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

[panstromek]

see: https://rust-lang.zulipchat.com/#narrow/channel/247081-t-compiler.2Fperformance/topic/Suspiciously.20positive.20results.20.28noise.20in.20get_module_children.29/with/630240582

[panstromek]

@bors try @rust-timer queue priority=-5

[rust-bors]

☀️ Try build successful (CI)
Build commit: 60bdb43 (60bdb43b84083bbfeb7feba39349b2ff313ccd14)
Base parent: 65efa19 (65efa194201c67ba29b7384255a534d61c2aa3cb)

[rust-timer]

Finished benchmarking commit (60bdb43): 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.

@bors rollup=iffy rustc-perf
@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)	-2.0%	[-3.5%, -0.4%]	2
Improvements ✅ (secondary)	-0.8%	[-3.6%, -0.1%]	5
All ❌✅ (primary)	-2.0%	[-3.5%, -0.4%]	2

Max RSS (memory usage)

Results (secondary 2.0%)

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)	2.0%	[2.0%, 2.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results (primary -3.8%, secondary -3.6%)

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)	-3.8%	[-3.8%, -3.8%]	1
Improvements ✅ (secondary)	-3.6%	[-4.7%, -2.5%]	3
All ❌✅ (primary)	-3.8%	[-3.8%, -3.8%]	1

Binary size

Results (primary -1.1%, 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)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-1.1%	[-1.1%, -1.1%]	1
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

Bootstrap: 485.904s -> 485.259s (-0.13%)
Artifact size: 406.44 MiB -> 406.54 MiB (0.02%)

[panstromek]

let's try this with a parent that we know is on the other side of the desired state.

@bors try parent=5ec56e3902656f2460259fc3ac0f6e2255f94417
@rust-timer queue priority=-6

this is a parent of #163766 (comment), which triggered the noise improvement.

[rust-bors]

☀️ Try build successful (CI)
Build commit: d9c045f (d9c045fa07a8c7c4bc2218ddd76ac4097f436d51)
Base parent: 5ec56e3 (5ec56e3902656f2460259fc3ac0f6e2255f94417)

[rust-timer]

Finished benchmarking commit (d9c045f): 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.

@bors rollup=iffy rustc-perf
@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)	-3.6%	[-3.6%, -3.6%]	1
Improvements ✅ (secondary)	-3.6%	[-3.6%, -3.6%]	1
All ❌✅ (primary)	-3.6%	[-3.6%, -3.6%]	1

Max RSS (memory usage)

Results (secondary 6.7%)

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)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results (primary 0.4%, secondary -4.2%)

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

	mean	range	count
Regressions ❌ (primary)	2.3%	[2.3%, 2.4%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.5%	[-3.5%, -3.5%]	1
Improvements ✅ (secondary)	-4.2%	[-4.2%, -4.2%]	1
All ❌✅ (primary)	0.4%	[-3.5%, 2.4%]	3

Binary size

Results (primary -1.1%, 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)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-1.1%	[-1.1%, -1.1%]	1
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

Bootstrap: 487.044s -> 487.791s (0.15%)
Artifact size: 406.45 MiB -> 406.66 MiB (0.05%)