From 981e11e8ce17834713d354cc95755ea8a7905c6a Mon Sep 17 00:00:00 2001
From: Dylan MacKenzie <ecstaticmorse@gmail.com>
Date: Sat, 2 Nov 2019 11:23:16 -0700
Subject: [PATCH] Don't double-count `simd_shuffle` promotion candidates

The proper attribute was added to `simd_shuffle*` in
rust-lang/stdarch#825. This caused `promote_consts` to double-count its
second argument when recording promotion candidates, which caused
the promotion candidate compatibility check to fail.
---
 src/librustc_mir/transform/promote_consts.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index 83f3aafc55cb1..f5e49e3283406 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -199,6 +199,8 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
                             bb: location.block,
                             index: 2,
                         });
+
+                        return; // Don't double count `simd_shuffle` candidates
                     }
                 }