Mark early otherwise optimization unsound

rust-lang · Mar 18, 2021 · 778e197 · 778e197
1 parent 1705a7d
commit 778e197
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Showing 3 changed files with 7 additions and 2 deletions.
diff --git a/compiler/rustc_mir/src/transform/early_otherwise_branch.rs b/compiler/rustc_mir/src/transform/early_otherwise_branch.rs
@@ -26,6 +26,11 @@ pub struct EarlyOtherwiseBranch;
 
 impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+        //  FIXME(#78496)
+        if !tcx.sess.opts.debugging_opts.unsound_mir_opts {
+            return;
+        }
+
         if tcx.sess.mir_opt_level() < 3 {
             return;
         }

diff --git a/src/test/mir-opt/early_otherwise_branch.rs b/src/test/mir-opt/early_otherwise_branch.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z mir-opt-level=4
+// compile-flags: -Z mir-opt-level=4 -Z unsound-mir-opts
 // EMIT_MIR early_otherwise_branch.opt1.EarlyOtherwiseBranch.diff
 fn opt1(x: Option<u32>, y: Option<u32>) -> u32 {
     match (x, y) {

diff --git a/src/test/mir-opt/early_otherwise_branch_3_element_tuple.rs b/src/test/mir-opt/early_otherwise_branch_3_element_tuple.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Z mir-opt-level=4
+// compile-flags: -Z mir-opt-level=4 -Z unsound-mir-opts
 
 // EMIT_MIR early_otherwise_branch_3_element_tuple.opt1.EarlyOtherwiseBranch.diff
 fn opt1(x: Option<u32>, y: Option<u32>, z: Option<u32>) -> u32 {