Add tests.

tests/mir-opt/copy-prop/borrowed_local.borrowed.CopyProp.panic-abort.diff

@@ -0,0 +1,23 @@
+- // MIR for `borrowed` before CopyProp
++ // MIR for `borrowed` after CopyProp
+  
+  fn borrowed(_1: u32) -> bool {
+      let mut _0: bool;
+      let mut _2: u32;
+      let mut _3: &u32;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&u32>(_3) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          _0 = opaque::<u32>(_2) -> [return: bb2, unwind unreachable];
+      }
+  
+      bb2: {
+          return;
+      }
+  }
+  

tests/mir-opt/copy-prop/borrowed_local.borrowed.CopyProp.panic-unwind.diff

@@ -0,0 +1,23 @@
+- // MIR for `borrowed` before CopyProp
++ // MIR for `borrowed` after CopyProp
+  
+  fn borrowed(_1: u32) -> bool {
+      let mut _0: bool;
+      let mut _2: u32;
+      let mut _3: &u32;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&u32>(_3) -> [return: bb1, unwind continue];
+      }
+  
+      bb1: {
+          _0 = opaque::<u32>(_2) -> [return: bb2, unwind continue];
+      }
+  
+      bb2: {
+          return;
+      }
+  }
+  

tests/mir-opt/copy-prop/borrowed_local.compare_address.CopyProp.panic-abort.diff

@@ -1,7 +1,7 @@
-- // MIR for `f` before CopyProp
+- // MIR for `compare_address` before CopyProp
-+ // MIR for `f` after CopyProp
++ // MIR for `compare_address` after CopyProp
   
-  fn f() -> bool {
+  fn compare_address() -> bool {
       let mut _0: bool;
       let mut _1: u8;
       let mut _2: &u8;

tests/mir-opt/copy-prop/borrowed_local.compare_address.CopyProp.panic-unwind.diff

@@ -1,7 +1,7 @@
-- // MIR for `f` before CopyProp
+- // MIR for `compare_address` before CopyProp
-+ // MIR for `f` after CopyProp
++ // MIR for `compare_address` after CopyProp
   
-  fn f() -> bool {
+  fn compare_address() -> bool {
       let mut _0: bool;
       let mut _1: u8;
       let mut _2: &u8;

tests/mir-opt/copy-prop/borrowed_local.non_freeze.CopyProp.panic-abort.diff

@@ -0,0 +1,23 @@
+- // MIR for `non_freeze` before CopyProp
++ // MIR for `non_freeze` after CopyProp
+  
+  fn non_freeze(_1: T) -> bool {
+      let mut _0: bool;
+      let mut _2: T;
+      let mut _3: &T;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&T>(_3) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          _0 = opaque::<T>(_2) -> [return: bb2, unwind unreachable];
+      }
+  
+      bb2: {
+          return;
+      }
+  }
+  

tests/mir-opt/copy-prop/borrowed_local.non_freeze.CopyProp.panic-unwind.diff

@@ -0,0 +1,23 @@
+- // MIR for `non_freeze` before CopyProp
++ // MIR for `non_freeze` after CopyProp
+  
+  fn non_freeze(_1: T) -> bool {
+      let mut _0: bool;
+      let mut _2: T;
+      let mut _3: &T;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&T>(_3) -> [return: bb1, unwind continue];
+      }
+  
+      bb1: {
+          _0 = opaque::<T>(_2) -> [return: bb2, unwind continue];
+      }
+  
+      bb2: {
+          return;
+      }
+  }
+  

tests/mir-opt/copy-prop/borrowed_local.rs

@@ -1,4 +1,3 @@
-// skip-filecheck
 // EMIT_MIR_FOR_EACH_PANIC_STRATEGY
 //@ unit-test: CopyProp
 
@@ -14,7 +13,16 @@ fn cmp_ref(a: &u8, b: &u8) -> bool {
 }
 
 #[custom_mir(dialect = "analysis", phase = "post-cleanup")]
-fn f() -> bool {
+fn compare_address() -> bool {
+    // CHECK-LABEL: fn compare_address(
+    // CHECK: bb0: {
+    // CHECK-NEXT: _1 = const 5_u8;
+    // CHECK-NEXT: _2 = &_1;
+    // CHECK-NEXT: _3 = _1;
+    // CHECK-NEXT: _4 = &_3;
+    // CHECK-NEXT: _0 = cmp_ref(_2, _4)
+    // CHECK: bb1: {
+    // CHECK-NEXT: _0 = opaque::<u8>(_3)
     mir!(
         {
             let a = 5_u8;
@@ -34,8 +42,60 @@ fn f() -> bool {
     )
 }
 
-fn main() {
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
-    assert!(!f());
+fn borrowed(x: u32) -> bool {
+    // CHECK-LABEL: fn borrowed(
+    // CHECK: bb0: {
+    // CHECK-NEXT: _2 = _1;
+    // CHECK-NEXT: _3 = &_1;
+    // CHECK-NEXT: _0 = opaque::<&u32>(_3)
+    // CHECK: bb1: {
+    // CHECK-NEXT: _0 = opaque::<u32>(_2)
+    mir!(
+        {
+            let a = x;
+            let r1 = &x;
+            Call(RET = opaque(r1), ReturnTo(next), UnwindContinue())
+        }
+        next = {
+            Call(RET = opaque(a), ReturnTo(ret), UnwindContinue())
+        }
+        ret = {
+            Return()
+        }
+    )
 }
 
-// EMIT_MIR borrowed_local.f.CopyProp.diff
+/// Generic type `T` is not known to be `Freeze`, so shared borrows may be mutable.
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn non_freeze<T: Copy>(x: T) -> bool {
+    // CHECK-LABEL: fn non_freeze(
+    // CHECK: bb0: {
+    // CHECK-NEXT: _2 = _1;
+    // CHECK-NEXT: _3 = &_1;
+    // CHECK-NEXT: _0 = opaque::<&T>(_3)
+    // CHECK: bb1: {
+    // CHECK-NEXT: _0 = opaque::<T>(_2)
+    mir!(
+        {
+            let a = x;
+            let r1 = &x;
+            Call(RET = opaque(r1), ReturnTo(next), UnwindContinue())
+        }
+        next = {
+            Call(RET = opaque(a), ReturnTo(ret), UnwindContinue())
+        }
+        ret = {
+            Return()
+        }
+    )
+}
+
+fn main() {
+    assert!(!compare_address());
+    non_freeze(5);
+}
+
+// EMIT_MIR borrowed_local.compare_address.CopyProp.diff
+// EMIT_MIR borrowed_local.borrowed.CopyProp.diff
+// EMIT_MIR borrowed_local.non_freeze.CopyProp.diff

tests/mir-opt/gvn.borrowed.GVN.panic-abort.diff

@@ -0,0 +1,27 @@
+- // MIR for `borrowed` before GVN
++ // MIR for `borrowed` after GVN
+  
+  fn borrowed(_1: u32) -> () {
+      let mut _0: ();
+      let mut _2: u32;
+      let mut _3: &u32;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&u32>(_3) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          _0 = opaque::<u32>(_2) -> [return: bb2, unwind unreachable];
+      }
+  
+      bb2: {
+          _0 = opaque::<u32>((*_3)) -> [return: bb3, unwind unreachable];
+      }
+  
+      bb3: {
+          return;
+      }
+  }
+  

tests/mir-opt/gvn.borrowed.GVN.panic-unwind.diff

@@ -0,0 +1,27 @@
+- // MIR for `borrowed` before GVN
++ // MIR for `borrowed` after GVN
+  
+  fn borrowed(_1: u32) -> () {
+      let mut _0: ();
+      let mut _2: u32;
+      let mut _3: &u32;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&u32>(_3) -> [return: bb1, unwind continue];
+      }
+  
+      bb1: {
+          _0 = opaque::<u32>(_2) -> [return: bb2, unwind continue];
+      }
+  
+      bb2: {
+          _0 = opaque::<u32>((*_3)) -> [return: bb3, unwind continue];
+      }
+  
+      bb3: {
+          return;
+      }
+  }
+  

tests/mir-opt/gvn.non_freeze.GVN.panic-abort.diff

@@ -0,0 +1,27 @@
+- // MIR for `non_freeze` before GVN
++ // MIR for `non_freeze` after GVN
+  
+  fn non_freeze(_1: T) -> () {
+      let mut _0: ();
+      let mut _2: T;
+      let mut _3: &T;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&T>(_3) -> [return: bb1, unwind unreachable];
+      }
+  
+      bb1: {
+          _0 = opaque::<T>(_2) -> [return: bb2, unwind unreachable];
+      }
+  
+      bb2: {
+          _0 = opaque::<T>((*_3)) -> [return: bb3, unwind unreachable];
+      }
+  
+      bb3: {
+          return;
+      }
+  }
+  

tests/mir-opt/gvn.non_freeze.GVN.panic-unwind.diff

@@ -0,0 +1,27 @@
+- // MIR for `non_freeze` before GVN
++ // MIR for `non_freeze` after GVN
+  
+  fn non_freeze(_1: T) -> () {
+      let mut _0: ();
+      let mut _2: T;
+      let mut _3: &T;
+  
+      bb0: {
+          _2 = _1;
+          _3 = &_1;
+          _0 = opaque::<&T>(_3) -> [return: bb1, unwind continue];
+      }
+  
+      bb1: {
+          _0 = opaque::<T>(_2) -> [return: bb2, unwind continue];
+      }
+  
+      bb2: {
+          _0 = opaque::<T>((*_3)) -> [return: bb3, unwind continue];
+      }
+  
+      bb3: {
+          return;
+      }
+  }
+  

tests/mir-opt/gvn.rs

@@ -720,6 +720,65 @@ fn wide_ptr_integer() {
     opaque(a >= b);
 }
 
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn borrowed(x: u32) {
+    // CHECK-LABEL: fn borrowed(
+    // CHECK: bb0: {
+    // CHECK-NEXT: _2 = _1;
+    // CHECK-NEXT: _3 = &_1;
+    // CHECK-NEXT: _0 = opaque::<&u32>(_3)
+    // CHECK: bb1: {
+    // CHECK-NEXT: _0 = opaque::<u32>(_2)
+    // CHECK: bb2: {
+    // CHECK-NEXT: _0 = opaque::<u32>((*_3))
+    mir!(
+        {
+            let a = x;
+            let r1 = &x;
+            Call(RET = opaque(r1), ReturnTo(next), UnwindContinue())
+        }
+        next = {
+            Call(RET = opaque(a), ReturnTo(deref), UnwindContinue())
+        }
+        deref = {
+            Call(RET = opaque(*r1), ReturnTo(ret), UnwindContinue())
+        }
+        ret = {
+            Return()
+        }
+    )
+}
+
+/// Generic type `T` is not known to be `Freeze`, so shared borrows may be mutable.
+#[custom_mir(dialect = "analysis", phase = "post-cleanup")]
+fn non_freeze<T: Copy>(x: T) {
+    // CHECK-LABEL: fn non_freeze(
+    // CHECK: bb0: {
+    // CHECK-NEXT: _2 = _1;
+    // CHECK-NEXT: _3 = &_1;
+    // CHECK-NEXT: _0 = opaque::<&T>(_3)
+    // CHECK: bb1: {
+    // CHECK-NEXT: _0 = opaque::<T>(_2)
+    // CHECK: bb2: {
+    // CHECK-NEXT: _0 = opaque::<T>((*_3))
+    mir!(
+        {
+            let a = x;
+            let r1 = &x;
+            Call(RET = opaque(r1), ReturnTo(next), UnwindContinue())
+        }
+        next = {
+            Call(RET = opaque(a), ReturnTo(deref), UnwindContinue())
+        }
+        deref = {
+            Call(RET = opaque(*r1), ReturnTo(ret), UnwindContinue())
+        }
+        ret = {
+            Return()
+        }
+    )
+}
+
 fn main() {
     subexpression_elimination(2, 4, 5);
     wrap_unwrap(5);
@@ -742,6 +801,8 @@ fn main() {
     constant_index_overflow(&[5, 3]);
     wide_ptr_provenance();
     wide_ptr_integer();
+    borrowed(5);
+    non_freeze(5);
 }
 
 #[inline(never)]
@@ -773,3 +834,5 @@ fn identity<T>(x: T) -> T {
 // EMIT_MIR gvn.wide_ptr_provenance.GVN.diff
 // EMIT_MIR gvn.wide_ptr_same_provenance.GVN.diff
 // EMIT_MIR gvn.wide_ptr_integer.GVN.diff
+// EMIT_MIR gvn.borrowed.GVN.diff
+// EMIT_MIR gvn.non_freeze.GVN.diff