diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/util/alignment.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_const_eval/src/util/mod.rs | 2 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/dead_store_elimination.rs | 10 |
3 files changed, 8 insertions, 6 deletions
diff --git a/compiler/rustc_const_eval/src/util/alignment.rs b/compiler/rustc_const_eval/src/util/alignment.rs index 4f39dad205a..c1f0ff260d2 100644 --- a/compiler/rustc_const_eval/src/util/alignment.rs +++ b/compiler/rustc_const_eval/src/util/alignment.rs @@ -40,7 +40,7 @@ where } } -fn is_within_packed<'tcx, L>( +pub fn is_within_packed<'tcx, L>( tcx: TyCtxt<'tcx>, local_decls: &L, place: Place<'tcx>, diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs index 289e3422595..0aef7fa469e 100644 --- a/compiler/rustc_const_eval/src/util/mod.rs +++ b/compiler/rustc_const_eval/src/util/mod.rs @@ -5,7 +5,7 @@ mod check_validity_requirement; mod compare_types; mod type_name; -pub use self::alignment::is_disaligned; +pub use self::alignment::{is_disaligned, is_within_packed}; pub use self::check_validity_requirement::check_validity_requirement; pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype}; pub use self::type_name::type_name; diff --git a/compiler/rustc_mir_transform/src/dead_store_elimination.rs b/compiler/rustc_mir_transform/src/dead_store_elimination.rs index 47c1c465e56..ef14105041b 100644 --- a/compiler/rustc_mir_transform/src/dead_store_elimination.rs +++ b/compiler/rustc_mir_transform/src/dead_store_elimination.rs @@ -12,7 +12,7 @@ //! will still not cause any further changes. //! -use crate::util::is_disaligned; +use crate::util::is_within_packed; use rustc_index::bit_set::BitSet; use rustc_middle::mir::visit::Visitor; use rustc_middle::mir::*; @@ -32,8 +32,6 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS .iterate_to_fixpoint() .into_results_cursor(body); - let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id()); - // For blocks with a call terminator, if an argument copy can be turned into a move, // record it as (block, argument index). let mut call_operands_to_move = Vec::new(); @@ -52,7 +50,11 @@ pub fn eliminate<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>, borrowed: &BitS && !place.is_indirect() && !borrowed.contains(place.local) && !state.contains(place.local) - && !is_disaligned(tcx, body, param_env, place) + // If `place` is a projection of a disaligned field in a packed ADT, + // the move may be codegened as a pointer to that field. + // Using that disaligned pointer may trigger UB in the callee, + // so do nothing. + && is_within_packed(tcx, body, place).is_none() { call_operands_to_move.push((bb, index)); } |