Rollup merge of #82684 - tmiasko:dest-prop, r=jonas-schievink

Disable destination propagation on all mir-opt-levels The new `// compile-flags: -Zunsound-mir-opts` are inserted without an extra newline to avoid introducing a large mir-opt diff.
rust-lang · Mar 8, 2021 · dd7a606 · dd7a606
2 parents 9c31057 + 6f49aad
commit dd7a606
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Showing 15 changed files with 260 additions and 147 deletions.
diff --git a/compiler/rustc_mir/src/transform/dest_prop.rs b/compiler/rustc_mir/src/transform/dest_prop.rs
@@ -127,6 +127,11 @@ pub struct DestinationPropagation;
 
 impl<'tcx> MirPass<'tcx> for DestinationPropagation {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+        //  FIXME(#79191, #82678)
+        if !tcx.sess.opts.debugging_opts.unsound_mir_opts {
+            return;
+        }
+
         // Only run at mir-opt-level=3 or higher for now (we don't fix up debuginfo and remove
         // storage statements at the moment).
         if tcx.sess.mir_opt_level() < 3 {

diff --git a/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff b/src/test/mir-opt/deduplicate_blocks.is_line_doc_comment_2.DeduplicateBlocks.diff
@@ -5,22 +5,26 @@
       debug s => _1;                       // in scope 0 at $DIR/deduplicate_blocks.rs:2:36: 2:37
       let mut _0: bool;                    // return place in scope 0 at $DIR/deduplicate_blocks.rs:2:48: 2:52
       let mut _2: &[u8];                   // in scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:23
-      let mut _3: usize;                   // in scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
-      let mut _4: bool;                    // in scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
-      let mut _5: usize;                   // in scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
-      let mut _6: bool;                    // in scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
+      let mut _3: &str;                    // in scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:12
+      let mut _4: usize;                   // in scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
+      let mut _5: bool;                    // in scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
+      let mut _6: usize;                   // in scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
+      let mut _7: bool;                    // in scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
       scope 1 (inlined core::str::<impl str>::as_bytes) { // at $DIR/deduplicate_blocks.rs:3:11: 3:23
-          debug self => _7;                // in scope 1 at $DIR/deduplicate_blocks.rs:3:11: 3:23
-          let mut _7: &str;                // in scope 1 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+          debug self => _3;                // in scope 1 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+          let mut _8: &str;                // in scope 1 at $DIR/deduplicate_blocks.rs:3:11: 3:23
           scope 2 {
           }
       }
 
       bb0: {
           StorageLive(_2);                 // scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:23
-          _7 = _1;                         // scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:12
--         _2 = transmute::<&str, &[u8]>(move _7) -> bb14; // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
-+         _2 = transmute::<&str, &[u8]>(move _7) -> bb12; // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+          StorageLive(_3);                 // scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:12
+          _3 = _1;                         // scope 0 at $DIR/deduplicate_blocks.rs:3:11: 3:12
+          StorageLive(_8);                 // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+          _8 = _3;                         // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+-         _2 = transmute::<&str, &[u8]>(move _8) -> bb14; // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
++         _2 = transmute::<&str, &[u8]>(move _8) -> bb12; // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
                                            // mir::Constant
                                            // + span: $DIR/deduplicate_blocks.rs:3:11: 3:23
                                            // + literal: Const { ty: unsafe extern "rust-intrinsic" fn(&str) -> &[u8] {std::intrinsics::transmute::<&str, &[u8]>}, val: Value(Scalar(<ZST>)) }
@@ -44,9 +48,9 @@
       }
 
       bb5: {
-          _3 = Len((*_2));                 // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
-          _4 = Ge(move _3, const 3_usize); // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
-          switchInt(move _4) -> [false: bb9, otherwise: bb6]; // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
+          _4 = Len((*_2));                 // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
+          _5 = Ge(move _4, const 3_usize); // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
+          switchInt(move _5) -> [false: bb9, otherwise: bb6]; // scope 0 at $DIR/deduplicate_blocks.rs:5:9: 5:31
       }
 
       bb6: {
@@ -93,9 +97,11 @@
 
 -     bb14: {
 +     bb12: {
-          _5 = Len((*_2));                 // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
-          _6 = Ge(move _5, const 4_usize); // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
-          switchInt(move _6) -> [false: bb5, otherwise: bb1]; // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
+          StorageDead(_8);                 // scope 2 at $DIR/deduplicate_blocks.rs:3:11: 3:23
+          StorageDead(_3);                 // scope 0 at $DIR/deduplicate_blocks.rs:3:22: 3:23
+          _6 = Len((*_2));                 // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
+          _7 = Ge(move _6, const 4_usize); // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
+          switchInt(move _7) -> [false: bb5, otherwise: bb1]; // scope 0 at $DIR/deduplicate_blocks.rs:4:9: 4:37
       }
   }
 
diff --git a/src/test/mir-opt/dest-prop/branch.rs b/src/test/mir-opt/dest-prop/branch.rs
@@ -1,5 +1,5 @@
 //! Tests that assignment in both branches of an `if` are eliminated.
-
+// compile-flags: -Zunsound-mir-opts
 fn val() -> i32 {
     1
 }

diff --git a/src/test/mir-opt/dest-prop/copy_propagation_arg.rs b/src/test/mir-opt/dest-prop/copy_propagation_arg.rs
@@ -1,6 +1,6 @@
 // Check that DestinationPropagation does not propagate an assignment to a function argument
 // (doing so can break usages of the original argument value)
-
+// compile-flags: -Zunsound-mir-opts
 fn dummy(x: u8) -> u8 {
     x
 }

diff --git a/src/test/mir-opt/dest-prop/cycle.rs b/src/test/mir-opt/dest-prop/cycle.rs
@@ -1,5 +1,5 @@
 //! Tests that cyclic assignments don't hang DestinationPropagation, and result in reasonable code.
-
+// compile-flags: -Zunsound-mir-opts
 fn val() -> i32 {
     1
 }

diff --git a/src/test/mir-opt/dest-prop/simple.rs b/src/test/mir-opt/dest-prop/simple.rs
@@ -1,5 +1,5 @@
 //! Copy of `nrvo-simple.rs`, to ensure that full dest-prop handles it too.
-
+// compile-flags: -Zunsound-mir-opts
 // EMIT_MIR simple.nrvo.DestinationPropagation.diff
 fn nrvo(init: fn(&mut [u8; 1024])) -> [u8; 1024] {
     let mut buf = [0; 1024];

diff --git a/src/test/mir-opt/dest-prop/union.rs b/src/test/mir-opt/dest-prop/union.rs
@@ -1,5 +1,5 @@
 //! Tests that projections through unions cancel `DestinationPropagation`.
-
+// compile-flags: -Zunsound-mir-opts
 fn val() -> u32 {
     1
 }

diff --git a/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir b/src/test/mir-opt/inline/inline_closure_captures.foo.Inline.after.mir
@@ -17,7 +17,8 @@ fn foo(_1: T, _2: i32) -> (i32, T) {
             debug _q => _9;              // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
             debug q => (*((*_6).0: &i32)); // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
             debug t => (*((*_6).1: &T)); // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
-            let mut _10: T;              // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+            let mut _10: i32;            // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+            let mut _11: T;              // in scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
         }
     }
 
@@ -39,10 +40,13 @@ fn foo(_1: T, _2: i32) -> (i32, T) {
         (_7.0: i32) = move _8;           // scope 1 at $DIR/inline-closure-captures.rs:12:5: 12:9
         StorageLive(_9);                 // scope 1 at $DIR/inline-closure-captures.rs:12:5: 12:9
         _9 = move (_7.0: i32);           // scope 1 at $DIR/inline-closure-captures.rs:12:5: 12:9
-        (_0.0: i32) = (*((*_6).0: &i32)); // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
         StorageLive(_10);                // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
-        _10 = (*((*_6).1: &T));          // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
-        (_0.1: T) = move _10;            // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        _10 = (*((*_6).0: &i32));        // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        StorageLive(_11);                // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        _11 = (*((*_6).1: &T));          // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        (_0.0: i32) = move _10;          // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        (_0.1: T) = move _11;            // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
+        StorageDead(_11);                // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
         StorageDead(_10);                // scope 2 at $DIR/inline-closure-captures.rs:12:5: 12:9
         StorageDead(_9);                 // scope 1 at $DIR/inline-closure-captures.rs:12:5: 12:9
         StorageDead(_8);                 // scope 1 at $DIR/inline-closure-captures.rs:12:8: 12:9

diff --git a/src/test/mir-opt/inline/inline_diverging.h.Inline.diff b/src/test/mir-opt/inline/inline_diverging.h.Inline.diff
@@ -5,18 +5,20 @@
       let mut _0: ();                      // return place in scope 0 at $DIR/inline-diverging.rs:21:12: 21:12
       let _1: (!, !);                      // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
 +     let mut _2: fn() -> ! {sleep};       // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
-+     let mut _7: ();                      // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
-+     let mut _8: ();                      // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
++     let mut _9: ();                      // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
++     let mut _10: ();                     // in scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
 +     scope 1 (inlined call_twice::<!, fn() -> ! {sleep}>) { // at $DIR/inline-diverging.rs:22:5: 22:22
 +         debug f => _2;                   // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         let _3: !;                       // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         let mut _4: &fn() -> ! {sleep};  // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
-+         let mut _5: &fn() -> ! {sleep};  // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
-+         let mut _6: !;                   // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
++         let mut _6: &fn() -> ! {sleep};  // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
++         let mut _7: !;                   // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
++         let mut _8: !;                   // in scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         scope 2 {
 +             debug a => _3;               // in scope 2 at $DIR/inline-diverging.rs:22:5: 22:22
++             let _5: !;                   // in scope 2 at $DIR/inline-diverging.rs:22:5: 22:22
 +             scope 3 {
-+                 debug b => _6;           // in scope 3 at $DIR/inline-diverging.rs:22:5: 22:22
++                 debug b => _5;           // in scope 3 at $DIR/inline-diverging.rs:22:5: 22:22
 +             }
 +             scope 6 (inlined <fn() -> ! {sleep} as Fn<()>>::call - shim(fn() -> ! {sleep})) { // at $DIR/inline-diverging.rs:22:5: 22:22
 +                 scope 7 (inlined sleep) { // at $DIR/inline-diverging.rs:22:5: 22:22
@@ -40,12 +42,11 @@
 -                                          // mir::Constant
                                            // + span: $DIR/inline-diverging.rs:22:16: 22:21
                                            // + literal: Const { ty: fn() -> ! {sleep}, val: Value(Scalar(<ZST>)) }
-+         StorageLive(_6);                 // scope 0 at $DIR/inline-diverging.rs:22:5: 22:22
 +         StorageLive(_3);                 // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         StorageLive(_4);                 // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         _4 = &_2;                        // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
-+         StorageLive(_7);                 // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
-+         _7 = const ();                   // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
++         StorageLive(_9);                 // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
++         _9 = const ();                   // scope 1 at $DIR/inline-diverging.rs:22:5: 22:22
 +         goto -> bb1;                     // scope 4 at $DIR/inline-diverging.rs:22:5: 22:22
       }
 

diff --git a/src/test/mir-opt/inline/inline_generator.main.Inline.diff b/src/test/mir-opt/inline/inline_generator.main.Inline.diff
@@ -24,9 +24,12 @@
 +         }
 +     }
 +     scope 6 (inlined g::{closure#0}) {   // at $DIR/inline-generator.rs:9:14: 9:46
-+         debug a => _8;                   // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
-+         let mut _8: bool;                // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
-+         let mut _9: u32;                 // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         debug a => _11;                  // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _8: i32;                 // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _9: bool;                // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _10: bool;               // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let _11: bool;                   // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         let mut _12: u32;                // in scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +     }
 
       bb0: {
@@ -65,16 +68,18 @@
 -                                          // + literal: Const { ty: for<'r> fn(std::pin::Pin<&'r mut impl std::ops::Generator<bool>>, bool) -> std::ops::GeneratorState<<impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Yield, <impl std::ops::Generator<bool> as std::ops::Generator<bool>>::Return> {<impl std::ops::Generator<bool> as std::ops::Generator<bool>>::resume}, val: Value(Scalar(<ZST>)) }
 +         StorageLive(_7);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
 +         _7 = const false;                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
-+         StorageLive(_8);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
-+         StorageLive(_9);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
-+         _9 = discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))); // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
-+         switchInt(move _9) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_10);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_11);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_12);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         _12 = discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))); // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         switchInt(move _12) -> [0_u32: bb3, 1_u32: bb8, 3_u32: bb7, otherwise: bb9]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
       }
 
 -     bb3: {
 +     bb1: {
-+         StorageDead(_9);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
-+         StorageDead(_8);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageDead(_12);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageDead(_11);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageDead(_10);                // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
 +         StorageDead(_7);                 // scope 0 at $DIR/inline-generator.rs:9:14: 9:46
           StorageDead(_2);                 // scope 0 at $DIR/inline-generator.rs:9:45: 9:46
           StorageDead(_4);                 // scope 0 at $DIR/inline-generator.rs:9:46: 9:47
@@ -89,28 +94,36 @@
 +     }
 + 
 +     bb3: {
-+         _8 = move _7;                    // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
-+         switchInt(move _8) -> [false: bb5, otherwise: bb4]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         _11 = move _7;                   // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_8);                 // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_9);                 // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         _9 = _11;                        // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         switchInt(move _9) -> [false: bb5, otherwise: bb4]; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +     }
 + 
 +     bb4: {
-+         ((_1 as Yielded).0: i32) = const 7_i32; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         _8 = const 7_i32;                // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         goto -> bb6;                     // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +     }
 + 
 +     bb5: {
-+         ((_1 as Yielded).0: i32) = const 13_i32; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         _8 = const 13_i32;               // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         goto -> bb6;                     // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +     }
 + 
 +     bb6: {
++         StorageDead(_9);                 // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         ((_1 as Yielded).0: i32) = move _8; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         discriminant(_1) = 0;            // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))) = 3; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:11: 15:39
 +     }
 + 
 +     bb7: {
-+         ((_1 as Complete).0: bool) = move _7; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageLive(_8);                 // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         _10 = move _7;                   // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         StorageDead(_8);                 // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
++         ((_1 as Complete).0: bool) = move _10; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         discriminant(_1) = 1;            // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         discriminant((*(_2.0: &mut [generator@$DIR/inline-generator.rs:15:5: 15:41 {bool, i32}]))) = 1; // scope 6 at $DIR/inline-generator.rs:9:14: 9:46
 +         goto -> bb1;                     // scope 0 at $DIR/inline-generator.rs:15:41: 15:41