Auto merge of #132527 - DianQK:gvn-stmt-iter, r=oli-obk

gvn: Invalid dereferences for all non-local mutations

Fixes #132353.

This PR removes the computation value by traversing SSA locals through `for_each_assignment_mut`.

Because the `for_each_assignment_mut` traversal skips statements which have side effects, such as dereference assignments, the computation may be unsound. Instead of `for_each_assignment_mut`, we compute values by traversing in reverse postorder.

Because we compute and use the symbolic representation of values on the fly, I invalidate all old values when encountering a dereference assignment. The current approach does not prevent the optimization of a clone to a copy.

In the future, we may add an alias model, or dominance information for dereference assignments, or SSA form to help GVN.

r? cjgillot

cc `@jieyouxu` #132356
cc `@RalfJung` #133474

Author: bors

compiler/rustc_data_structures/src/fx.rs

@@ -9,6 +9,8 @@ pub type FxIndexSet<V> = indexmap::IndexSet<V, BuildHasherDefault<FxHasher>>;
 pub type IndexEntry<'a, K, V> = indexmap::map::Entry<'a, K, V>;
 pub type IndexOccupiedEntry<'a, K, V> = indexmap::map::OccupiedEntry<'a, K, V>;
 
+pub use indexmap::set::MutableValues;
+
 #[macro_export]
 macro_rules! define_id_collections {
     ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {

compiler/rustc_mir_transform/src/gvn.rs

@@ -32,12 +32,6 @@ pub(super) struct SsaLocals {
     borrowed_locals: DenseBitSet<Local>,
 }
 
-pub(super) enum AssignedValue<'a, 'tcx> {
-    Arg,
-    Rvalue(&'a mut Rvalue<'tcx>),
-    Terminator,
-}
-
 impl SsaLocals {
     pub(super) fn new<'tcx>(
         tcx: TyCtxt<'tcx>,
@@ -152,38 +146,6 @@ impl SsaLocals {
         })
     }
 
-    pub(super) fn for_each_assignment_mut<'tcx>(
-        &self,
-        basic_blocks: &mut IndexSlice<BasicBlock, BasicBlockData<'tcx>>,
-        mut f: impl FnMut(Local, AssignedValue<'_, 'tcx>, Location),
-    ) {
-        for &local in &self.assignment_order {
-            match self.assignments[local] {
-                Set1::One(DefLocation::Argument) => f(
-                    local,
-                    AssignedValue::Arg,
-                    Location { block: START_BLOCK, statement_index: 0 },
-                ),
-                Set1::One(DefLocation::Assignment(loc)) => {
-                    let bb = &mut basic_blocks[loc.block];
-                    // `loc` must point to a direct assignment to `local`.
-                    let stmt = &mut bb.statements[loc.statement_index];
-                    let StatementKind::Assign(box (target, ref mut rvalue)) = stmt.kind else {
-                        bug!()
-                    };
-                    assert_eq!(target.as_local(), Some(local));
-                    f(local, AssignedValue::Rvalue(rvalue), loc)
-                }
-                Set1::One(DefLocation::CallReturn { call, .. }) => {
-                    let bb = &mut basic_blocks[call];
-                    let loc = Location { block: call, statement_index: bb.statements.len() };
-                    f(local, AssignedValue::Terminator, loc)
-                }
-                _ => {}
-            }
-        }
-    }
-
     /// Compute the equivalence classes for locals, based on copy statements.
     ///
     /// The returned vector maps each local to the one it copies. In the following case:

compiler/rustc_mir_transform/src/ssa.rs

@@ -1,6 +1,4 @@
 //@ revisions: DEBUGINFO NODEBUGINFO
-//@ compile-flags: -Zunsound-mir-opts
-// FIXME: see <https://github.com/rust-lang/rust/issues/132353>
 //@ compile-flags: -Copt-level=3 -Cno-prepopulate-passes
 //@ [DEBUGINFO] compile-flags: -Cdebuginfo=full
 

tests/codegen/clone_as_copy.rs

@@ -16,12 +16,17 @@ use std::ptr::NonNull;
 #[no_mangle]
 pub fn option_nop_match_32(x: Option<u32>) -> Option<u32> {
     // CHECK: start:
-    // TWENTY-NEXT: %[[IS_SOME:.+]] = trunc nuw i32 %0 to i1
-    // TWENTY-NEXT: %[[PAYLOAD:.+]] = select i1 %[[IS_SOME]], i32 %1, i32 undef
-    // CHECK-NEXT: [[REG1:%.*]] = insertvalue { i32, i32 } poison, i32 %0, 0
-    // NINETEEN-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } [[REG1]], i32 %1, 1
-    // TWENTY-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } [[REG1]], i32 %[[PAYLOAD]], 1
-    // CHECK-NEXT: ret { i32, i32 } [[REG2]]
+    // CHECK-NEXT: [[TRUNC:%.*]] = trunc nuw i32 %0 to i1
+
+    // NINETEEN-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i32 %0, i32 0
+    // NINETEEN-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } poison, i32 [[SELECT]], 0
+    // NINETEEN-NEXT: [[REG3:%.*]] = insertvalue { i32, i32 } [[REG2]], i32 %1, 1
+
+    // TWENTY-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i32 %1, i32 undef
+    // TWENTY-NEXT: [[REG2:%.*]] = insertvalue { i32, i32 } poison, i32 %0, 0
+    // TWENTY-NEXT: [[REG3:%.*]] = insertvalue { i32, i32 } [[REG2]], i32 [[SELECT]], 1
+
+    // CHECK-NEXT: ret { i32, i32 } [[REG3]]
     match x {
         Some(x) => Some(x),
         None => None,
@@ -90,12 +95,17 @@ pub fn control_flow_nop_traits_32(x: ControlFlow<i32, u32>) -> ControlFlow<i32,
 #[no_mangle]
 pub fn option_nop_match_64(x: Option<u64>) -> Option<u64> {
     // CHECK: start:
-    // TWENTY-NEXT: %[[TRUNC:[0-9]+]] = trunc nuw i64 %0 to i1
-    // TWENTY-NEXT: %[[SEL:\.[0-9]+]] = select i1 %[[TRUNC]], i64 %1, i64 undef
-    // CHECK-NEXT: [[REG1:%[0-9a-zA-Z_.]+]] = insertvalue { i64, i64 } poison, i64 %0, 0
-    // NINETEEN-NEXT: [[REG2:%[0-9a-zA-Z_.]+]] = insertvalue { i64, i64 } [[REG1]], i64 %1, 1
-    // TWENTY-NEXT: [[REG2:%[0-9a-zA-Z_.]+]] = insertvalue { i64, i64 } [[REG1]], i64 %[[SEL]], 1
-    // CHECK-NEXT: ret { i64, i64 } [[REG2]]
+    // CHECK-NEXT: [[TRUNC:%.*]] = trunc nuw i64 %0 to i1
+
+    // NINETEEN-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i64 %0, i64 0
+    // NINETEEN-NEXT: [[REG2:%.*]] = insertvalue { i64, i64 } poison, i64 [[SELECT]], 0
+    // NINETEEN-NEXT: [[REG3:%.*]] = insertvalue { i64, i64 } [[REG2]], i64 %1, 1
+
+    // TWENTY-NEXT: [[SELECT:%.*]] = select i1 [[TRUNC]], i64 %1, i64 undef
+    // TWENTY-NEXT: [[REG2:%.*]] = insertvalue { i64, i64 } poison, i64 %0, 0
+    // TWENTY-NEXT: [[REG3:%.*]] = insertvalue { i64, i64 } [[REG2]], i64 [[SELECT]], 1
+
+    // CHECK-NEXT: ret { i64, i64 } [[REG3]]
     match x {
         Some(x) => Some(x),
         None => None,
@@ -164,8 +174,8 @@ pub fn control_flow_nop_traits_64(x: ControlFlow<i64, u64>) -> ControlFlow<i64,
 #[no_mangle]
 pub fn result_nop_match_128(x: Result<i128, u128>) -> Result<i128, u128> {
     // CHECK: start:
-    // CHECK-NEXT: getelementptr inbounds {{(nuw )?}}i8
     // CHECK-NEXT: store i128
+    // CHECK-NEXT: getelementptr inbounds {{(nuw )?}}i8
     // CHECK-NEXT: store i128
     // CHECK-NEXT: ret void
     match x {
@@ -189,8 +199,8 @@ pub fn result_nop_traits_128(x: Result<i128, u128>) -> Result<i128, u128> {
 #[no_mangle]
 pub fn control_flow_nop_match_128(x: ControlFlow<i128, u128>) -> ControlFlow<i128, u128> {
     // CHECK: start:
-    // CHECK-NEXT: getelementptr inbounds {{(nuw )?}}i8
     // CHECK-NEXT: store i128
+    // CHECK-NEXT: getelementptr inbounds {{(nuw )?}}i8
     // CHECK-NEXT: store i128
     // CHECK-NEXT: ret void
     match x {

tests/codegen/try_question_mark_nop.rs

@@ -59,109 +59,80 @@ Number of file 0 mappings: 1
 Highest counter ID seen: c0
 
 Function name: issue_84561::test3
-Raw bytes (315): 0x[01, 01, 1b, 1d, 21, 25, 29, 21, 25, 2d, 31, 21, 17, 25, 2d, 41, 45, 49, 4d, 51, 55, 33, 51, 49, 4d, 33, 37, 49, 4d, 51, 59, 55, 59, 55, 59, 47, 5d, 55, 59, 61, 65, 71, 75, 69, 6d, 69, 6d, 69, 6d, 63, 79, 71, 75, 79, 7d, 7d, 81, 01, 33, 01, 08, 01, 03, 0f, 05, 04, 09, 01, 0f, 09, 02, 05, 04, 0f, 0d, 05, 05, 00, 0f, 11, 01, 05, 00, 0f, 15, 01, 09, 01, 0f, 19, 02, 05, 00, 0f, 1d, 01, 05, 00, 0f, 02, 00, 20, 00, 30, 21, 01, 05, 03, 0f, 25, 03, 20, 00, 30, 29, 00, 33, 00, 41, 06, 00, 4b, 00, 5a, 0a, 01, 05, 00, 0f, 2d, 05, 09, 03, 10, 31, 05, 0d, 00, 1b, 0e, 02, 0d, 00, 1c, 12, 04, 09, 02, 0f, 35, 06, 05, 00, 0f, 39, 04, 05, 00, 0f, 3d, 04, 09, 01, 0f, 41, 05, 08, 00, 0f, 45, 01, 09, 00, 13, 1a, 05, 09, 00, 13, 33, 05, 08, 00, 0f, 51, 01, 09, 00, 13, 22, 03, 0d, 00, 1d, 26, 03, 09, 00, 13, 2e, 03, 0d, 00, 1d, 47, 03, 05, 00, 0f, 47, 01, 0c, 00, 13, 5d, 01, 0d, 00, 13, 42, 02, 0d, 00, 13, 61, 04, 05, 02, 13, 65, 03, 0d, 00, 13, 4a, 02, 0d, 00, 13, 63, 03, 05, 00, 0f, 69, 01, 0c, 00, 13, 6d, 01, 0d, 00, 17, 71, 04, 0d, 00, 13, 5a, 02, 0d, 00, 17, 5a, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, 5a, 02, 15, 00, 1b, 75, 04, 0d, 00, 13, 5e, 03, 09, 00, 19, 79, 02, 05, 00, 0f, 66, 03, 09, 00, 22, 7d, 02, 05, 00, 0f, 6a, 03, 09, 00, 2c, 81, 01, 02, 01, 00, 02]
+Raw bytes (279): 0x[01, 01, 0a, 0d, 11, 0d, 15, 0d, 19, 1d, 21, 29, 2d, 25, 29, 25, 29, 25, 29, 27, 31, 29, 2d, 33, 01, 08, 01, 03, 0f, 05, 04, 09, 01, 0f, 09, 02, 05, 04, 0f, 09, 05, 05, 00, 0f, 09, 01, 05, 00, 0f, 09, 01, 09, 01, 0f, 0d, 02, 05, 00, 0f, 0d, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 0d, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 0d, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 0d, 04, 09, 02, 0f, 0d, 06, 05, 00, 0f, 0d, 04, 05, 00, 0f, 0d, 04, 09, 01, 0f, 0d, 05, 08, 00, 0f, 11, 01, 09, 00, 13, 02, 05, 09, 00, 13, 0d, 05, 08, 00, 0f, 15, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 06, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 0d, 03, 05, 00, 0f, 0d, 01, 0c, 00, 13, 19, 01, 0d, 00, 13, 0a, 02, 0d, 00, 13, 1d, 04, 05, 02, 13, 21, 03, 0d, 00, 13, 0e, 02, 0d, 00, 13, 27, 03, 05, 00, 0f, 25, 01, 0c, 00, 13, 29, 01, 0d, 00, 17, 29, 04, 0d, 00, 13, 1e, 02, 0d, 00, 17, 1e, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, 1e, 02, 15, 00, 1b, 2d, 04, 0d, 00, 13, 22, 03, 09, 00, 19, 31, 02, 05, 00, 0f, 31, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
-Number of expressions: 27
-- expression 0 operands: lhs = Counter(7), rhs = Counter(8)
-- expression 1 operands: lhs = Counter(9), rhs = Counter(10)
-- expression 2 operands: lhs = Counter(8), rhs = Counter(9)
-- expression 3 operands: lhs = Counter(11), rhs = Counter(12)
-- expression 4 operands: lhs = Counter(8), rhs = Expression(5, Add)
-- expression 5 operands: lhs = Counter(9), rhs = Counter(11)
-- expression 6 operands: lhs = Counter(16), rhs = Counter(17)
-- expression 7 operands: lhs = Counter(18), rhs = Counter(19)
-- expression 8 operands: lhs = Counter(20), rhs = Counter(21)
-- expression 9 operands: lhs = Expression(12, Add), rhs = Counter(20)
-- expression 10 operands: lhs = Counter(18), rhs = Counter(19)
-- expression 11 operands: lhs = Expression(12, Add), rhs = Expression(13, Add)
-- expression 12 operands: lhs = Counter(18), rhs = Counter(19)
-- expression 13 operands: lhs = Counter(20), rhs = Counter(22)
-- expression 14 operands: lhs = Counter(21), rhs = Counter(22)
-- expression 15 operands: lhs = Counter(21), rhs = Counter(22)
-- expression 16 operands: lhs = Expression(17, Add), rhs = Counter(23)
-- expression 17 operands: lhs = Counter(21), rhs = Counter(22)
-- expression 18 operands: lhs = Counter(24), rhs = Counter(25)
-- expression 19 operands: lhs = Counter(28), rhs = Counter(29)
-- expression 20 operands: lhs = Counter(26), rhs = Counter(27)
-- expression 21 operands: lhs = Counter(26), rhs = Counter(27)
-- expression 22 operands: lhs = Counter(26), rhs = Counter(27)
-- expression 23 operands: lhs = Expression(24, Add), rhs = Counter(30)
-- expression 24 operands: lhs = Counter(28), rhs = Counter(29)
-- expression 25 operands: lhs = Counter(30), rhs = Counter(31)
-- expression 26 operands: lhs = Counter(31), rhs = Counter(32)
+Number of expressions: 10
+- expression 0 operands: lhs = Counter(3), rhs = Counter(4)
+- expression 1 operands: lhs = Counter(3), rhs = Counter(5)
+- expression 2 operands: lhs = Counter(3), rhs = Counter(6)
+- expression 3 operands: lhs = Counter(7), rhs = Counter(8)
+- expression 4 operands: lhs = Counter(10), rhs = Counter(11)
+- expression 5 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 6 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 7 operands: lhs = Counter(9), rhs = Counter(10)
+- expression 8 operands: lhs = Expression(9, Add), rhs = Counter(12)
+- expression 9 operands: lhs = Counter(10), rhs = Counter(11)
 Number of file 0 mappings: 51
 - Code(Counter(0)) at (prev + 8, 1) to (start + 3, 15)
 - Code(Counter(1)) at (prev + 4, 9) to (start + 1, 15)
 - Code(Counter(2)) at (prev + 2, 5) to (start + 4, 15)
-- Code(Counter(3)) at (prev + 5, 5) to (start + 0, 15)
-- Code(Counter(4)) at (prev + 1, 5) to (start + 0, 15)
-- Code(Counter(5)) at (prev + 1, 9) to (start + 1, 15)
-- Code(Counter(6)) at (prev + 2, 5) to (start + 0, 15)
-- Code(Counter(7)) at (prev + 1, 5) to (start + 0, 15)
-- Code(Expression(0, Sub)) at (prev + 0, 32) to (start + 0, 48)
+- Code(Counter(2)) at (prev + 5, 5) to (start + 0, 15)
+- Code(Counter(2)) at (prev + 1, 5) to (start + 0, 15)
+- Code(Counter(2)) at (prev + 1, 9) to (start + 1, 15)
+- Code(Counter(3)) at (prev + 2, 5) to (start + 0, 15)
+- Code(Counter(3)) at (prev + 1, 5) to (start + 0, 15)
+- Code(Zero) at (prev + 0, 32) to (start + 0, 48)
+- Code(Counter(3)) at (prev + 1, 5) to (start + 3, 15)
+- Code(Zero) at (prev + 3, 32) to (start + 0, 48)
+- Code(Zero) at (prev + 0, 51) to (start + 0, 65)
+- Code(Zero) at (prev + 0, 75) to (start + 0, 90)
+- Code(Counter(3)) at (prev + 1, 5) to (start + 0, 15)
+- Code(Zero) at (prev + 5, 9) to (start + 3, 16)
+- Code(Zero) at (prev + 5, 13) to (start + 0, 27)
+- Code(Zero) at (prev + 2, 13) to (start + 0, 28)
+- Code(Counter(3)) at (prev + 4, 9) to (start + 2, 15)
+- Code(Counter(3)) at (prev + 6, 5) to (start + 0, 15)
+- Code(Counter(3)) at (prev + 4, 5) to (start + 0, 15)
+- Code(Counter(3)) at (prev + 4, 9) to (start + 1, 15)
+- Code(Counter(3)) at (prev + 5, 8) to (start + 0, 15)
+- Code(Counter(4)) at (prev + 1, 9) to (start + 0, 19)
+- Code(Expression(0, Sub)) at (prev + 5, 9) to (start + 0, 19)
+    = (c3 - c4)
+- Code(Counter(3)) at (prev + 5, 8) to (start + 0, 15)
+- Code(Counter(5)) at (prev + 1, 9) to (start + 0, 19)
+- Code(Zero) at (prev + 3, 13) to (start + 0, 29)
+- Code(Expression(1, Sub)) at (prev + 3, 9) to (start + 0, 19)
+    = (c3 - c5)
+- Code(Zero) at (prev + 3, 13) to (start + 0, 29)
+- Code(Counter(3)) at (prev + 3, 5) to (start + 0, 15)
+- Code(Counter(3)) at (prev + 1, 12) to (start + 0, 19)
+- Code(Counter(6)) at (prev + 1, 13) to (start + 0, 19)
+- Code(Expression(2, Sub)) at (prev + 2, 13) to (start + 0, 19)
+    = (c3 - c6)
+- Code(Counter(7)) at (prev + 4, 5) to (start + 2, 19)
+- Code(Counter(8)) at (prev + 3, 13) to (start + 0, 19)
+- Code(Expression(3, Sub)) at (prev + 2, 13) to (start + 0, 19)
     = (c7 - c8)
-- Code(Counter(8)) at (prev + 1, 5) to (start + 3, 15)
-- Code(Counter(9)) at (prev + 3, 32) to (start + 0, 48)
-- Code(Counter(10)) at (prev + 0, 51) to (start + 0, 65)
-- Code(Expression(1, Sub)) at (prev + 0, 75) to (start + 0, 90)
+- Code(Expression(9, Add)) at (prev + 3, 5) to (start + 0, 15)
+    = (c10 + c11)
+- Code(Counter(9)) at (prev + 1, 12) to (start + 0, 19)
+- Code(Counter(10)) at (prev + 1, 13) to (start + 0, 23)
+- Code(Counter(10)) at (prev + 4, 13) to (start + 0, 19)
+- Code(Expression(7, Sub)) at (prev + 2, 13) to (start + 0, 23)
+    = (c9 - c10)
+- Code(Expression(7, Sub)) at (prev + 1, 20) to (start + 0, 27)
     = (c9 - c10)
-- Code(Expression(2, Sub)) at (prev + 1, 5) to (start + 0, 15)
-    = (c8 - c9)
-- Code(Counter(11)) at (prev + 5, 9) to (start + 3, 16)
-- Code(Counter(12)) at (prev + 5, 13) to (start + 0, 27)
-- Code(Expression(3, Sub)) at (prev + 2, 13) to (start + 0, 28)
-    = (c11 - c12)
-- Code(Expression(4, Sub)) at (prev + 4, 9) to (start + 2, 15)
-    = (c8 - (c9 + c11))
-- Code(Counter(13)) at (prev + 6, 5) to (start + 0, 15)
-- Code(Counter(14)) at (prev + 4, 5) to (start + 0, 15)
-- Code(Counter(15)) at (prev + 4, 9) to (start + 1, 15)
-- Code(Counter(16)) at (prev + 5, 8) to (start + 0, 15)
-- Code(Counter(17)) at (prev + 1, 9) to (start + 0, 19)
-- Code(Expression(6, Sub)) at (prev + 5, 9) to (start + 0, 19)
-    = (c16 - c17)
-- Code(Expression(12, Add)) at (prev + 5, 8) to (start + 0, 15)
-    = (c18 + c19)
-- Code(Counter(20)) at (prev + 1, 9) to (start + 0, 19)
-- Code(Expression(8, Sub)) at (prev + 3, 13) to (start + 0, 29)
-    = (c20 - c21)
-- Code(Expression(9, Sub)) at (prev + 3, 9) to (start + 0, 19)
-    = ((c18 + c19) - c20)
-- Code(Expression(11, Sub)) at (prev + 3, 13) to (start + 0, 29)
-    = ((c18 + c19) - (c20 + c22))
-- Code(Expression(17, Add)) at (prev + 3, 5) to (start + 0, 15)
-    = (c21 + c22)
-- Code(Expression(17, Add)) at (prev + 1, 12) to (start + 0, 19)
-    = (c21 + c22)
-- Code(Counter(23)) at (prev + 1, 13) to (start + 0, 19)
-- Code(Expression(16, Sub)) at (prev + 2, 13) to (start + 0, 19)
-    = ((c21 + c22) - c23)
-- Code(Counter(24)) at (prev + 4, 5) to (start + 2, 19)
-- Code(Counter(25)) at (prev + 3, 13) to (start + 0, 19)
-- Code(Expression(18, Sub)) at (prev + 2, 13) to (start + 0, 19)
-    = (c24 - c25)
-- Code(Expression(24, Add)) at (prev + 3, 5) to (start + 0, 15)
-    = (c28 + c29)
-- Code(Counter(26)) at (prev + 1, 12) to (start + 0, 19)
-- Code(Counter(27)) at (prev + 1, 13) to (start + 0, 23)
-- Code(Counter(28)) at (prev + 4, 13) to (start + 0, 19)
-- Code(Expression(22, Sub)) at (prev + 2, 13) to (start + 0, 23)
-    = (c26 - c27)
-- Code(Expression(22, Sub)) at (prev + 1, 20) to (start + 0, 27)
-    = (c26 - c27)
 - Code(Zero) at (prev + 1, 21) to (start + 0, 27)
-- Code(Expression(22, Sub)) at (prev + 2, 21) to (start + 0, 27)
-    = (c26 - c27)
-- Code(Counter(29)) at (prev + 4, 13) to (start + 0, 19)
-- Code(Expression(23, Sub)) at (prev + 3, 9) to (start + 0, 25)
-    = ((c28 + c29) - c30)
-- Code(Counter(30)) at (prev + 2, 5) to (start + 0, 15)
-- Code(Expression(25, Sub)) at (prev + 3, 9) to (start + 0, 34)
-    = (c30 - c31)
-- Code(Counter(31)) at (prev + 2, 5) to (start + 0, 15)
-- Code(Expression(26, Sub)) at (prev + 3, 9) to (start + 0, 44)
-    = (c31 - c32)
-- Code(Counter(32)) at (prev + 2, 1) to (start + 0, 2)
-Highest counter ID seen: c32
+- Code(Expression(7, Sub)) at (prev + 2, 21) to (start + 0, 27)
+    = (c9 - c10)
+- Code(Counter(11)) at (prev + 4, 13) to (start + 0, 19)
+- Code(Expression(8, Sub)) at (prev + 3, 9) to (start + 0, 25)
+    = ((c10 + c11) - c12)
+- Code(Counter(12)) at (prev + 2, 5) to (start + 0, 15)
+- Code(Counter(12)) at (prev + 3, 9) to (start + 0, 34)
+- Code(Zero) at (prev + 2, 5) to (start + 0, 15)
+- Code(Zero) at (prev + 3, 9) to (start + 0, 44)
+- Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c12
 

tests/coverage/issue-84561.cov-map

@@ -8,8 +8,9 @@
 
       bb0: {
           StorageLive(_1);
-          _1 = const <bool as NeedsDrop>::NEEDS;
+-         _1 = const <bool as NeedsDrop>::NEEDS;
 -         switchInt(move _1) -> [0: bb2, otherwise: bb1];
++         _1 = const false;
 +         switchInt(const false) -> [0: bb2, otherwise: bb1];
       }
 

tests/mir-opt/const_prop/control_flow_simplification.hello.GVN.panic-abort.diff

@@ -8,8 +8,9 @@
 
       bb0: {
           StorageLive(_1);
-          _1 = const <bool as NeedsDrop>::NEEDS;
+-         _1 = const <bool as NeedsDrop>::NEEDS;
 -         switchInt(move _1) -> [0: bb2, otherwise: bb1];
++         _1 = const false;
 +         switchInt(const false) -> [0: bb2, otherwise: bb1];
       }
 

tests/mir-opt/const_prop/control_flow_simplification.hello.GVN.panic-unwind.diff

@@ -14,19 +14,23 @@
 
       bb0: {
           StorageLive(_1);
-          StorageLive(_2);
+-         StorageLive(_2);
 -         StorageLive(_3);
++         nop;
 +         nop;
           _3 = const {ALLOC0: &u8};
-          _2 = copy (*_3);
+-         _2 = copy (*_3);
++         _2 = const 2_u8;
           StorageLive(_4);
           StorageLive(_5);
           _5 = const {ALLOC0: &u8};
 -         _4 = copy (*_5);
-+         _4 = copy (*_3);
-          _1 = Add(move _2, move _4);
+-         _1 = Add(move _2, move _4);
++         _4 = const 2_u8;
++         _1 = const 4_u8;
           StorageDead(_4);
-          StorageDead(_2);
+-         StorageDead(_2);
++         nop;
           StorageDead(_5);
 -         StorageDead(_3);
 +         nop;

tests/mir-opt/const_prop/read_immutable_static.main.GVN.diff

@@ -6,7 +6,6 @@ static FOO: u8 = 2;
 fn main() {
     // CHECK-LABEL: fn main(
     // CHECK: debug x => [[x:_.*]];
-    // Disabled due to <https://github.com/rust-lang/rust/issues/130853>
-    // COM: CHECK: [[x]] = const 4_u8;
+    // CHECK: [[x]] = const 4_u8;
     let x = FOO + FOO;
 }