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coverage: Extract CoverageGraph::bcb_has_multiple_in_edges

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This was previously a helper method in `MakeBcbCounters`, but putting it in the
graph lets us call it from `BcbBranch`, and gives us a more fine-grained
borrow.
This commit is contained in:
Zalathar 2023-10-30 20:54:19 +11:00
parent a1e2c10b1f
commit 276a32994e
2 changed files with 16 additions and 9 deletions
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16
compiler/rustc_mir_transform/src/coverage/graph.rs
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@ -199,6 +199,20 @@ impl CoverageGraph {
pub fn cmp_in_dominator_order(&self, a: BasicCoverageBlock, b: BasicCoverageBlock) -> Ordering {
self.dominators.as_ref().unwrap().cmp_in_dominator_order(a, b)
}
/// Returns true if the given node has 2 or more in-edges, i.e. 2 or more
/// predecessors.
///
/// This property is interesting to code that assigns counters to nodes and
/// edges, because if a node _doesn't_ have multiple in-edges, then there's
/// no benefit in having a separate counter for its in-edge, because it
/// would have the same value as the node's own counter.
///
/// FIXME: That assumption might not be true for [`TerminatorKind::Yield`]?
#[inline(always)]
pub(super) fn bcb_has_multiple_in_edges(&self, bcb: BasicCoverageBlock) -> bool {
self.predecessors[bcb].len() > 1
}
}
impl Index<BasicCoverageBlock> for CoverageGraph {
@ -335,7 +349,7 @@ impl BcbBranch {
to_bcb: BasicCoverageBlock,
basic_coverage_blocks: &CoverageGraph,
) -> Self {
let edge_from_bcb = if basic_coverage_blocks.predecessors[to_bcb].len() > 1 {
let edge_from_bcb = if basic_coverage_blocks.bcb_has_multiple_in_edges(from_bcb) {
Some(from_bcb)
} else {
None