Rollup merge of #77066 - jonas-schievink:dest-prop-borrow, r=oli-obk

Fix dest prop miscompilation around references

Closes #77002

Author: jonas-schievink

compiler/rustc_mir/src/transform/dest_prop.rs

@@ -905,7 +905,7 @@ impl<'a, 'tcx> Visitor<'tcx> for FindAssignments<'a, 'tcx> {
             // FIXME: This can be smarter and take `StorageDead` into account (which
             // invalidates borrows).
             if self.ever_borrowed_locals.contains(dest.local)
-                && self.ever_borrowed_locals.contains(src.local)
+                || self.ever_borrowed_locals.contains(src.local)
             {
                 return;
             }

src/test/mir-opt/const_allocation3.main.ConstProp.after.32bit.mir

@@ -24,10 +24,10 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 4, align: 4) {
-    ╾─alloc3──╼                                     │ ╾──╼
+    ╾─alloc9──╼                                     │ ╾──╼
 }
 
-alloc3 (size: 168, align: 1) {
+alloc9 (size: 168, align: 1) {
     0x00 │ ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab │ ................
     0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾─alloc4──╼ │ ............╾──╼
     0x20 │ 01 ef cd ab 00 00 00 00 00 00 00 00 00 00 00 00 │ ................

src/test/mir-opt/const_allocation3.main.ConstProp.after.64bit.mir

@@ -24,10 +24,10 @@ fn main() -> () {
 }
 
 alloc0 (static: FOO, size: 8, align: 8) {
-    ╾───────alloc3────────╼                         │ ╾──────╼
+    ╾───────alloc9────────╼                         │ ╾──────╼
 }
 
-alloc3 (size: 180, align: 1) {
+alloc9 (size: 180, align: 1) {
     0x00 │ ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab │ ................
     0x10 │ ab ab ab ab ab ab ab ab ab ab ab ab ╾──alloc4── │ ............╾───
     0x20 │ ──────────╼ 01 ef cd ab 00 00 00 00 00 00 00 00 │ ───╼............

src/test/mir-opt/dest-prop/simple.nrvo.DestinationPropagation.diff

@@ -10,22 +10,18 @@
       let mut _5: &mut [u8; 1024];         // in scope 0 at $DIR/simple.rs:6:10: 6:18
       let mut _6: &mut [u8; 1024];         // in scope 0 at $DIR/simple.rs:6:10: 6:18
       scope 1 {
--         debug buf => _2;                 // in scope 1 at $DIR/simple.rs:5:9: 5:16
-+         debug buf => _0;                 // in scope 1 at $DIR/simple.rs:5:9: 5:16
+          debug buf => _2;                 // in scope 1 at $DIR/simple.rs:5:9: 5:16
       }
 
       bb0: {
--         StorageLive(_2);                 // scope 0 at $DIR/simple.rs:5:9: 5:16
--         _2 = [const 0_u8; 1024];         // scope 0 at $DIR/simple.rs:5:19: 5:28
-+         nop;                             // scope 0 at $DIR/simple.rs:5:9: 5:16
-+         _0 = [const 0_u8; 1024];         // scope 0 at $DIR/simple.rs:5:19: 5:28
+          StorageLive(_2);                 // scope 0 at $DIR/simple.rs:5:9: 5:16
+          _2 = [const 0_u8; 1024];         // scope 0 at $DIR/simple.rs:5:19: 5:28
           StorageLive(_3);                 // scope 1 at $DIR/simple.rs:6:5: 6:19
           StorageLive(_4);                 // scope 1 at $DIR/simple.rs:6:5: 6:9
           _4 = _1;                         // scope 1 at $DIR/simple.rs:6:5: 6:9
           StorageLive(_5);                 // scope 1 at $DIR/simple.rs:6:10: 6:18
           StorageLive(_6);                 // scope 1 at $DIR/simple.rs:6:10: 6:18
--         _6 = &mut _2;                    // scope 1 at $DIR/simple.rs:6:10: 6:18
-+         _6 = &mut _0;                    // scope 1 at $DIR/simple.rs:6:10: 6:18
+          _6 = &mut _2;                    // scope 1 at $DIR/simple.rs:6:10: 6:18
           _5 = &mut (*_6);                 // scope 1 at $DIR/simple.rs:6:10: 6:18
           _3 = move _4(move _5) -> bb1;    // scope 1 at $DIR/simple.rs:6:5: 6:19
       }
@@ -35,10 +31,8 @@
           StorageDead(_4);                 // scope 1 at $DIR/simple.rs:6:18: 6:19
           StorageDead(_6);                 // scope 1 at $DIR/simple.rs:6:19: 6:20
           StorageDead(_3);                 // scope 1 at $DIR/simple.rs:6:19: 6:20
--         _0 = _2;                         // scope 1 at $DIR/simple.rs:7:5: 7:8
--         StorageDead(_2);                 // scope 0 at $DIR/simple.rs:8:1: 8:2
-+         nop;                             // scope 1 at $DIR/simple.rs:7:5: 7:8
-+         nop;                             // scope 0 at $DIR/simple.rs:8:1: 8:2
+          _0 = _2;                         // scope 1 at $DIR/simple.rs:7:5: 7:8
+          StorageDead(_2);                 // scope 0 at $DIR/simple.rs:8:1: 8:2
           return;                          // scope 0 at $DIR/simple.rs:8:2: 8:2
       }
   }