diff options
| author | Nilstrieb <48135649+Nilstrieb@users.noreply.github.com> | 2022-07-26 15:15:07 +0200 |
|---|---|---|
| committer | Nilstrieb <48135649+Nilstrieb@users.noreply.github.com> | 2022-08-21 21:15:28 +0200 |
| commit | bc79557311f068cbd97e77507797d912dc637180 (patch) | |
| tree | d9f30f31ba95fbcbbc0a8d00de0eb1d89b383aeb | |
| parent | eafab660964bcd1e2c8b19cc2021cc5c7fee6c38 (diff) | |
Enable UnreachablePropagation under mir-opt-level >= 2
It was disabled because of pathological behaviour of LLVM in some benchmarks. As of #77680, this has been fixed. The problem there was that it caused pessimizations in some cases. These have now been fixed as well.
| -rw-r--r-- | compiler/rustc_mir_transform/src/unreachable_prop.rs | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/compiler/rustc_mir_transform/src/unreachable_prop.rs b/compiler/rustc_mir_transform/src/unreachable_prop.rs index a7e522beeab..56d7799a125 100644 --- a/compiler/rustc_mir_transform/src/unreachable_prop.rs +++ b/compiler/rustc_mir_transform/src/unreachable_prop.rs @@ -12,9 +12,8 @@ pub struct UnreachablePropagation; impl MirPass<'_> for UnreachablePropagation { fn is_enabled(&self, sess: &rustc_session::Session) -> bool { - // Enable only under -Zmir-opt-level=4 as in some cases (check the deeply-nested-opt - // perf benchmark) LLVM may spend quite a lot of time optimizing the generated code. - sess.mir_opt_level() >= 4 + // Enable only under -Zmir-opt-level=2 as this can make programs less debuggable. + sess.mir_opt_level() >= 2 } fn run_pass<'tcx>(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { |