Auto merge of #147614 - cjgillot:dest-prop-place, r=<try>

Perform DestinationPropagation on places.

Author: rust-bors[bot]

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -20,13 +20,12 @@ pub fn pair_i32_bool(pair: (i32, bool)) -> (i32, bool) {
     pair
 }
 
-// CHECK: define{{.*}}{ i1, i1 } @pair_and_or(i1 noundef zeroext %_1.0, i1 noundef zeroext %_1.1)
+// CHECK: define{{.*}}{ i1, i1 } @pair_and_or(i1 noundef zeroext %0, i1 noundef zeroext %1)
 #[no_mangle]
 pub fn pair_and_or((a, b): (bool, bool)) -> (bool, bool) {
     // Make sure it can operate directly on the unpacked args
-    // (but it might not be using simple and/or instructions)
-    // CHECK-DAG: %_1.0
-    // CHECK-DAG: %_1.1
+    // CHECK: or i1 %0, %1
+    // CHECK: and i1 %0, %1
     (a && b, a || b)
 }
 

tests/codegen-llvm/scalar-pair-bool.rs

@@ -3,7 +3,7 @@
 
   fn remap_debuginfo_locals(_1: bool, _2: &bool) -> &bool {
 -     debug c => _3;
-+     debug c => _2;
++     debug c => _0;
       let mut _0: &bool;
       let mut _3: &bool;
       let mut _4: bool;
@@ -14,10 +14,10 @@
 -         _4 = copy _1;
 -         _3 = copy _2;
 -         switchInt(copy _4) -> [1: bb1, otherwise: bb2];
-+         // DBG: _2 = &_1;
-+         nop;
++         // DBG: _0 = &_1;
 +         nop;
 +         nop;
++         _0 = copy _2;
 +         switchInt(copy _1) -> [1: bb1, otherwise: bb2];
       }
 
@@ -29,7 +29,7 @@
 -         StorageDead(_4);
 -         _0 = copy _3;
 +         nop;
-+         _0 = copy _2;
++         nop;
           return;
       }
   }

tests/mir-opt/debuginfo/dest_prop.remap_debuginfo_locals.DestinationPropagation.diff

@@ -8,20 +8,20 @@
       let mut _3: u8;
 
       bb0: {
-          StorageLive(_2);
--         StorageLive(_3);
--         _3 = copy _1;
--         _2 = dummy(move _3) -> [return: bb1, unwind unreachable];
-+         nop;
+-         StorageLive(_2);
 +         nop;
-+         _2 = dummy(move _1) -> [return: bb1, unwind unreachable];
+          StorageLive(_3);
+          _3 = copy _1;
+-         _2 = dummy(move _3) -> [return: bb1, unwind unreachable];
++         _1 = dummy(move _3) -> [return: bb1, unwind unreachable];
       }
 
       bb1: {
--         StorageDead(_3);
+          StorageDead(_3);
+-         _1 = move _2;
+-         StorageDead(_2);
++         nop;
 +         nop;
-          _1 = move _2;
-          StorageDead(_2);
           _0 = const ();
           return;
       }

tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-abort.diff

@@ -8,20 +8,20 @@
       let mut _3: u8;
 
       bb0: {
-          StorageLive(_2);
--         StorageLive(_3);
--         _3 = copy _1;
--         _2 = dummy(move _3) -> [return: bb1, unwind continue];
-+         nop;
+-         StorageLive(_2);
 +         nop;
-+         _2 = dummy(move _1) -> [return: bb1, unwind continue];
+          StorageLive(_3);
+          _3 = copy _1;
+-         _2 = dummy(move _3) -> [return: bb1, unwind continue];
++         _1 = dummy(move _3) -> [return: bb1, unwind continue];
       }
 
       bb1: {
--         StorageDead(_3);
+          StorageDead(_3);
+-         _1 = move _2;
+-         StorageDead(_2);
++         nop;
 +         nop;
-          _1 = move _2;
-          StorageDead(_2);
           _0 = const ();
           return;
       }

tests/mir-opt/dest-prop/copy_propagation_arg.foo.DestinationPropagation.panic-unwind.diff

@@ -10,8 +10,9 @@ fn dummy(x: u8) -> u8 {
 fn foo(mut x: u8) {
     // CHECK-LABEL: fn foo(
     // CHECK: debug x => [[x:_.*]];
-    // CHECK: dummy(move [[x]])
-    // CHECK: [[x]] = move {{_.*}};
+    // CHECK: [[tmp:_.*]] = copy [[x]];
+    // CHECK: [[x]] = dummy(move [[tmp]])
+
     // calling `dummy` to make a use of `x` that copyprop cannot eliminate
     x = dummy(x); // this will assign a local to `x`
 }

tests/mir-opt/dest-prop/copy_propagation_arg.rs

@@ -8,23 +8,25 @@
       let _5: ();
       let mut _6: i32;
       scope 1 {
-          debug x => _1;
+-         debug x => _1;
++         debug x => _4;
           let _2: i32;
           scope 2 {
 -             debug y => _2;
-+             debug y => _1;
++             debug y => _4;
               let _3: i32;
               scope 3 {
 -                 debug z => _3;
-+                 debug z => _1;
++                 debug z => _4;
               }
           }
       }
 
       bb0: {
 -         StorageLive(_1);
+-         _1 = val() -> [return: bb1, unwind unreachable];
 +         nop;
-          _1 = val() -> [return: bb1, unwind unreachable];
++         _4 = val() -> [return: bb1, unwind unreachable];
       }
 
       bb1: {
@@ -50,7 +52,7 @@
 -         _5 = std::mem::drop::<i32>(move _6) -> [return: bb2, unwind unreachable];
 +         nop;
 +         nop;
-+         _5 = std::mem::drop::<i32>(move _1) -> [return: bb2, unwind unreachable];
++         _5 = std::mem::drop::<i32>(move _4) -> [return: bb2, unwind unreachable];
       }
 
       bb2: {

tests/mir-opt/dest-prop/cycle.main.DestinationPropagation.panic-abort.diff

@@ -8,23 +8,25 @@
       let _5: ();
       let mut _6: i32;
       scope 1 {
-          debug x => _1;
+-         debug x => _1;
++         debug x => _4;
           let _2: i32;
           scope 2 {
 -             debug y => _2;
-+             debug y => _1;
++             debug y => _4;
               let _3: i32;
               scope 3 {
 -                 debug z => _3;
-+                 debug z => _1;
++                 debug z => _4;
               }
           }
       }
 
       bb0: {
 -         StorageLive(_1);
+-         _1 = val() -> [return: bb1, unwind continue];
 +         nop;
-          _1 = val() -> [return: bb1, unwind continue];
++         _4 = val() -> [return: bb1, unwind continue];
       }
 
       bb1: {
@@ -50,7 +52,7 @@
 -         _5 = std::mem::drop::<i32>(move _6) -> [return: bb2, unwind continue];
 +         nop;
 +         nop;
-+         _5 = std::mem::drop::<i32>(move _1) -> [return: bb2, unwind continue];
++         _5 = std::mem::drop::<i32>(move _4) -> [return: bb2, unwind continue];
       }
 
       bb2: {

tests/mir-opt/dest-prop/cycle.main.DestinationPropagation.panic-unwind.diff

@@ -11,12 +11,12 @@ fn f(_1: usize) -> usize {
     }
 
     bb0: {
-        nop;
+        StorageLive(_2);
         _2 = copy _1;
         _1 = const 5_usize;
         nop;
+        _1 = copy _2;
         nop;
-        _1 = move _2;
         nop;
         nop;
         nop;
@@ -25,7 +25,7 @@ fn f(_1: usize) -> usize {
 
     bb1: {
         nop;
-        nop;
+        StorageDead(_2);
         return;
     }
 }

tests/mir-opt/dest-prop/dead_stores_79191.f.DestinationPropagation.after.panic-abort.mir

@@ -11,12 +11,12 @@ fn f(_1: usize) -> usize {
     }
 
     bb0: {
-        nop;
+        StorageLive(_2);
         _2 = copy _1;
         _1 = const 5_usize;
         nop;
+        _1 = copy _2;
         nop;
-        _1 = move _2;
         nop;
         nop;
         nop;
@@ -25,7 +25,7 @@ fn f(_1: usize) -> usize {
 
     bb1: {
         nop;
-        nop;
+        StorageDead(_2);
         return;
     }
 }