bjoernager/rust
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Optimize relate_substs by extracting match

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There was no need to keep doing the match inside the iterator.
This commit is contained in:
Martin Gammelsæter 2022-04-13 17:46:29 +02:00
parent 4e1927db3c
commit 041121a184
1 changed files with 12 additions and 12 deletions
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20
compiler/rustc_middle/src/ty/relate.rs
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@ -142,11 +142,12 @@ pub fn relate_substs<'tcx, R: TypeRelation<'tcx>>(
b_subst: SubstsRef<'tcx>, b_subst: SubstsRef<'tcx>,
) -> RelateResult<'tcx, SubstsRef<'tcx>> { ) -> RelateResult<'tcx, SubstsRef<'tcx>> {
let tcx = relation.tcx(); let tcx = relation.tcx();
let mut cached_ty = None;
let params = iter::zip(a_subst, b_subst).enumerate().map(|(i, (a, b))| { let zipped = iter::zip(a_subst, b_subst);
let (variance, variance_info) = match variances { match variances {
Some((ty_def_id, variances)) => { Some((ty_def_id, variances)) => {
let mut cached_ty = None;
tcx.mk_substs(zipped.enumerate().map(|(i, (a, b))| {
let variance = variances[i]; let variance = variances[i];
let variance_info = if variance == ty::Invariant { let variance_info = if variance == ty::Invariant {
let ty = *cached_ty let ty = *cached_ty
@ -155,14 +156,13 @@ pub fn relate_substs<'tcx, R: TypeRelation<'tcx>>(
} else { } else {
ty::VarianceDiagInfo::default() ty::VarianceDiagInfo::default()
}; };
(variance, variance_info)
}
None => (ty::Invariant, ty::VarianceDiagInfo::default()),
};
relation.relate_with_variance(variance, variance_info, a, b) relation.relate_with_variance(variance, variance_info, a, b)
}); }))
}
tcx.mk_substs(params) None => tcx.mk_substs(zipped.map(|(a, b)| {
relation.relate_with_variance(ty::Invariant, ty::VarianceDiagInfo::default(), a, b)
})),
}
} }
impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> { impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {