bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Auto merge of #139292 - compiler-errors:folder-experiment-7, r=lqd

Browse source 
Folder experiment: Micro-optimize RegionEraserVisitor

**NOTE:** This is one of a series of perf experiments that I've come up with while sick in bed. I'm assigning them to lqd b/c you're a good reviewer and you'll hopefully be awake when these experiments finish, lol.

r? lqd

The region eraser is very hot, so let's see if we can avoid erasing types (and visiting consts and preds that don't have region-ful types) unnecessarily.
This commit is contained in:
bors 2025-04-05 12:33:47 +00:00
commit 0c478fdfe1
1 changed files with 23 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

24
compiler/rustc_middle/src/ty/erase_regions.rs
View file

@ -44,7 +44,13 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RegionEraserVisitor<'tcx> {
}
fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
if ty.has_infer() { ty.super_fold_with(self) } else { self.tcx.erase_regions_ty(ty) }
if !ty.has_type_flags(TypeFlags::HAS_BINDER_VARS | TypeFlags::HAS_FREE_REGIONS) {
ty
} else if ty.has_infer() {
ty.super_fold_with(self)
} else {
self.tcx.erase_regions_ty(ty)
}
}
fn fold_binder<T>(&mut self, t: ty::Binder<'tcx, T>) -> ty::Binder<'tcx, T>
@ -64,4 +70,20 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for RegionEraserVisitor<'tcx> {
_ => self.tcx.lifetimes.re_erased,
}
}
fn fold_const(&mut self, ct: ty::Const<'tcx>) -> ty::Const<'tcx> {
if ct.has_type_flags(TypeFlags::HAS_BINDER_VARS | TypeFlags::HAS_FREE_REGIONS) {
ct.super_fold_with(self)
} else {
ct
}
}
fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> {
if p.has_type_flags(TypeFlags::HAS_BINDER_VARS | TypeFlags::HAS_FREE_REGIONS) {
p.super_fold_with(self)
} else {
p
}
}
}