EXPERIMENT: Use rust-cold for reserve_for_push

[scottmcm]

This is probably bad, since it means reserve_for_push ends up needing to save all the xmm* registers, but it also reduces register pressure in the code calling push, so it'll depend on what the balance is between reallocating pushes and existing-capacity pushes.

This cc blocks inlining, but the function is already inline(never).

r? @ghost

[scottmcm]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 3e838b3 with merge 0d9872c10177e97b14fa2a422e5bdab1543e21b8...

[bors]

☀️ Try build successful - checks-actions
Build commit: 0d9872c10177e97b14fa2a422e5bdab1543e21b8 (0d9872c10177e97b14fa2a422e5bdab1543e21b8)

[rust-timer]

Finished benchmarking commit (0d9872c10177e97b14fa2a422e5bdab1543e21b8): comparison URL.

Overall result: ❌✅ regressions and improvements - 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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@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)	0.5%	[0.2%, 0.9%]	62
Regressions ❌ (secondary)	0.6%	[0.3%, 1.0%]	20
Improvements ✅ (primary)	-0.4%	[-0.5%, -0.4%]	3
Improvements ✅ (secondary)	-0.7%	[-1.0%, -0.5%]	8
All ❌✅ (primary)	0.5%	[-0.5%, 0.9%]	65

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)	2.6%	[2.3%, 2.9%]	2
Regressions ❌ (secondary)	2.6%	[1.5%, 3.8%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.1%	[-1.3%, -1.0%]	3
All ❌✅ (primary)	2.6%	[2.3%, 2.9%]	2

Cycles

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

Binary size

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)	0.0%	[0.0%, 0.1%]	40
Regressions ❌ (secondary)	0.4%	[0.0%, 1.3%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.1%]	40

Bootstrap: 631.198s -> 632.2s (0.16%)
Artifact size: 316.03 MiB -> 316.31 MiB (0.09%)