From e5d50e3e88f88e8a8b20e90bb0d561e1ed71fe5f Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Thu, 5 Dec 2019 14:38:24 +0100
Subject: [PATCH] comments

---
 src/librustc_codegen_ssa/mir/operand.rs | 5 +++--
 src/librustc_codegen_ssa/mir/place.rs   | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs
index 310b8aeb4db09..a6dec81274915 100644
--- a/src/librustc_codegen_ssa/mir/operand.rs
+++ b/src/librustc_codegen_ssa/mir/operand.rs
@@ -475,9 +475,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             },
                         }
                         // Allow RalfJ to sleep soundly knowing that even refactorings that remove
-                        // the above error (or silence it under some conditions) will not cause UB
+                        // the above error (or silence it under some conditions) will not cause UB.
                         bx.abort();
-                        // We've errored, so we don't have to produce working code.
+                        // We still have to return an operand but it doesn't matter,
+                        // this code is unreachable.
                         let ty = self.monomorphize(&constant.literal.ty);
                         let layout = bx.cx().layout_of(ty);
                         bx.load_operand(PlaceRef::new_sized(
diff --git a/src/librustc_codegen_ssa/mir/place.rs b/src/librustc_codegen_ssa/mir/place.rs
index 4b8819d11f4f8..b8ff2249dcb04 100644
--- a/src/librustc_codegen_ssa/mir/place.rs
+++ b/src/librustc_codegen_ssa/mir/place.rs
@@ -493,6 +493,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                         // With floats that won't always be true,
                         // so we generate a (safe) abort.
                         bx.abort();
+                        // We still have to return a place but it doesn't matter,
+                        // this code is unreachable.
                         let llval = bx.cx().const_undef(
                             bx.cx().type_ptr_to(bx.cx().backend_type(layout))
                         );