Auto merge of #136593 - lukas-code:ty-value-perf, r=<try>

[perf] try to mitigate regression in fast reject for `ty::Value`

#136318 (comment)

r? ghost

Author: bors

compiler/rustc_middle/src/ty/consts.rs

@@ -34,6 +34,12 @@ impl<'tcx> rustc_type_ir::inherent::IntoKind for Const<'tcx> {
     }
 }
 
+impl<'tcx> rustc_type_ir::inherent::IntoKindRef for Const<'tcx> {
+    fn kind_ref(&self) -> &ConstKind<'tcx> {
+        (*self).kind_ref()
+    }
+}
+
 impl<'tcx> rustc_type_ir::visit::Flags for Const<'tcx> {
     fn flags(&self) -> TypeFlags {
         self.0.flags
@@ -47,8 +53,12 @@ impl<'tcx> rustc_type_ir::visit::Flags for Const<'tcx> {
 impl<'tcx> Const<'tcx> {
     #[inline]
     pub fn kind(self) -> ConstKind<'tcx> {
-        let a: &ConstKind<'tcx> = self.0.0;
-        *a
+        *self.kind_ref()
+    }
+
+    #[inline]
+    pub fn kind_ref(self) -> &'tcx ConstKind<'tcx> {
+        self.0.0
     }
 
     // FIXME(compiler-errors): Think about removing this.

compiler/rustc_middle/src/ty/consts/valtree.rs

@@ -145,11 +145,11 @@ impl<'tcx> Value<'tcx> {
 }
 
 impl<'tcx> rustc_type_ir::inherent::ValueConst<TyCtxt<'tcx>> for Value<'tcx> {
-    fn ty(self) -> Ty<'tcx> {
+    fn ty(&self) -> Ty<'tcx> {
         self.ty
     }
 
-    fn valtree(self) -> ValTree<'tcx> {
-        self.valtree
+    fn valtree(&self) -> &ValTree<'tcx> {
+        &self.valtree
     }
 }

compiler/rustc_type_ir/src/fast_reject.rs

@@ -464,7 +464,8 @@ impl<I: Interner, const INSTANTIATE_LHS_WITH_INFER: bool, const INSTANTIATE_RHS_
     // Unlike `types_may_unify_inner`, this does not take a depth as
     // we never recurse from this function.
     fn consts_may_unify_inner(self, lhs: I::Const, rhs: I::Const) -> bool {
-        match rhs.kind() {
+        let rhs_kind = rhs.kind_ref();
+        match *rhs_kind {
             ty::ConstKind::Param(_) => {
                 if INSTANTIATE_RHS_WITH_INFER {
                     return true;
@@ -482,23 +483,24 @@ impl<I: Interner, const INSTANTIATE_LHS_WITH_INFER: bool, const INSTANTIATE_RHS_
             ty::ConstKind::Value(..) | ty::ConstKind::Placeholder(_) => {}
         };
 
-        match lhs.kind() {
-            ty::ConstKind::Value(lhs_val) => match rhs.kind() {
-                ty::ConstKind::Value(rhs_val) => lhs_val.valtree() == rhs_val.valtree(),
+        let lhs_kind = lhs.kind_ref();
+        match *lhs_kind {
+            ty::ConstKind::Value(ref lhs_val) => match *rhs_kind {
+                ty::ConstKind::Value(ref rhs_val) => lhs_val.valtree() == rhs_val.valtree(),
                 _ => false,
             },
 
             ty::ConstKind::Param(lhs) => {
                 INSTANTIATE_LHS_WITH_INFER
-                    || match rhs.kind() {
+                    || match *rhs_kind {
                         ty::ConstKind::Param(rhs) => lhs == rhs,
                         _ => false,
                     }
             }
 
             // Placeholder consts don't unify with anything on their own
             ty::ConstKind::Placeholder(lhs) => {
-                matches!(rhs.kind(), ty::ConstKind::Placeholder(rhs) if lhs == rhs)
+                matches!(*rhs_kind, ty::ConstKind::Placeholder(rhs) if lhs == rhs)
             }
 
             // As we don't necessarily eagerly evaluate constants,

compiler/rustc_type_ir/src/inherent.rs

@@ -257,7 +257,7 @@ pub trait Const<I: Interner<Const = Self>>:
     + Eq
     + Into<I::GenericArg>
     + Into<I::Term>
-    + IntoKind<Kind = ty::ConstKind<I>>
+    + IntoKindRef<Kind = ty::ConstKind<I>>
     + TypeSuperVisitable<I>
     + TypeSuperFoldable<I>
     + Relate<I>
@@ -287,8 +287,8 @@ pub trait Const<I: Interner<Const = Self>>:
 }
 
 pub trait ValueConst<I: Interner<ValueConst = Self>>: Copy + Debug + Hash + Eq {
-    fn ty(self) -> I::Ty;
-    fn valtree(self) -> I::ValTree;
+    fn ty(&self) -> I::Ty;
+    fn valtree(&self) -> &I::ValTree;
 }
 
 pub trait ExprConst<I: Interner<ExprConst = Self>>: Copy + Debug + Hash + Eq + Relate<I> {
@@ -518,6 +518,10 @@ pub trait IntoKind {
     fn kind(self) -> Self::Kind;
 }
 
+pub trait IntoKindRef: IntoKind {
+    fn kind_ref(&self) -> &Self::Kind;
+}
+
 pub trait BoundVarLike<I: Interner> {
     fn var(self) -> ty::BoundVar;