Retain data in vectorized registers for longer

[Mark-Simulacrum]

This seems to be a mild performance improvement on the keccak crate at least, though not sure it'll show up more broadly.

[rust-highfive]

r? @jackh726

(rust-highfive has picked a reviewer for you, use r? to override)

[Mark-Simulacrum]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit 9d4c094 with merge 6ba031c17c0091086a5727f4ccee9690f10b7286...

[bors]

☀️ Try build successful - checks-actions
Build commit: 6ba031c17c0091086a5727f4ccee9690f10b7286 (6ba031c17c0091086a5727f4ccee9690f10b7286)

[rust-timer]

Queued 6ba031c17c0091086a5727f4ccee9690f10b7286 with parent a5f164f, future comparison URL.

[rust-timer]

Finished benchmarking try commit (6ba031c17c0091086a5727f4ccee9690f10b7286): comparison url.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf

[Mark-Simulacrum]

Slight, but across the board wins, I think.

[jackh726]

🤷‍♀️ neat trick, decent comment, solid (albeit small) wins

@bors r+

[bors]

📌 Commit 9d4c094 has been approved by jackh726

[bors]

⌛ Testing commit 9d4c094 with merge 45ccf91...

[bors]

☀️ Test successful - checks-actions
Approved by: jackh726
Pushing 45ccf91 to master...