+}
+
+// EMIT_MIR dead_stores_better.f.CopyProp.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/tests/mir-opt/copy-prop/issue_107511.main.CopyProp.diff b/tests/mir-opt/copy-prop/issue_107511.main.CopyProp.diff
new file mode 100644
index 000000000..97d0a01e0
--- /dev/null
+++ b/tests/mir-opt/copy-prop/issue_107511.main.CopyProp.diff
@@ -0,0 +1,138 @@
+- // MIR for `main` before CopyProp
++ // MIR for `main` after CopyProp
+  
+  fn main() -> () {
+      let mut _0: ();                      // return place in scope 0 at $DIR/issue_107511.rs:+0:11: +0:11
+      let mut _1: i32;                     // in scope 0 at $DIR/issue_107511.rs:+1:9: +1:16
+      let mut _3: std::ops::Range<usize>;  // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _4: std::ops::Range<usize>;  // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _5: usize;                   // in scope 0 at $DIR/issue_107511.rs:+6:17: +6:24
+      let mut _6: &[i32];                  // in scope 0 at $DIR/issue_107511.rs:+6:17: +6:24
+      let mut _7: &[i32; 4];               // in scope 0 at $DIR/issue_107511.rs:+6:17: +6:24
+      let mut _9: ();                      // in scope 0 at $DIR/issue_107511.rs:+0:1: +9:2
+      let _10: ();                         // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _11: std::option::Option<usize>; // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _12: &mut std::ops::Range<usize>; // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _13: &mut std::ops::Range<usize>; // in scope 0 at $DIR/issue_107511.rs:+6:14: +6:24
+      let mut _14: isize;                  // in scope 0 at $DIR/issue_107511.rs:+6:5: +8:6
+      let mut _15: !;                      // in scope 0 at $DIR/issue_107511.rs:+6:5: +8:6
+      let mut _17: i32;                    // in scope 0 at $DIR/issue_107511.rs:+7:16: +7:20
+      let _18: usize;                      // in scope 0 at $DIR/issue_107511.rs:+7:18: +7:19
+      let mut _19: usize;                  // in scope 0 at $DIR/issue_107511.rs:+7:16: +7:20
+      let mut _20: bool;                   // in scope 0 at $DIR/issue_107511.rs:+7:16: +7:20
+      scope 1 {
+          debug sum => _1;                 // in scope 1 at $DIR/issue_107511.rs:+1:9: +1:16
+          let _2: [i32; 4];                // in scope 1 at $DIR/issue_107511.rs:+2:9: +2:10
+          scope 2 {
+              debug a => _2;               // in scope 2 at $DIR/issue_107511.rs:+2:9: +2:10
+              let mut _8: std::ops::Range<usize>; // in scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+              scope 3 {
+                  debug iter => _8;        // in scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+                  let _16: usize;          // in scope 3 at $DIR/issue_107511.rs:+6:9: +6:10
+                  scope 4 {
+                      debug i => _16;      // in scope 4 at $DIR/issue_107511.rs:+6:9: +6:10
+                  }
+              }
+          }
+      }
+  
+      bb0: {
+          StorageLive(_1);                 // scope 0 at $DIR/issue_107511.rs:+1:9: +1:16
+          _1 = const 0_i32;                // scope 0 at $DIR/issue_107511.rs:+1:19: +1:20
+          StorageLive(_2);                 // scope 1 at $DIR/issue_107511.rs:+2:9: +2:10
+          _2 = [const 0_i32, const 10_i32, const 20_i32, const 30_i32]; // scope 1 at $DIR/issue_107511.rs:+2:13: +2:28
+          StorageLive(_3);                 // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageLive(_4);                 // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageLive(_5);                 // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+          StorageLive(_6);                 // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+          StorageLive(_7);                 // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+          _7 = &_2;                        // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+          _6 = move _7 as &[i32] (Pointer(Unsize)); // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+          StorageDead(_7);                 // scope 2 at $DIR/issue_107511.rs:+6:17: +6:18
+          _5 = core::slice::<impl [i32]>::len(move _6) -> bb1; // scope 2 at $DIR/issue_107511.rs:+6:17: +6:24
+                                           // mir::Constant
+                                           // + span: $DIR/issue_107511.rs:10:19: 10:22
+                                           // + literal: Const { ty: for<'a> fn(&'a [i32]) -> usize {core::slice::<impl [i32]>::len}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          StorageDead(_6);                 // scope 2 at $DIR/issue_107511.rs:+6:23: +6:24
+          _4 = std::ops::Range::<usize> { start: const 0_usize, end: move _5 }; // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageDead(_5);                 // scope 2 at $DIR/issue_107511.rs:+6:23: +6:24
+          _3 = <std::ops::Range<usize> as IntoIterator>::into_iter(move _4) -> bb2; // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+                                           // mir::Constant
+                                           // + span: $DIR/issue_107511.rs:10:14: 10:24
+                                           // + literal: Const { ty: fn(std::ops::Range<usize>) -> <std::ops::Range<usize> as IntoIterator>::IntoIter {<std::ops::Range<usize> as IntoIterator>::into_iter}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          StorageDead(_4);                 // scope 2 at $DIR/issue_107511.rs:+6:23: +6:24
+          StorageLive(_8);                 // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+          _8 = move _3;                    // scope 2 at $DIR/issue_107511.rs:+6:14: +6:24
+          goto -> bb3;                     // scope 3 at $DIR/issue_107511.rs:+6:5: +8:6
+      }
+  
+      bb3: {
+-         StorageLive(_10);                // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageLive(_11);                // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageLive(_12);                // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          StorageLive(_13);                // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          _13 = &mut _8;                   // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          _12 = &mut (*_13);               // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          _11 = <std::ops::Range<usize> as Iterator>::next(move _12) -> bb4; // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+                                           // mir::Constant
+                                           // + span: $DIR/issue_107511.rs:10:14: 10:24
+                                           // + literal: Const { ty: for<'a> fn(&'a mut std::ops::Range<usize>) -> Option<<std::ops::Range<usize> as Iterator>::Item> {<std::ops::Range<usize> as Iterator>::next}, val: Value(<ZST>) }
+      }
+  
+      bb4: {
+          StorageDead(_12);                // scope 3 at $DIR/issue_107511.rs:+6:23: +6:24
+          _14 = discriminant(_11);         // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+          switchInt(move _14) -> [0: bb7, 1: bb5, otherwise: bb6]; // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+      }
+  
+      bb5: {
+-         StorageLive(_16);                // scope 3 at $DIR/issue_107511.rs:+6:9: +6:10
+          _16 = ((_11 as Some).0: usize);  // scope 3 at $DIR/issue_107511.rs:+6:9: +6:10
+          StorageLive(_17);                // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
+-         StorageLive(_18);                // scope 4 at $DIR/issue_107511.rs:+7:18: +7:19
+-         _18 = _16;                       // scope 4 at $DIR/issue_107511.rs:+7:18: +7:19
+          _19 = Len(_2);                   // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
+-         _20 = Lt(_18, _19);              // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
+-         assert(move _20, "index out of bounds: the length is {} but the index is {}", move _19, _18) -> bb8; // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
++         _20 = Lt(_16, _19);              // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
++         assert(move _20, "index out of bounds: the length is {} but the index is {}", move _19, _16) -> bb8; // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
+      }
+  
+      bb6: {
+          unreachable;                     // scope 3 at $DIR/issue_107511.rs:+6:14: +6:24
+      }
+  
+      bb7: {
+          _0 = const ();                   // scope 3 at $DIR/issue_107511.rs:+6:5: +8:6
+          StorageDead(_13);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_11);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+-         StorageDead(_10);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_8);                 // scope 2 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_3);                 // scope 2 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_2);                 // scope 1 at $DIR/issue_107511.rs:+9:1: +9:2
+          StorageDead(_1);                 // scope 0 at $DIR/issue_107511.rs:+9:1: +9:2
+          return;                          // scope 0 at $DIR/issue_107511.rs:+9:2: +9:2
+      }
+  
+      bb8: {
+-         _17 = _2[_18];                   // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
++         _17 = _2[_16];                   // scope 4 at $DIR/issue_107511.rs:+7:16: +7:20
+          _1 = Add(_1, move _17);          // scope 4 at $DIR/issue_107511.rs:+7:9: +7:20
+          StorageDead(_17);                // scope 4 at $DIR/issue_107511.rs:+7:19: +7:20
+-         StorageDead(_18);                // scope 4 at $DIR/issue_107511.rs:+7:20: +7:21
+-         _10 = const ();                  // scope 4 at $DIR/issue_107511.rs:+6:25: +8:6
+-         StorageDead(_16);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_13);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+          StorageDead(_11);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+-         StorageDead(_10);                // scope 3 at $DIR/issue_107511.rs:+8:5: +8:6
+-         _9 = const ();                   // scope 3 at $DIR/issue_107511.rs:+6:5: +8:6
+          goto -> bb3;                     // scope 3 at $DIR/issue_107511.rs:+6:5: +8:6
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/issue_107511.rs b/tests/mir-opt/copy-prop/issue_107511.rs
new file mode 100644
index 000000000..d593f2872
--- /dev/null
+++ b/tests/mir-opt/copy-prop/issue_107511.rs
@@ -0,0 +1,13 @@
+// unit-test: CopyProp
+
+// EMIT_MIR issue_107511.main.CopyProp.diff
+fn main() {
+    let mut sum = 0;
+    let a = [0, 10, 20, 30];
+
+    // `i` is assigned in a loop. Only removing its `StorageDead` would mean that
+    // execution sees repeated `StorageLive`. This would be UB.
+    for i in 0..a.len() {
+        sum += a[i];
+    }
+}
diff --git a/tests/mir-opt/copy-prop/move_arg.f.CopyProp.diff b/tests/mir-opt/copy-prop/move_arg.f.CopyProp.diff
new file mode 100644
index 000000000..d76bf1cfe
--- /dev/null
+++ b/tests/mir-opt/copy-prop/move_arg.f.CopyProp.diff
@@ -0,0 +1,40 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f(_1: T) -> () {
+      debug a => _1;                       // in scope 0 at $DIR/move_arg.rs:+0:19: +0:20
+      let mut _0: ();                      // return place in scope 0 at $DIR/move_arg.rs:+0:25: +0:25
+      let _2: T;                           // in scope 0 at $DIR/move_arg.rs:+1:9: +1:10
+      let _3: ();                          // in scope 0 at $DIR/move_arg.rs:+2:5: +2:12
+      let mut _4: T;                       // in scope 0 at $DIR/move_arg.rs:+2:7: +2:8
+      let mut _5: T;                       // in scope 0 at $DIR/move_arg.rs:+2:10: +2:11
+      scope 1 {
+-         debug b => _2;                   // in scope 1 at $DIR/move_arg.rs:+1:9: +1:10
++         debug b => _1;                   // in scope 1 at $DIR/move_arg.rs:+1:9: +1:10
+      }
+  
+      bb0: {
+-         StorageLive(_2);                 // scope 0 at $DIR/move_arg.rs:+1:9: +1:10
+-         _2 = _1;                         // scope 0 at $DIR/move_arg.rs:+1:13: +1:14
+          StorageLive(_3);                 // scope 1 at $DIR/move_arg.rs:+2:5: +2:12
+-         StorageLive(_4);                 // scope 1 at $DIR/move_arg.rs:+2:7: +2:8
+-         _4 = _1;                         // scope 1 at $DIR/move_arg.rs:+2:7: +2:8
+-         StorageLive(_5);                 // scope 1 at $DIR/move_arg.rs:+2:10: +2:11
+-         _5 = _2;                         // scope 1 at $DIR/move_arg.rs:+2:10: +2:11
+-         _3 = g::<T>(move _4, move _5) -> bb1; // scope 1 at $DIR/move_arg.rs:+2:5: +2:12
++         _3 = g::<T>(_1, _1) -> bb1;      // scope 1 at $DIR/move_arg.rs:+2:5: +2:12
+                                           // mir::Constant
+                                           // + span: $DIR/move_arg.rs:7:5: 7:6
+                                           // + literal: Const { ty: fn(T, T) {g::<T>}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+-         StorageDead(_5);                 // scope 1 at $DIR/move_arg.rs:+2:11: +2:12
+-         StorageDead(_4);                 // scope 1 at $DIR/move_arg.rs:+2:11: +2:12
+          StorageDead(_3);                 // scope 1 at $DIR/move_arg.rs:+2:12: +2:13
+          _0 = const ();                   // scope 0 at $DIR/move_arg.rs:+0:25: +3:2
+-         StorageDead(_2);                 // scope 0 at $DIR/move_arg.rs:+3:1: +3:2
+          return;                          // scope 0 at $DIR/move_arg.rs:+3:2: +3:2
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/move_arg.rs b/tests/mir-opt/copy-prop/move_arg.rs
new file mode 100644
index 000000000..40ae1d8f4
--- /dev/null
+++ b/tests/mir-opt/copy-prop/move_arg.rs
@@ -0,0 +1,15 @@
+// Test that we do not move multiple times from the same local.
+// unit-test: CopyProp
+
+// EMIT_MIR move_arg.f.CopyProp.diff
+pub fn f<T: Copy>(a: T) {
+    let b = a;
+    g(a, b);
+}
+
+#[inline(never)]
+pub fn g<T: Copy>(_: T, _: T) {}
+
+fn main() {
+    f(5)
+}
diff --git a/tests/mir-opt/copy-prop/move_projection.f.CopyProp.diff b/tests/mir-opt/copy-prop/move_projection.f.CopyProp.diff
new file mode 100644
index 000000000..02308beb8
--- /dev/null
+++ b/tests/mir-opt/copy-prop/move_projection.f.CopyProp.diff
@@ -0,0 +1,31 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f(_1: Foo) -> bool {
+      let mut _0: bool;                    // return place in scope 0 at $DIR/move_projection.rs:+0:17: +0:21
+      let mut _2: Foo;                     // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _3: u8;                      // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+  
+      bb0: {
+-         _2 = _1;                         // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+-         _3 = move (_2.0: u8);            // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+-         _0 = opaque::<Foo>(move _1) -> bb1; // scope 0 at $DIR/move_projection.rs:+6:13: +6:44
++         _3 = (_1.0: u8);                 // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
++         _0 = opaque::<Foo>(_1) -> bb1;   // scope 0 at $DIR/move_projection.rs:+6:13: +6:44
+                                           // mir::Constant
+                                           // + span: $DIR/move_projection.rs:19:28: 19:34
+                                           // + literal: Const { ty: fn(Foo) -> bool {opaque::<Foo>}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
+          _0 = opaque::<u8>(move _3) -> bb2; // scope 0 at $DIR/move_projection.rs:+9:13: +9:44
+                                           // mir::Constant
+                                           // + span: $DIR/move_projection.rs:22:28: 22:34
+                                           // + literal: Const { ty: fn(u8) -> bool {opaque::<u8>}, val: Value(<ZST>) }
+      }
+  
+      bb2: {
+          return;                          // scope 0 at $DIR/move_projection.rs:+12:13: +12:21
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/move_projection.rs b/tests/mir-opt/copy-prop/move_projection.rs
new file mode 100644
index 000000000..2a1bbae99
--- /dev/null
+++ b/tests/mir-opt/copy-prop/move_projection.rs
@@ -0,0 +1,34 @@
+// unit-test: CopyProp
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(unused_assignments)]
+extern crate core;
+use core::intrinsics::mir::*;
+
+fn opaque(_: impl Sized) -> bool { true }
+
+struct Foo(u8);
+
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn f(a: Foo) -> bool {
+    mir!(
+        {
+            let b = a;
+            // This is a move out of a copy, so must become a copy of `a.0`.
+            let c = Move(b.0);
+            Call(RET, bb1, opaque(Move(a)))
+        }
+        bb1 = {
+            Call(RET, ret, opaque(Move(c)))
+        }
+        ret = {
+            Return()
+        }
+    )
+}
+
+fn main() {
+    assert!(f(Foo(0)));
+}
+
+// EMIT_MIR move_projection.f.CopyProp.diff
diff --git a/tests/mir-opt/copy-prop/mutate_through_pointer.f.CopyProp.diff b/tests/mir-opt/copy-prop/mutate_through_pointer.f.CopyProp.diff
new file mode 100644
index 000000000..61fdd6f8c
--- /dev/null
+++ b/tests/mir-opt/copy-prop/mutate_through_pointer.f.CopyProp.diff
@@ -0,0 +1,19 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f(_1: bool) -> bool {
+      let mut _0: bool;                    // return place in scope 0 at $DIR/mutate_through_pointer.rs:+0:18: +0:22
+      let mut _2: bool;                    // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _3: *const bool;             // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _4: *mut bool;               // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+  
+      bb0: {
+          _2 = _1;                         // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _3 = &raw const _2;              // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          _4 = &raw mut (*_3);             // scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+          (*_4) = const false;             // scope 0 at $DIR/mutate_through_pointer.rs:+5:9: +5:20
+          _0 = _1;                         // scope 0 at $DIR/mutate_through_pointer.rs:+6:9: +6:16
+          return;                          // scope 0 at $DIR/mutate_through_pointer.rs:+7:9: +7:17
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/mutate_through_pointer.rs b/tests/mir-opt/copy-prop/mutate_through_pointer.rs
new file mode 100644
index 000000000..da142e339
--- /dev/null
+++ b/tests/mir-opt/copy-prop/mutate_through_pointer.rs
@@ -0,0 +1,32 @@
+// This attempts to mutate `a` via a pointer derived from `addr_of!(a)`. That is UB
+// according to Miri. However, the decision to make this UB - and to allow
+// rustc to rely on that fact for the purpose of optimizations - has not been
+// finalized.
+//
+// As such, we include this test to ensure that copy prop does not rely on that
+// fact. Specifically, if `addr_of!(a)` could not be used to modify a, it would
+// be correct for CopyProp to replace all occurrences of `a` with `c` - but that
+// would cause `f(true)` to output `false` instead of `true`.
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(unused_assignments)]
+extern crate core;
+use core::intrinsics::mir::*;
+
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn f(c: bool) -> bool {
+    mir!({
+        let a = c;
+        let p = core::ptr::addr_of!(a);
+        let p2 = core::ptr::addr_of_mut!(*p);
+        *p2 = false;
+        RET = c;
+        Return()
+    })
+}
+
+fn main() {
+    assert_eq!(true, f(true));
+}
+
+// EMIT_MIR mutate_through_pointer.f.CopyProp.diff
diff --git a/tests/mir-opt/copy-prop/non_dominate.f.CopyProp.diff b/tests/mir-opt/copy-prop/non_dominate.f.CopyProp.diff
new file mode 100644
index 000000000..9760fd374
--- /dev/null
+++ b/tests/mir-opt/copy-prop/non_dominate.f.CopyProp.diff
@@ -0,0 +1,29 @@
+- // MIR for `f` before CopyProp
++ // MIR for `f` after CopyProp
+  
+  fn f(_1: bool) -> bool {
+      let mut _0: bool;                    // return place in scope 0 at $DIR/non_dominate.rs:+0:18: +0:22
+      let mut _2: bool;                    // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+      let mut _3: bool;                    // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
+  
+      bb0: {
+          goto -> bb1;                     // scope 0 at $DIR/non_dominate.rs:+4:11: +4:20
+      }
+  
+      bb1: {
+          _3 = _1;                         // scope 0 at $DIR/non_dominate.rs:+5:17: +5:22
+          switchInt(_3) -> [0: bb3, otherwise: bb2]; // scope 0 at $DIR/non_dominate.rs:+5:24: +5:58
+      }
+  
+      bb2: {
+          _2 = _3;                         // scope 0 at $DIR/non_dominate.rs:+8:17: +8:22
+          _1 = const false;                // scope 0 at $DIR/non_dominate.rs:+8:24: +8:33
+          goto -> bb1;                     // scope 0 at $DIR/non_dominate.rs:+8:35: +8:44
+      }
+  
+      bb3: {
+          _0 = _2;                         // scope 0 at $DIR/non_dominate.rs:+9:17: +9:24
+          return;                          // scope 0 at $DIR/non_dominate.rs:+9:26: +9:34
+      }
+  }
+  
diff --git a/tests/mir-opt/copy-prop/non_dominate.rs b/tests/mir-opt/copy-prop/non_dominate.rs
new file mode 100644
index 000000000..c0ea838e1
--- /dev/null
+++ b/tests/mir-opt/copy-prop/non_dominate.rs
@@ -0,0 +1,26 @@
+// unit-test: CopyProp
+
+#![feature(custom_mir, core_intrinsics)]
+#![allow(unused_assignments)]
+extern crate core;
+use core::intrinsics::mir::*;
+
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn f(c: bool) -> bool {
+    mir!(
+        let a: bool;
+        let b: bool;
+        { Goto(bb1) }
+        bb1 = { b = c; match b { false => bb3, _ => bb2 }}
+        // This assignment to `a` does not dominate the use in `bb3`.
+        // It should not be replaced by `b`.
+        bb2 = { a = b; c = false; Goto(bb1) }
+        bb3 = { RET = a; Return() }
+    )
+}
+
+fn main() {
+    assert_eq!(true, f(true));
+}
+
+// EMIT_MIR non_dominate.f.CopyProp.diff