From ef731b31dbd5f1dccf4a863290c8286b9601e323 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= Date: Wed, 24 Feb 2021 00:00:00 +0000 Subject: [PATCH] Use small hash set in `mir_inliner_callees` Use small hash set in `mir_inliner_callees` to avoid temporary allocation when possible and quadratic behaviour for large number of callees. --- compiler/rustc_mir/src/transform/inline/cycle.rs | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/compiler/rustc_mir/src/transform/inline/cycle.rs b/compiler/rustc_mir/src/transform/inline/cycle.rs index 4c24bec0ce3ad..295f3ec70dc78 100644 --- a/compiler/rustc_mir/src/transform/inline/cycle.rs +++ b/compiler/rustc_mir/src/transform/inline/cycle.rs @@ -1,4 +1,5 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_data_structures::sso::SsoHashSet; use rustc_data_structures::stack::ensure_sufficient_stack; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_middle::mir::TerminatorKind; @@ -140,7 +141,7 @@ crate fn mir_inliner_callees<'tcx>( // Functions from other crates and MIR shims _ => tcx.instance_mir(instance), }; - let mut calls = Vec::new(); + let mut calls = SsoHashSet::new(); for bb_data in body.basic_blocks() { let terminator = bb_data.terminator(); if let TerminatorKind::Call { func, .. } = &terminator.kind { @@ -149,12 +150,8 @@ crate fn mir_inliner_callees<'tcx>( ty::FnDef(def_id, substs) => (*def_id, *substs), _ => continue, }; - // We've seen this before - if calls.contains(&call) { - continue; - } - calls.push(call); + calls.insert(call); } } - tcx.arena.alloc_slice(&calls) + tcx.arena.alloc_from_iter(calls.iter().copied()) }