Auto merge of #71106 - jonas-schievink:remove-call-guard-pass, r=ecst…

…atic-morse,RalfJung

Don't always run `add_call_guards` pass

It is only needed when `add_retag` runs.

(the pass is run again to split critical edges before codegen, that one is required)

src/librustc_mir/transform/add_retag.rs

@@ -58,10 +58,14 @@ fn may_be_reference(ty: Ty<'tcx>) -> bool {
 }
 
 impl<'tcx> MirPass<'tcx> for AddRetag {
-    fn run_pass(&self, tcx: TyCtxt<'tcx>, _src: MirSource<'tcx>, body: &mut BodyAndCache<'tcx>) {
+    fn run_pass(&self, tcx: TyCtxt<'tcx>, src: MirSource<'tcx>, body: &mut BodyAndCache<'tcx>) {
         if !tcx.sess.opts.debugging_opts.mir_emit_retag {
             return;
         }
+
+        // We need an `AllCallEdges` pass before we can do any work.
+        super::add_call_guards::AllCallEdges.run_pass(tcx, src, body);
+
         let (span, arg_count) = (body.span, body.arg_count);
         let (basic_blocks, local_decls) = body.basic_blocks_and_local_decls_mut();
         let needs_retag = |place: &Place<'tcx>| {

src/librustc_mir/transform/mod.rs

@@ -287,10 +287,8 @@ fn run_optimization_passes<'tcx>(
             // AddMovesForPackedDrops needs to run after drop
             // elaboration.
             &add_moves_for_packed_drops::AddMovesForPackedDrops,
-            // AddRetag needs to run after ElaborateDrops, and it needs
-            // an AllCallEdges pass right before it.  Otherwise it should
-            // run fairly late, but before optimizations begin.
-            &add_call_guards::AllCallEdges,
+            // `AddRetag` needs to run after `ElaborateDrops`. Otherwise it should run fairly late,
+            // but before optimizations begin.
             &add_retag::AddRetag,
             &simplify::SimplifyCfg::new("elaborate-drops"),
             // No lifetime analysis based on borrowing can be done from here on out.