Lower the assume intrinsic to a MIR statement

compiler/rustc_mir_transform/src/check_unsafety.rs

@@ -105,6 +105,9 @@ impl<'tcx> Visitor<'tcx> for UnsafetyChecker<'_, 'tcx> {
                 // safe (at least as emitted during MIR construction)
             }
 
+            // Move to above list once mir construction uses it.
+            StatementKind::Assume(..) => unreachable!(),
+
             StatementKind::CopyNonOverlapping(..) => unreachable!(),
         }
         self.super_statement(statement, location);

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -826,6 +826,7 @@ pub(super) fn filtered_statement_span(statement: &Statement<'_>) -> Option<Span>
         // Retain spans from all other statements
         StatementKind::FakeRead(box (_, _)) // Not including `ForGuardBinding`
         | StatementKind::CopyNonOverlapping(..)
+        | StatementKind::Assume(..)
         | StatementKind::Assign(_)
         | StatementKind::SetDiscriminant { .. }
         | StatementKind::Deinit(..)

compiler/rustc_mir_transform/src/dead_store_elimination.rs

@@ -53,6 +53,7 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS
                 | StatementKind::StorageDead(_)
                 | StatementKind::Coverage(_)
                 | StatementKind::CopyNonOverlapping(_)
+                | StatementKind::Assume(_)
                 | StatementKind::Nop => (),
 
                 StatementKind::FakeRead(_) | StatementKind::AscribeUserType(_, _) => {

compiler/rustc_mir_transform/src/dest_prop.rs

@@ -538,6 +538,7 @@ impl<'a> Conflicts<'a> {
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
             | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Assume(..)
             | StatementKind::Nop => {}
         }
     }

compiler/rustc_mir_transform/src/generator.rs

@@ -1453,6 +1453,7 @@ impl<'tcx> Visitor<'tcx> for EnsureGeneratorFieldAssignmentsNeverAlias<'_> {
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
             | StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Assume(..)
             | StatementKind::Nop => {}
         }
     }

compiler/rustc_mir_transform/src/lower_intrinsics.rs

@@ -62,6 +62,17 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
                         drop(args);
                         terminator.kind = TerminatorKind::Goto { target };
                     }
+                    sym::assume => {
+                        let target = target.unwrap();
+                        let mut args = args.drain(..);
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::Assume(Box::new(args.next().unwrap())),
+                        });
+                        assert_eq!(args.next(), None, "Extra argument for assume intrinsic");
+                        drop(args);
+                        terminator.kind = TerminatorKind::Goto { target };
+                    }
                     sym::wrapping_add | sym::wrapping_sub | sym::wrapping_mul => {
                         if let Some(target) = *target {
                             let lhs;

compiler/rustc_mir_transform/src/remove_noop_landing_pads.rs

@@ -52,6 +52,7 @@ impl RemoveNoopLandingPads {
                 | StatementKind::SetDiscriminant { .. }
                 | StatementKind::Deinit(..)
                 | StatementKind::CopyNonOverlapping(..)
+                | StatementKind::Assume(..)
                 | StatementKind::Retag { .. } => {
                     return false;
                 }

compiler/rustc_mir_transform/src/separate_const_switch.rs

@@ -250,6 +250,7 @@ fn is_likely_const<'tcx>(mut tracked_place: Place<'tcx>, block: &BasicBlockData<
             | StatementKind::Coverage(_)
             | StatementKind::StorageDead(_)
             | StatementKind::CopyNonOverlapping(_)
+            | StatementKind::Assume(_)
             | StatementKind::Nop => {}
         }
     }
@@ -318,6 +319,7 @@ fn find_determining_place<'tcx>(
             | StatementKind::AscribeUserType(_, _)
             | StatementKind::Coverage(_)
             | StatementKind::CopyNonOverlapping(_)
+            | StatementKind::Assume(_)
             | StatementKind::Nop => {}
 
             // If the discriminant is set, it is always set

compiler/rustc_mir_transform/src/simplify.rs

@@ -500,6 +500,7 @@ impl<'tcx> Visitor<'tcx> for UsedLocals {
     fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         match statement.kind {
             StatementKind::CopyNonOverlapping(..)
+            | StatementKind::Assume(..)
             | StatementKind::Retag(..)
             | StatementKind::Coverage(..)
             | StatementKind::FakeRead(..)