Shrink Nonterminal

[nnethercote]

These commits shrink Nonterminal from 240 bytes to 40 bytes. When building serde_derive they reduce the number of memcpy calls from 9.6M to 7.4M, and it's a tiny win on a few other benchmarks.

r? @petrochenkov

[nnethercote]

Notable local check-clean results:

serde-serde_derive-check
        avg: -0.8%      min: -0.8%      max: -0.8%
coercions-check
        avg: -0.4%?     min: -0.4%?     max: -0.4%?
deep-vector-check
        avg: -0.3%      min: -0.3%      max: -0.3%
tuple-stress-check
        avg: 0.2%       min: 0.2%       max: 0.2%
helloworld-check
        avg: -0.1%      min: -0.1%      max: -0.1%
issue-46449-check
        avg: -0.1%      min: -0.1%      max: -0.1%
unify-linearly-check
        avg: -0.1%      min: -0.1%      max: -0.1%
syn-check
        avg: -0.1%      min: -0.1%      max: -0.1%
unicode_normalization-check
        avg: 0.1%       min: 0.1%       max: 0.1%
await-call-tree-check
        avg: -0.1%      min: -0.1%      max: -0.1%
tokio-webpush-simple-check
        avg: -0.1%      min: -0.1%      max: -0.1%

Note that serde_derive is not part of rustc-perf, but I have included it in my local copy to get the above results.

[Centril]

Would appreciate if we could block merging this PR on first merging #67131 since this one will generate a lot of conflicts with that PR.

[Centril]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion

[bors]

⌛ Trying commit ed9ba9b with merge 23f3174...

[bors]

☀️ Try build successful - checks-azure
Build commit: 23f3174 (23f3174f3dafe415f12b9c931d59df4853cadedd)

[rust-timer]

Queued 23f3174 with parent a605441, future comparison URL.

[rust-timer]

Finished benchmarking try commit 23f3174, comparison URL.

[nnethercote]

Here are the serde_derive results, for comparison:

serde-serde_derive-check
- avg: -1.1%  min: -1.8%  max: -0.7% 
- clean                 11,770,595,200.00  11,668,371,819.00  -0.9% 
- baseline incremental  14,431,966,930.00  14,328,177,470.00  -0.7% 
- clean incremental      5,746,154,634.00   5,642,802,601.00  -1.8% 

[petrochenkov]

r=me after rebase

[joelpalmer]

Ping from Triage: Any updates @nnethercote?

[nnethercote]

Back now from PTO, I have rebased.

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion

[bors]

⌛ Trying commit 7d2173e with merge 1941303dc808ee27858ab3d907f612c9ab9c972d...

[bors]

☀️ Try build successful - checks-azure
Build commit: 1941303dc808ee27858ab3d907f612c9ab9c972d (1941303dc808ee27858ab3d907f612c9ab9c972d)

[rust-timer]

Queued 1941303dc808ee27858ab3d907f612c9ab9c972d with parent 9ed29b6, future comparison URL.

[nnethercote]

rust-timer didn't give us a "finished" message, but the results are in and look as expected -- a small win.

r? @petrochenkov

[petrochenkov]

@bors r+

[bors]

📌 Commit 7d2173e has been approved by petrochenkov

[bors]

⌛ Testing commit 7d2173e with merge b1cb3c0...

[bors]

☀️ Test successful - checks-azure
Approved by: petrochenkov
Pushing b1cb3c0 to master...

[rust-highfive]

📣 Toolstate changed by #67340!

Tested on commit b1cb3c0.
Direct link to PR: #67340

🎉 rustc-guide on linux: test-fail → test-pass (cc @JohnTitor @amanjeev @spastorino @mark-i-m, @rust-lang/infra).