Improve PadAdapter::write_char

[a1phyr]

Split from #108043

[rustbot]

r? @joshtriplett

(rustbot has picked a reviewer for you, use r? to override)

[dtolnay]

Per #108043 (comment):
@bors try @rust-timer queue

[bors]

⌛ Trying commit 814f4f6 with merge 1efdb58...

[bors]

☀️ Try build successful - checks-actions
Build commit: 1efdb58 (1efdb58c9f001ce64a4416bba0852254af220412)

[rust-timer]

Finished benchmarking commit (1efdb58): 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)	0.3%	[0.3%, 0.3%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.2%	[2.1%, 2.3%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

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: 632.183s -> 634.704s (0.40%)
Artifact size: 318.14 MiB -> 318.19 MiB (0.01%)

[dtolnay]

@bors r+

[bors]

📌 Commit 814f4f6 has been approved by dtolnay

It is now in the queue for this repository.

[bors]

⌛ Testing commit 814f4f6 with merge 3ae41aa...

[rust-log-analyzer]

The job aarch64-gnu failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

   Compiling addr2line v0.21.0
[RUSTC-TIMING] addr2line test:false 0.546
[RUSTC-TIMING] gimli test:false 4.861
[RUSTC-TIMING] object test:false 5.632
##[error]The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.
##[group]Clock drift check
  local time: Sun Sep 17 00:01:51 UTC 2023
  network time: Sun, 17 Sep 2023 00:01:51 GMT
##[endgroup]
##[endgroup]
Session terminated, killing shell... ...killed.
##[error]The operation was canceled.

[bors]

💔 Test failed - checks-actions

[dtolnay]

Can't tell what failed.
@bors retry

[bors]

⌛ Testing commit 814f4f6 with merge a09c1f8...

[bors]

☀️ Test successful - checks-actions
Approved by: dtolnay
Pushing a09c1f8 to master...

[rust-timer]

Finished benchmarking commit (a09c1f8): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

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

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.7%	[-3.1%, -2.3%]	2
Improvements ✅ (secondary)	-2.6%	[-3.6%, -0.8%]	4
All ❌✅ (primary)	-2.7%	[-3.1%, -2.3%]	2

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: 635.152s -> 635.86s (0.11%)
Artifact size: 318.44 MiB -> 318.46 MiB (0.00%)