From edd08e020cb1269a0f171e0502d8bc166c78e58b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Fri, 7 Dec 2018 00:56:19 +0100
Subject: [PATCH] Optimize away a move
---
src/librustc/ty/query/plumbing.rs | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index a73b92ed713ec..3f90f072ddbdf 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -136,11 +136,14 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
Entry::Vacant(entry) => {
// No job entry for this query. Return a new one to be started later
return tls::with_related_context(tcx, |icx| {
+ // Create the `parent` variable before `info`. This allows LLVM
+ // to elide the move of `info`
+ let parent = icx.query.clone();
let info = QueryInfo {
span,
query: Q::query(key.clone()),
};
- let job = Lrc::new(QueryJob::new(info, icx.query.clone()));
+ let job = Lrc::new(QueryJob::new(info, parent));
let owner = JobOwner {
cache,
job: job.clone(),