Simplify assignment.

Author: cjgillot

compiler/rustc_mir_transform/src/coroutine.rs

@@ -512,17 +512,15 @@ fn make_coroutine_state_argument_pinned<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body
     SelfArgVisitor::new(tcx, tcx.mk_place_deref(unpinned_local.into())).visit_body(body);
 
     let source_info = SourceInfo::outermost(body.span);
+    let pin_field = tcx.mk_place_field(SELF_ARG.into(), FieldIdx::ZERO, ref_coroutine_ty);
+
     body.basic_blocks_mut()[START_BLOCK].statements.insert(
         0,
         Statement::new(
             source_info,
             StatementKind::Assign(Box::new((
                 unpinned_local.into(),
-                Rvalue::CopyForDeref(tcx.mk_place_field(
-                    SELF_ARG.into(),
-                    FieldIdx::ZERO,
-                    ref_coroutine_ty,
-                )),
+                Rvalue::Use(Operand::Copy(pin_field)),
             ))),
         ),
     );

tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-abort.mir

@@ -27,7 +27,7 @@ fn a::{closure#0}(_1: Pin<&mut {async fn body of a<T>()}>, _2: &mut Context<'_>)
     }
 
     bb0: {
-        _20 = deref_copy (_1.0: &mut {async fn body of a<T>()});
+        _20 = copy (_1.0: &mut {async fn body of a<T>()});
         _19 = discriminant((*_20));
         switchInt(move _19) -> [0: bb9, 3: bb12, 4: bb13, otherwise: bb14];
     }

tests/mir-opt/async_drop_live_dead.a-{closure#0}.coroutine_drop_async.0.panic-unwind.mir

@@ -27,7 +27,7 @@ fn a::{closure#0}(_1: Pin<&mut {async fn body of a<T>()}>, _2: &mut Context<'_>)
     }
 
     bb0: {
-        _20 = deref_copy (_1.0: &mut {async fn body of a<T>()});
+        _20 = copy (_1.0: &mut {async fn body of a<T>()});
         _19 = discriminant((*_20));
         switchInt(move _19) -> [0: bb12, 2: bb18, 3: bb16, 4: bb17, otherwise: bb19];
     }

tests/mir-opt/building/async_await.a-{closure#0}.coroutine_resume.0.mir

@@ -17,7 +17,7 @@ fn a::{closure#0}(_1: Pin<&mut {async fn body of a()}>, _2: &mut Context<'_>) ->
     let mut _5: &mut {async fn body of a()};
 
     bb0: {
-        _5 = deref_copy (_1.0: &mut {async fn body of a()});
+        _5 = copy (_1.0: &mut {async fn body of a()});
         _4 = discriminant((*_5));
         switchInt(move _4) -> [0: bb1, 1: bb4, otherwise: bb5];
     }

tests/mir-opt/building/async_await.b-{closure#0}.coroutine_resume.0.mir

@@ -103,7 +103,7 @@ fn b::{closure#0}(_1: Pin<&mut {async fn body of b()}>, _2: &mut Context<'_>) ->
     }
 
     bb0: {
-        _39 = deref_copy (_1.0: &mut {async fn body of b()});
+        _39 = copy (_1.0: &mut {async fn body of b()});
         _38 = discriminant((*_39));
         switchInt(move _38) -> [0: bb1, 1: bb29, 3: bb27, 4: bb28, otherwise: bb8];
     }

tests/mir-opt/building/coroutine.main-{closure#0}.StateTransform.after.mir

@@ -43,7 +43,7 @@ fn main::{closure#0}(_1: Pin<&mut {coroutine@$DIR/coroutine.rs:18:5: 18:18}>, _2
     let mut _18: &mut {coroutine@$DIR/coroutine.rs:18:5: 18:18};
 
     bb0: {
-        _18 = deref_copy (_1.0: &mut {coroutine@$DIR/coroutine.rs:18:5: 18:18});
+        _18 = copy (_1.0: &mut {coroutine@$DIR/coroutine.rs:18:5: 18:18});
         _17 = discriminant((*_18));
         switchInt(move _17) -> [0: bb1, 1: bb19, 3: bb17, 4: bb18, otherwise: bb20];
     }

tests/mir-opt/building/coroutine.main-{closure#1}.StateTransform.after.mir

@@ -43,7 +43,7 @@ fn main::{closure#1}(_1: Pin<&mut {coroutine@$DIR/coroutine.rs:25:5: 25:18}>, _2
     let mut _18: &mut {coroutine@$DIR/coroutine.rs:25:5: 25:18};
 
     bb0: {
-        _18 = deref_copy (_1.0: &mut {coroutine@$DIR/coroutine.rs:25:5: 25:18});
+        _18 = copy (_1.0: &mut {coroutine@$DIR/coroutine.rs:25:5: 25:18});
         _17 = discriminant((*_18));
         switchInt(move _17) -> [0: bb1, 1: bb19, 3: bb17, 4: bb18, otherwise: bb20];
     }

tests/mir-opt/coroutine_tiny.main-{closure#0}.coroutine_resume.0.mir

@@ -38,7 +38,7 @@ fn main::{closure#0}(_1: Pin<&mut {coroutine@$DIR/coroutine_tiny.rs:21:5: 21:13}
     }
 
     bb0: {
-        _11 = deref_copy (_1.0: &mut {coroutine@$DIR/coroutine_tiny.rs:21:5: 21:13});
+        _11 = copy (_1.0: &mut {coroutine@$DIR/coroutine_tiny.rs:21:5: 21:13});
         _10 = discriminant((*_11));
         switchInt(move _10) -> [0: bb1, 3: bb5, otherwise: bb6];
     }

tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff

@@ -125,7 +125,7 @@
 +         StorageLive(_30);
 +         StorageLive(_31);
 +         StorageLive(_32);
-+         _32 = deref_copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
++         _32 = copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
 +         _31 = discriminant((*_32));
 +         switchInt(move _31) -> [0: bb3, 1: bb10, 3: bb9, otherwise: bb5];
       }

tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff

@@ -125,7 +125,7 @@
 +         StorageLive(_30);
 +         StorageLive(_31);
 +         StorageLive(_32);
-+         _32 = deref_copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
++         _32 = copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
 +         _31 = discriminant((*_32));
 +         switchInt(move _31) -> [0: bb5, 1: bb15, 2: bb14, 3: bb13, otherwise: bb7];
       }