rustc_mir_transform/
remove_place_mention.rs

1//! This pass removes `PlaceMention` statement, which has no effect at codegen.
2
3use rustc_middle::mir::*;
4use rustc_middle::ty::TyCtxt;
5use tracing::trace;
6
7pub(super) struct RemovePlaceMention;
8
9impl<'tcx> crate::MirPass<'tcx> for RemovePlaceMention {
10    fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
11        !sess.opts.unstable_opts.mir_keep_place_mention
12    }
13
14    fn run_pass(&self, _: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
15        trace!("Running RemovePlaceMention on {:?}", body.source);
16        for data in body.basic_blocks.as_mut_preserves_cfg() {
17            data.statements.retain(|statement| match statement.kind {
18                StatementKind::PlaceMention(..) | StatementKind::Nop => false,
19                _ => true,
20            })
21        }
22    }
23
24    fn is_required(&self) -> bool {
25        true
26    }
27}