Consolidate panicking functions in `slice/index.rs` #145137

Kmeakin · 2025-08-08T22:53:52Z

Consolidate all the panicking functions in slice/index.rs to use a single slice_index_fail function, similar to how it is done in str/traits.rs.

Split off from #145024

rustbot · 2025-08-08T22:53:57Z

r? @jhpratt

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rustbot · 2025-08-09T00:06:48Z

The Miri subtree was changed

cc @rust-lang/miri

xizheyin · 2025-08-09T03:32:10Z

Thanks for the code. You could try ./x test codegen-llvm to test it locally first.
https://rustc-dev-guide.rust-lang.org/tests/intro.html

Kmeakin · 2025-08-10T22:59:36Z

@bors try @rust-timer queue

rust-bors · 2025-08-10T22:59:38Z

@Kmeakin: 🔑 Insufficient privileges: not in try users

jhpratt · 2025-08-11T18:42:19Z

I'm not convinced that this is an improvement, but on the other hand optimizations are weird.

@bors2 try @rust-timer queue

…<try> Consolidate panicking functions in `slice/index.rs`

rust-bors · 2025-08-11T20:58:19Z

☀️ Try build successful (CI)
Build commit: fa10c86 (fa10c86b130152ce0be5ff020bd92275c432f6b5, parent: fce0e74720d199eb7839fdb51af35ac5226da178)

rust-timer · 2025-08-12T00:58:31Z

Finished benchmarking commit (fa10c86): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	1.0%	[1.0%, 1.0%]	1
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-0.7%	[-1.2%, -0.3%]	5
Improvements ✅ (secondary)	-0.2%	[-0.3%, -0.1%]	2
All ❌✅ (primary)	-0.5%	[-1.2%, 1.0%]	6

Max RSS (memory usage)

Results (primary 1.6%, secondary -2.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	3.0%	[1.1%, 4.9%]	4
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-3.8%	[-3.8%, -3.8%]	1
Improvements ✅ (secondary)	-3.7%	[-4.5%, -2.5%]	4
All ❌✅ (primary)	1.6%	[-3.8%, 4.9%]	5

Cycles

Results (primary 2.6%, secondary 3.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.6%	[2.6%, 2.6%]	1
Regressions ❌ (secondary)	4.6%	[2.4%, 6.6%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	2.6%	[2.6%, 2.6%]	1

Binary size

Results (primary -0.1%, secondary -0.2%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.4%]	13
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	2
Improvements ✅ (primary)	-0.2%	[-0.4%, -0.0%]	33
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.0%]	41
All ❌✅ (primary)	-0.1%	[-0.4%, 0.4%]	46

Bootstrap: 464.993s -> 463.159s (-0.39%)
Artifact size: 377.36 MiB -> 377.58 MiB (0.06%)

bors · 2025-08-20T20:30:54Z

📌 Commit 7d5c9ca has been approved by jhpratt

It is now in the queue for this repository.

…nicking, r=jhpratt Consolidate panicking functions in `slice/index.rs` Consolidate all the panicking functions in `slice/index.rs` to use a single `slice_index_fail` function, similar to how it is done in `str/traits.rs`. Split off from rust-lang#145024

Rollup of 14 pull requests Successful merges: - #143383 (stabilize `const_array_each_ref`) - #144443 (Make target pointer width in target json an integer) - #144758 ([Doc] Add links to the various collections) - #144915 (Defer tail call ret ty equality to check_tail_calls) - #145137 (Consolidate panicking functions in `slice/index.rs`) - #145256 (Add new `--test-codegen-backend` bootstrap option) - #145297 (fix(debuginfo): handle false positives in overflow check) - #145415 (std_detect: RISC-V: implement implication to "C") - #145642 (Do not use effective_visibilities query for Adt types of a local trait while proving a where-clause) - #145650 (Fix JS search scripts path) - #145654 (Download CI GCC into the correct directory) - #145662 (Enforce correct number of arguments for `"x86-interrupt"` functions) - #145674 (Enable triagebot `[review-changes-since]` feature) - #145678 (Fix typo in docstring) r? `@ghost` `@rustbot` modify labels: rollup

…nicking, r=jhpratt Consolidate panicking functions in `slice/index.rs` Consolidate all the panicking functions in `slice/index.rs` to use a single `slice_index_fail` function, similar to how it is done in `str/traits.rs`. Split off from rust-lang#145024

Rollup of 15 pull requests Successful merges: - #143383 (stabilize `const_array_each_ref`) - #144758 ([Doc] Add links to the various collections) - #144915 (Defer tail call ret ty equality to check_tail_calls) - #145137 (Consolidate panicking functions in `slice/index.rs`) - #145256 (Add new `--test-codegen-backend` bootstrap option) - #145297 (fix(debuginfo): handle false positives in overflow check) - #145415 (std_detect: RISC-V: implement implication to "C") - #145590 (Prevent impossible combinations in `ast::ModKind`.) - #145621 (Fix some doc typos) - #145642 (Do not use effective_visibilities query for Adt types of a local trait while proving a where-clause) - #145650 (Fix JS search scripts path) - #145654 (Download CI GCC into the correct directory) - #145662 (Enforce correct number of arguments for `"x86-interrupt"` functions) - #145674 (Enable triagebot `[review-changes-since]` feature) - #145678 (Fix typo in docstring) r? `@ghost` `@rustbot` modify labels: rollup

jhpratt · 2025-08-21T03:51:04Z

@bors r- #145691 (comment)

mir-opt codegen needs blessing

Consolidate all the panicking functions in `slice/index.rs` to use a single `slice_index_fail` function, similar to how it is done in `str/traits.rs`.

rustbot · 2025-08-21T10:15:38Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

Kmeakin · 2025-08-21T11:34:22Z

@rustbot ready

jhpratt · 2025-08-21T20:31:04Z

@bors r+

bors · 2025-08-21T20:31:06Z

📌 Commit 377a0c8 has been approved by jhpratt

It is now in the queue for this repository.

Rollup of 16 pull requests Successful merges: - #137494 (libstd: init(): dup() subsequent /dev/nulls instead of opening them again) - #144541 (c-variadic: multiple ABIs in the same program for arm) - #144613 (aarch64-nintendo-switch-freestanding - Enable CPU features that are always available in a live system (crypto instructions, plus explicit NEON).) - #144780 (Add a method to dump MIR in the middle of MIR building) - #145137 (Consolidate panicking functions in `slice/index.rs`) - #145507 (Refactor attribute parsing to improve ergonomics and some diagnostics) - #145604 (Gate static closures behind a parser feature) - #145648 (Add two tidy dependency checks) - #145661 (update some s390x codegen tests) - #145672 (Instantiate higher-ranked binder with erased when checking `IntoIterator` predicate for query instability) - #145689 (Migrate `panic_unwind` to use `cfg_select!`) - #145700 (Handle `ReEarlyParam` in `type_name`.) - #145703 (Remove MIPS targets from CI LLVM platforms) - #145704 (ci: don't cleanup windows disk) - #145705 (remove an `as` cast in prefetch codegen) - #145712 (Update outdated link in bound region comments) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #145137 - Kmeakin:km/optimize-slice-index-panicking, r=jhpratt Consolidate panicking functions in `slice/index.rs` Consolidate all the panicking functions in `slice/index.rs` to use a single `slice_index_fail` function, similar to how it is done in `str/traits.rs`. Split off from #145024

Rollup of 16 pull requests Successful merges: - rust-lang/rust#137494 (libstd: init(): dup() subsequent /dev/nulls instead of opening them again) - rust-lang/rust#144541 (c-variadic: multiple ABIs in the same program for arm) - rust-lang/rust#144613 (aarch64-nintendo-switch-freestanding - Enable CPU features that are always available in a live system (crypto instructions, plus explicit NEON).) - rust-lang/rust#144780 (Add a method to dump MIR in the middle of MIR building) - rust-lang/rust#145137 (Consolidate panicking functions in `slice/index.rs`) - rust-lang/rust#145507 (Refactor attribute parsing to improve ergonomics and some diagnostics) - rust-lang/rust#145604 (Gate static closures behind a parser feature) - rust-lang/rust#145648 (Add two tidy dependency checks) - rust-lang/rust#145661 (update some s390x codegen tests) - rust-lang/rust#145672 (Instantiate higher-ranked binder with erased when checking `IntoIterator` predicate for query instability) - rust-lang/rust#145689 (Migrate `panic_unwind` to use `cfg_select!`) - rust-lang/rust#145700 (Handle `ReEarlyParam` in `type_name`.) - rust-lang/rust#145703 (Remove MIPS targets from CI LLVM platforms) - rust-lang/rust#145704 (ci: don't cleanup windows disk) - rust-lang/rust#145705 (remove an `as` cast in prefetch codegen) - rust-lang/rust#145712 (Update outdated link in bound region comments) r? `@ghost` `@rustbot` modify labels: rollup

…nicking, r=jhpratt Consolidate panicking functions in `slice/index.rs` Consolidate all the panicking functions in `slice/index.rs` to use a single `slice_index_fail` function, similar to how it is done in `str/traits.rs`. Split off from rust-lang#145024

rustbot assigned jhpratt Aug 8, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Aug 8, 2025

Kmeakin mentioned this pull request Aug 8, 2025

Optimize indexing slices and strs with inclusive ranges #145024

Open