Add 2026-05-12 triage

triage/2026/2026-05-12.md

@@ -0,0 +1,145 @@
+# 2026-05-12 Triage Log
+
+This week saw a couple of PRs affecting the new trait solver, which is steadily moving forward,
+in particular [#156139](https://github.com/rust-lang/rust/pull/156139) was a massive perf. win.
+[#156185](https://github.com/rust-lang/rust/pull/156185) optimized visibility computation, resulting
+in up to a 8% win on the `typenum` crate.
+
+Triage done by **@Kobzol**.
+Revision range: [1d72d7e8..aa31d6d8](https://perf.rust-lang.org/?start=1d72d7e8136faaebad3a85eeed432e6ea1b2ffab&end=aa31d6d8020dcb7c6e6635648d1ca2bc18caf059&absolute=false&stat=instructions%3Au)
+
+**Summary**:
+
+| (instructions:u)                   | mean   | range           | count |
+|:----------------------------------:|:------:|:---------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.3%   | [0.1%, 0.4%]    | 62    |
+| Regressions ❌ <br /> (secondary)  | 0.5%   | [0.1%, 1.5%]    | 77    |
+| Improvements ✅ <br /> (primary)   | -1.7%  | [-8.8%, -0.2%]  | 18    |
+| Improvements ✅ <br /> (secondary) | -13.6% | [-85.6%, -0.0%] | 34    |
+| All ❌✅ (primary)                 | -0.2%  | [-8.8%, 0.4%]   | 80    |
+
+
+2 Regressions, 2 Improvements, 5 Mixed; 4 of them in rollups
+31 artifact comparisons made in total
+
+#### Regressions
+
+Lint unused pub items in binary crates [#149509](https://github.com/rust-lang/rust/pull/149509) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=4ddd4538a881317c622ed674b08300b8fc8dabdd&end=0e5924a4a0b57f2c6bc8cac93f59281e68541a91&stat=instructions:u)
+
+| (instructions:u)                   | mean | range        | count |
+|:----------------------------------:|:----:|:------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.3% | [0.1%, 0.4%] | 4     |
+| Regressions ❌ <br /> (secondary)  | 0.1% | [0.1%, 0.1%] | 1     |
+| Improvements ✅ <br /> (primary)   | -    | -            | 0     |
+| Improvements ✅ <br /> (secondary) | -    | -            | 0     |
+| All ❌✅ (primary)                 | 0.3% | [0.1%, 0.4%] | 4     |
+
+- The regression looks genuine, but it is very small. The compiler now runs a new allow-by-default lint, so that is expected.
+- Marked as triaged.
+
+@rustbot label: +perf-regression-triaged
+
+-Zassumptions-on-binders [#155887](https://github.com/rust-lang/rust/pull/155887) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=aa31d6d8020dcb7c6e6635648d1ca2bc18caf059&end=29b7590130c83542a095cdf1323ed0f78eec2bb8&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2%  | [0.1%, 0.2%]   | 10    |
+| Regressions ❌ <br /> (secondary)  | 0.5%  | [0.1%, 1.1%]   | 25    |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.0% | [-0.0%, -0.0%] | 1     |
+| All ❌✅ (primary)                 | 0.2%  | [0.1%, 0.2%]   | 10    |
+
+- Tiny regressions across the board, mostly in trait-heavy crates and the new trait solver.
+- Not marking as triaged yet.
+
+#### Improvements
+
+Rollup of 12 pull requests [#156267](https://github.com/rust-lang/rust/pull/156267) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=0e5924a4a0b57f2c6bc8cac93f59281e68541a91&end=32bd660612bf1c61bdf290a3ec643c8538b8357d&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -0.3% | [-0.3%, -0.2%] | 8     |
+| Improvements ✅ <br /> (secondary) | -0.2% | [-0.2%, -0.2%] | 2     |
+| All ❌✅ (primary)                 | -0.3% | [-0.3%, -0.2%] | 8     |
+
+
+resolve: Evaluate private visibilities eagerly in eff vis computation [#156185](https://github.com/rust-lang/rust/pull/156185) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d1961bebe091816d8ce9771f29ad471dda398f5d&end=99eed207b47aca1fec5c665531db8e948a92d0ca&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | -     | -              | 0     |
+| Improvements ✅ <br /> (primary)   | -2.5% | [-8.6%, -0.2%] | 11    |
+| Improvements ✅ <br /> (secondary) | -1.8% | [-2.5%, -0.3%] | 13    |
+| All ❌✅ (primary)                 | -2.5% | [-8.6%, -0.2%] | 11    |
+
+
+#### Mixed
+
+Short-circuit `calculate_fallback_to_f32` when no float vars [#156139](https://github.com/rust-lang/rust/pull/156139) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=1d72d7e8136faaebad3a85eeed432e6ea1b2ffab&end=cb40c25f6aebb637163d26bf76a680ed6e5d1eda&stat=instructions:u)
+
+| (instructions:u)                   | mean   | range           | count |
+|:----------------------------------:|:------:|:---------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -      | -               | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.1%   | [0.0%, 0.1%]    | 4     |
+| Improvements ✅ <br /> (primary)   | -      | -               | 0     |
+| Improvements ✅ <br /> (secondary) | -21.0% | [-87.6%, -0.0%] | 18    |
+| All ❌✅ (primary)                 | -      | -               | 0     |
+
+- Massive wins in the new trait solver.
+- Already marked as triaged.
+
+Rollup of 7 pull requests [#156190](https://github.com/rust-lang/rust/pull/156190) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=740679e1f5554a3c1695317e084809e3fceb9825&end=e95e73209faf6ead2bc5c7636e45e589a751b79b&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.2%  | [0.1%, 0.3%]   | 3     |
+| Regressions ❌ <br /> (secondary)  | 0.5%  | [0.2%, 0.7%]   | 25    |
+| Improvements ✅ <br /> (primary)   | -0.3% | [-0.3%, -0.3%] | 1     |
+| Improvements ✅ <br /> (secondary) | -1.2% | [-1.8%, -0.5%] | 2     |
+| All ❌✅ (primary)                 | 0.1%  | [-0.3%, 0.3%]  | 4     |
+
+- Regression caused by [#156172](https://github.com/rust-lang/rust/pull/156172), discussion is continuing there.
+- Marked as triaged.
+
+Rollup of 15 pull requests [#156217](https://github.com/rust-lang/rust/pull/156217) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=e95e73209faf6ead2bc5c7636e45e589a751b79b&end=ba1a955819d72439dc59d5f73ad7a6a01e3fcdfe&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -              | 0     |
+| Regressions ❌ <br /> (secondary)  | 0.6%  | [0.1%, 1.0%]   | 10    |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -0.0% | [-0.1%, -0.0%] | 3     |
+| All ❌✅ (primary)                 | -     | -              | 0     |
+
+- The wg-grammar regression was caused by [#155808](https://github.com/rust-lang/rust/pull/155808).
+- Marked as triaged.
+
+Improve caching by introducing `TypingMode::ErasedNotCoherence` [#155443](https://github.com/rust-lang/rust/pull/155443) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=ba1a955819d72439dc59d5f73ad7a6a01e3fcdfe&end=365c0e1d7a614ca94cb48431dcd2bc6d3b645db1&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range           | count |
+|:----------------------------------:|:-----:|:---------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | -     | -               | 0     |
+| Regressions ❌ <br /> (secondary)  | 2.5%  | [0.0%, 16.6%]   | 18    |
+| Improvements ✅ <br /> (primary)   | -     | -               | 0     |
+| Improvements ✅ <br /> (secondary) | -9.0% | [-26.2%, -0.1%] | 11    |
+| All ❌✅ (primary)                 | -     | -               | 0     |
+
+- This only really affects the new solver, where it is a big win for `wg-grammar`, though also a big regression for `deeply-nested-multi`.
+- Marked as triaged.
+@rustbot label: +perf-regression-triaged
+
+Rollup of 4 pull requests [#156324](https://github.com/rust-lang/rust/pull/156324) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f2b291d902bfde7d7f209fc3a64908134bcef201&end=8068e2fc9afa8c888336b12db01987be768785f9&stat=instructions:u)
+
+| (instructions:u)                   | mean  | range          | count |
+|:----------------------------------:|:-----:|:--------------:|:-----:|
+| Regressions ❌ <br /> (primary)    | 0.3%  | [0.3%, 0.3%]   | 1     |
+| Regressions ❌ <br /> (secondary)  | 0.3%  | [0.2%, 0.3%]   | 3     |
+| Improvements ✅ <br /> (primary)   | -     | -              | 0     |
+| Improvements ✅ <br /> (secondary) | -1.5% | [-1.5%, -1.5%] | 1     |
+| All ❌✅ (primary)                 | 0.3%  | [0.3%, 0.3%]   | 1     |
+
+- Tiny regression on hyper `doc` benchmark and the `bitmaps` benchmark with the new trait solver, overall a wash. I don't think it's worth digging further.
+- Marked as triaged.