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| author | Alex Crichton <alex@alexcrichton.com> | 2017-09-16 09:16:55 -0500 |
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| committer | Alex Crichton <alex@alexcrichton.com> | 2017-09-16 17:09:40 -0700 |
| commit | 3dbd9c5489702442831d5600c6aacd27159984d4 (patch) | |
| tree | 55bd59ed9fc35597d1f1b5ab99adc7d30bf6d600 /src/test/incremental/thinlto | |
| parent | c25290d7150ef5be75edf00420f25cbad2280f0f (diff) | |
| parent | 351f56a6034486c38c3b36bfbbd15a81a39ba9aa (diff) | |
| download | rust-3dbd9c5489702442831d5600c6aacd27159984d4.tar.gz rust-3dbd9c5489702442831d5600c6aacd27159984d4.zip | |
Rollup merge of #44577 - cuviper:flat_map-fold, r=alexcrichton
Customize `<FlatMap as Iterator>::fold`
`FlatMap` can use internal iteration for its `fold`, which shows a
performance advantage in the new benchmarks:
test iter::bench_flat_map_chain_ref_sum ... bench: 4,354,111 ns/iter (+/- 108,871)
test iter::bench_flat_map_chain_sum ... bench: 468,167 ns/iter (+/- 2,274)
test iter::bench_flat_map_ref_sum ... bench: 449,616 ns/iter (+/- 6,257)
test iter::bench_flat_map_sum ... bench: 348,010 ns/iter (+/- 1,227)
... where the "ref" benches are using `by_ref()` that isn't optimized.
So this change shows a decent advantage on its own, but much more when
combined with a `chain` iterator that also optimizes `fold`.
Diffstat (limited to 'src/test/incremental/thinlto')
0 files changed, 0 insertions, 0 deletions