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coverage: Extract subtracted_sum in counter creation

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This commit is contained in:
Zalathar 2024-10-16 21:25:09 +11:00
parent 3b382642ab
commit 2a3b4a0afd
2 changed files with 14 additions and 12 deletions
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16
compiler/rustc_mir_transform/src/coverage/counters.rs
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@ -182,6 +182,12 @@ impl CoverageCounters {
.reduce(|accum, counter| self.make_expression(accum, Op::Add, counter))
}
/// Creates a counter whose value is `lhs - SUM(rhs)`.
fn make_subtracted_sum(&mut self, lhs: BcbCounter, rhs: &[BcbCounter]) -> BcbCounter {
let Some(rhs_sum) = self.make_sum(rhs) else { return lhs };
self.make_expression(lhs, Op::Subtract, rhs_sum)
}
pub(super) fn num_counters(&self) -> usize {
self.counter_increment_sites.len()
}
@ -338,8 +344,7 @@ impl<'a> CountersBuilder<'a> {
};
// For each out-edge other than the one that was chosen to get an expression,
// ensure that it has a counter (existing counter/expression or a new counter),
// and accumulate the corresponding counters into a single sum expression.
// ensure that it has a counter (existing counter/expression or a new counter).
let other_out_edge_counters = successors
.iter()
.copied()
@ -347,15 +352,10 @@ impl<'a> CountersBuilder<'a> {
.filter(|&edge_target_bcb| edge_target_bcb != target_bcb)
.map(|to_bcb| self.get_or_make_edge_counter(from_bcb, to_bcb))
.collect::<Vec<_>>();
let Some(sum_of_all_other_out_edges) = self.counters.make_sum(&other_out_edge_counters)
else {
return;
};
// Now create an expression for the chosen edge, by taking the counter
// for its source node and subtracting the sum of its sibling out-edges.
let expression =
self.counters.make_expression(node_counter, Op::Subtract, sum_of_all_other_out_edges);
let expression = self.counters.make_subtracted_sum(node_counter, &other_out_edge_counters);
debug!("{target_bcb:?} gets an expression: {expression:?}");
self.counters.set_edge_counter(from_bcb, target_bcb, expression);