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| author | Ralf Jung <post@ralfj.de> | 2023-10-10 11:17:27 +0200 |
|---|---|---|
| committer | Ralf Jung <post@ralfj.de> | 2023-10-10 11:17:27 +0200 |
| commit | d805b265dbc254cb9b8cee8c9a1eff9cd161a87a (patch) | |
| tree | a86fcd56ce9832e8f2ee5415ce682c901f84a756 | |
| parent | 2de454637f56c678e33f4de83d50a5b27b46e56a (diff) | |
| download | rust-d805b265dbc254cb9b8cee8c9a1eff9cd161a87a.tar.gz rust-d805b265dbc254cb9b8cee8c9a1eff9cd161a87a.zip | |
add some comments explaining why MIR opts are marked as unsound
| -rw-r--r-- | compiler/rustc_mir_transform/src/early_otherwise_branch.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/large_enums.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_mir_transform/src/nrvo.rs | 2 |
3 files changed, 5 insertions, 1 deletions
diff --git a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs index 319fb4eaf3e..6eb6cb069fe 100644 --- a/compiler/rustc_mir_transform/src/early_otherwise_branch.rs +++ b/compiler/rustc_mir_transform/src/early_otherwise_branch.rs @@ -95,6 +95,7 @@ pub struct EarlyOtherwiseBranch; impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch { fn is_enabled(&self, sess: &rustc_session::Session) -> bool { + // unsound: https://github.com/rust-lang/rust/issues/95162 sess.mir_opt_level() >= 3 && sess.opts.unstable_opts.unsound_mir_opts } diff --git a/compiler/rustc_mir_transform/src/large_enums.rs b/compiler/rustc_mir_transform/src/large_enums.rs index 886ff760481..0a8b13d6677 100644 --- a/compiler/rustc_mir_transform/src/large_enums.rs +++ b/compiler/rustc_mir_transform/src/large_enums.rs @@ -30,6 +30,9 @@ pub struct EnumSizeOpt { impl<'tcx> MirPass<'tcx> for EnumSizeOpt { fn is_enabled(&self, sess: &Session) -> bool { + // There are some differences in behavior on wasm and ARM that are not properly + // understood, so we conservatively treat this optimization as unsound: + // https://github.com/rust-lang/rust/pull/85158#issuecomment-1101836457 sess.opts.unstable_opts.unsound_mir_opts || sess.mir_opt_level() >= 3 } fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { diff --git a/compiler/rustc_mir_transform/src/nrvo.rs b/compiler/rustc_mir_transform/src/nrvo.rs index e1298b0654f..ff309bd10ec 100644 --- a/compiler/rustc_mir_transform/src/nrvo.rs +++ b/compiler/rustc_mir_transform/src/nrvo.rs @@ -34,7 +34,7 @@ pub struct RenameReturnPlace; impl<'tcx> MirPass<'tcx> for RenameReturnPlace { fn is_enabled(&self, sess: &rustc_session::Session) -> bool { - // #111005 + // unsound: #111005 sess.mir_opt_level() > 0 && sess.opts.unstable_opts.unsound_mir_opts } |