Update compiler/rustc_middle/src/query/mod.rs

nikomatsakis · LeSeulArtichaut · web-flow · commit 9385be7a0cc9 · 2021-05-27T10:31:47.000-04:00
Co-authored-by: Léo Lanteri Thauvin &lt;leseulartichaut@gmail.com&gt;
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
@@ -222,6 +222,7 @@ rustc_queries! {
 
     /// Fetch the THIR for a given body. If typeck for that body failed, returns an empty `Thir`.
     query thir_body(key: ty::WithOptConstParam<LocalDefId>) -> (&'tcx Steal<thir::Thir<'tcx>>, thir::ExprId) {
+        // Perf tests revealed that hashing THIR is inefficient (see #85729).
         no_hash
         desc { |tcx| "building THIR for `{}`", tcx.def_path_str(key.did.to_def_id()) }
     }

Original file line number	Diff line number	Diff line change
`@@ -222,6 +222,7 @@ rustc_queries! {`
`222`	`222`
`223`	`223`	/// Fetch the THIR for a given body. If typeck for that body failed, returns an empty `Thir`.
`224`	`224`	`query thir_body(key: ty::WithOptConstParam<LocalDefId>) -> (&'tcx Steal<thir::Thir<'tcx>>, thir::ExprId) {`
	`225`	`+ // Perf tests revealed that hashing THIR is inefficient (see #85729).`
`225`	`226`	`no_hash`
`226`	`227`	desc { \|tcx\| "building THIR for `{}`", tcx.def_path_str(key.did.to_def_id()) }
`227`	`228`	`}`