Prefer not to early return from derived visitables

[eggyal]

LLVM is not able to tail-call optimise the final early return, as there instructions that follow it. Making that call the returned expression resolves this. (As identified in #117896 (comment)).

r? wg-compiler-performance

[rustbot]

Failed to set assignee to tgnottingham: invalid assignee

Note: Only org members with at least the repository "read" role, users with write permissions, or people who have commented on the PR may be assigned.

[eggyal]

Hm. Maybe it's not correct to seek review from the wg.

Not sure who to request instead. r? types

[lqd]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 1fa6e5b with merge 4c24faf...

[bors]

☀️ Try build successful - checks-actions
Build commit: 4c24faf (4c24faf0a8c709baf83bca3e381b6d1463695e03)

[lqd]

@rust-timer build 4c24faf

[rust-timer]

Finished benchmarking commit (4c24faf): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.5%	[0.4%, 0.9%]	7
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.2%]	1
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 670.936s -> 671.766s (0.12%)
Artifact size: 315.45 MiB -> 315.40 MiB (-0.02%)

[lcnr]

the perf results seem slightly negative. Do you still want to merge this?

[eggyal]

Let me investigate - had seen quite different results locally, albeit there were other variables at play too. I'll try to isolate them and figure it out!

@rustbot author