Outline constant messages from panicking macros by hanna-kruppe · Pull Request #163766 · rust-lang/rust

hanna-kruppe · 2026-10-04T18:48:48Z

This emits (very slightly) less code per call site because it's passing one less argument (the implicit caller location is still passed).

Inspired by #163657

hanna-kruppe · 2026-10-04T19:07:33Z

@bors try @rust-timer queue

[EXPERIMENT] Outline some panics with constant messages

rust-bors · 2026-10-04T20:12:42Z

☀️ Try build successful (CI)
Build commit: caa37fb (caa37fb206c657fa2ce3b0adc2fe67084eaee0a8)
Base parent: f48b3e6 (f48b3e61eeece268609bd920fcca1ded047db7ca)

rust-timer · 2026-10-04T20:56:00Z

Finished benchmarking commit (caa37fb): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@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)	0.1%	[0.1%, 0.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[-0.1%, 0.1%]	2

Max RSS (memory usage)

Results (secondary 1.4%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.1%	[2.1%, 6.1%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.1%	[-4.1%, -4.1%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 0.8%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	6.7%	[6.7%, 6.7%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.1%	[-2.4%, -1.9%]	2
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.2%, secondary -0.4%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.3%, -0.2%]	11
Improvements ✅ (secondary)	-0.4%	[-0.6%, -0.2%]	13
All ❌✅ (primary)	-0.2%	[-0.3%, -0.2%]	11

Bootstrap: 490.122s -> 490.205s (0.02%)
Artifact size: 408.65 MiB -> 408.94 MiB (0.07%)

panstromek · 2026-10-05T04:34:29Z

btw. I was wondering whether we should maybe do this automatically. Either change the panic macros to output a argument-less function definition and a call, or do the equivalent in some mir opt.

[edit] oh.. lol, that's what you did 😆 I should have looked at the code before commenting

rustbot · 2026-10-10T14:23:53Z

r? @Mark-Simulacrum

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hanna-kruppe · 2026-10-10T14:26:21Z

@bors try @rust-timer queue

Outline constant messages from panicking macros

rust-bors · 2026-10-10T15:33:12Z

☀️ Try build successful (CI)
Build commit: a6a14fb (a6a14fb59886aab396ff4e72ed178520f14a5f61)
Base parent: 5ec56e3 (5ec56e3902656f2460259fc3ac0f6e2255f94417)

hanna-kruppe · 2026-10-10T19:04:43Z

That can’t be right…

panstromek · 2026-10-10T19:10:07Z

Yes, this looks like #t-compiler/performance > Suspiciously positive results (noise in get_module_children) again

ChrisDenton · 2026-10-23T18:21:57Z

r? ChrisDenton

This seems quite marginal?

panstromek · 2026-10-23T19:07:29Z

I think we should re-measure this to get real results. It seems that this benchmark noise got stable in last few days.

@bors try @rust-timer queue

Outline constant messages from panicking macros

hanna-kruppe · 2026-10-23T19:49:03Z

I’d expect the same results as on the first run (before I polished the code and extended it to todo!()): perf-neutral but a tiny win for binary size across quite a few benchmarks.

rust-bors · 2026-10-23T20:06:16Z

☀️ Try build successful (CI)
Build commit: fe83376 (fe83376e93930b5848d8e984ed3d04932072a5e2)
Base parent: e481b82 (e481b820663a10f5dad2478b2246daf73482ba82)

ChrisDenton · 2026-10-23T20:29:12Z

I’d expect the same results as on the first run (before I polished the code and extended it to todo!()): perf-neutral but a tiny win for binary size across quite a few benchmarks.

Fair enough. r=me unless the new perf results are somehow bad (though tbh in that case I'd suspecting something went wrong).

rust-timer · 2026-10-23T22:13:59Z

Finished benchmarking commit (fe83376): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@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)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.4%, -0.1%]	7
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.9%, secondary 1.8%)

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

	mean	range	count
Regressions ❌ (primary)	1.3%	[0.4%, 7.3%]	16
Regressions ❌ (secondary)	1.8%	[0.4%, 7.5%]	12
Improvements ✅ (primary)	-0.7%	[-1.1%, -0.4%]	4
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.9%	[-1.1%, 7.3%]	20

Cycles

Results (primary -0.4%, secondary 1.5%)

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

	mean	range	count
Regressions ❌ (primary)	0.8%	[0.5%, 1.1%]	4
Regressions ❌ (secondary)	5.4%	[0.4%, 17.1%]	4
Improvements ✅ (primary)	-0.8%	[-1.6%, -0.4%]	11
Improvements ✅ (secondary)	-0.7%	[-1.5%, -0.5%]	7
All ❌✅ (primary)	-0.4%	[-1.6%, 1.1%]	15

Binary size

Results (primary -0.1%, secondary -1.1%)

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

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.3%, -0.0%]	29
Improvements ✅ (secondary)	-1.1%	[-4.8%, -0.0%]	24
All ❌✅ (primary)	-0.1%	[-0.3%, -0.0%]	29

Bootstrap: 487.9s -> 486.879s (-0.21%)
Artifact size: 406.28 MiB -> 406.28 MiB (-0.00%)

ChrisDenton · 2026-10-23T22:35:36Z

@bors r+

rust-bors · 2026-10-23T22:35:39Z

📌 Commit 400b05d has been approved by ChrisDenton

It is now in the queue for this repository.

JonathanBrouwer · 2026-10-23T22:47:32Z

@bors rollup=iffy

…uwer Rollup of 5 pull requests Successful merges: - #163766 (Outline constant messages from panicking macros) - #147368 (Add extra `unchecked_disjoint_bitor` implementations.) - #164748 (Use 64-bit futex syscalls on RV32 Linux) - #164520 (powerpc: implement c-variadic correctly for softfloat targets) - #164671 (add maintainers for tier 2 riscv64 targets (baremetal only))

Rollup merge of #163766 - hanna-kruppe:outline-panic-literals, r=ChrisDenton Outline constant messages from panicking macros This emits (very slightly) less code per call site because it's passing one less argument (the implicit caller location is still passed). Inspired by #163657

…uwer Rollup of 5 pull requests Successful merges: - rust-lang/rust#163766 (Outline constant messages from panicking macros) - rust-lang/rust#147368 (Add extra `unchecked_disjoint_bitor` implementations.) - rust-lang/rust#164748 (Use 64-bit futex syscalls on RV32 Linux) - rust-lang/rust#164520 (powerpc: implement c-variadic correctly for softfloat targets) - rust-lang/rust#164671 (add maintainers for tier 2 riscv64 targets (baremetal only))

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Oct 4, 2026

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rust-bors Bot pushed a commit that referenced this pull request Oct 4, 2026

Auto merge of #163766 - hanna-kruppe:outline-panic-literals, r=<try>

caa37fb

[EXPERIMENT] Outline some panics with constant messages

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 4, 2026

hanna-kruppe force-pushed the outline-panic-literals branch 2 times, most recently from 1b49c26 to ac8f493 Compare October 10, 2026 14:22

hanna-kruppe marked this pull request as ready for review October 10, 2026 14:23

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 10, 2026

rustbot assigned Mark-Simulacrum Oct 10, 2026

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Oct 10, 2026

hanna-kruppe changed the title ~~[EXPERIMENT] Outline some panics with constant messages~~ Outline constant messages from panicking macros Oct 10, 2026

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rust-bors Bot pushed a commit that referenced this pull request Oct 10, 2026

Auto merge of #163766 - hanna-kruppe:outline-panic-literals, r=<try>

a6a14fb

Outline constant messages from panicking macros

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hanna-kruppe force-pushed the outline-panic-literals branch from ac8f493 to 61ca6bb Compare October 10, 2026 15:11

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 10, 2026

panstromek mentioned this pull request Oct 10, 2026

[experiment] put inline on GenericShunt::next to combat inlining noise #164002

Draft

fmease mentioned this pull request Oct 11, 2026

remove unnecessary char position file lookup for file!() #163865

Merged

rustbot assigned ChrisDenton and unassigned Mark-Simulacrum Oct 23, 2026

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rust-bors Bot pushed a commit that referenced this pull request Oct 23, 2026

Auto merge of #163766 - hanna-kruppe:outline-panic-literals, r=<try>

fe83376

Outline constant messages from panicking macros

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 23, 2026

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 23, 2026

JonathanBrouwer mentioned this pull request Oct 23, 2026

Rollup of 5 pull requests #164826

Merged

rust-bors Bot merged commit 9e8653b into rust-lang:main Oct 24, 2026
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rustbot added this to the 1.101.0 milestone Oct 24, 2026

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Overall result: ❌✅ regressions and improvements - no action needed

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Overall result: ✅ improvements - no action needed

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