From 5eae9452b6762a1347a3dec4f40c8ddc7789a868 Mon Sep 17 00:00:00 2001 From: Zalathar Date: Mon, 1 Jan 2024 22:59:47 +1100 Subject: [PATCH] coverage: Simplify computing successors in the BCB graph --- .../rustc_mir_transform/src/coverage/graph.rs | 21 +++++++------------ 1 file changed, 7 insertions(+), 14 deletions(-) diff --git a/compiler/rustc_mir_transform/src/coverage/graph.rs b/compiler/rustc_mir_transform/src/coverage/graph.rs index 9a3605b7a6a..c6badbe78a4 100644 --- a/compiler/rustc_mir_transform/src/coverage/graph.rs +++ b/compiler/rustc_mir_transform/src/coverage/graph.rs @@ -1,4 +1,5 @@ use rustc_data_structures::captures::Captures; +use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::graph::dominators::{self, Dominators}; use rustc_data_structures::graph::{self, GraphSuccessors, WithNumNodes, WithStartNode}; use rustc_index::bit_set::BitSet; @@ -30,24 +31,16 @@ pub fn from_mir(mir_body: &mir::Body<'_>) -> Self { // `SwitchInt` to have multiple targets to the same destination `BasicBlock`, so // de-duplication is required. This is done without reordering the successors. - let mut seen = IndexVec::from_elem(false, &bcbs); let successors = IndexVec::from_fn_n( |bcb| { - for b in seen.iter_mut() { - *b = false; - } - let bcb_data = &bcbs[bcb]; - let mut bcb_successors = Vec::new(); - for successor in bcb_filtered_successors(mir_body[bcb_data.last_bb()].terminator()) + let mut seen_bcbs = FxHashSet::default(); + let terminator = mir_body[bcbs[bcb].last_bb()].terminator(); + bcb_filtered_successors(terminator) .into_iter() .filter_map(|successor_bb| bb_to_bcb[successor_bb]) - { - if !seen[successor] { - seen[successor] = true; - bcb_successors.push(successor); - } - } - bcb_successors + // Remove duplicate successor BCBs, keeping only the first. + .filter(|&successor_bcb| seen_bcbs.insert(successor_bcb)) + .collect::>() }, bcbs.len(), );