Remove no-op cleanups as post-mono MIR opt

[Mark-Simulacrum]

On cargo this cuts ~5% of the LLVM IR lines we generate (measured with -Cno-prepopulate-passes). Opening to assess performance.

[Mark-Simulacrum]

@bors2 try @rust-timer queue

[rust-bors]

⌛ Trying commit e0423d5 with merge fb9de75…

To cancel the try build, run the command @bors2 try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: fb9de75 (fb9de75a813ea747c43682b22929463ada3f80de, parent: 5e749eb66f93ee998145399fbdde337e57cd72ef)

[rust-timer]

Finished benchmarking commit (fb9de75): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@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)	18.6%	[0.2%, 60.9%]	6
Regressions ❌ (secondary)	9.4%	[0.4%, 18.4%]	2
Improvements ✅ (primary)	-1.9%	[-3.8%, -0.2%]	18
Improvements ✅ (secondary)	-2.5%	[-17.6%, -0.2%]	21
All ❌✅ (primary)	3.2%	[-3.8%, 60.9%]	24

Max RSS (memory usage)

Results (primary 8.9%, secondary 2.4%)

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

	mean	range	count
Regressions ❌ (primary)	9.2%	[1.3%, 33.3%]	34
Regressions ❌ (secondary)	3.6%	[2.9%, 4.9%]	4
Improvements ✅ (primary)	-1.6%	[-1.6%, -1.6%]	1
Improvements ✅ (secondary)	-2.4%	[-2.4%, -2.4%]	1
All ❌✅ (primary)	8.9%	[-1.6%, 33.3%]	35

Cycles

Results (primary 3.0%, 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)	29.8%	[26.6%, 33.1%]	2
Regressions ❌ (secondary)	17.1%	[17.1%, 17.1%]	1
Improvements ✅ (primary)	-1.9%	[-3.0%, -1.2%]	11
Improvements ✅ (secondary)	-6.2%	[-20.2%, -2.1%]	8
All ❌✅ (primary)	3.0%	[-3.0%, 33.1%]	13

Binary size

Results (primary -0.7%, secondary -0.9%)

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)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-0.7%	[-1.6%, -0.0%]	66
Improvements ✅ (secondary)	-0.9%	[-3.7%, -0.0%]	30
All ❌✅ (primary)	-0.7%	[-1.6%, -0.0%]	66

Bootstrap: 695.323s -> 698.39s (0.44%)
Artifact size: 371.80 MiB -> 371.90 MiB (0.03%)

[Mark-Simulacrum]

@bors2 try @rust-timer queue

[rust-bors]

Missing command.

[Mark-Simulacrum]

@bors2 try

[rust-bors]

⌛ Trying commit 676eed3 with merge e3a4b05…

To cancel the try build, run the command @bors2 try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: e3a4b05 (e3a4b05fb719511c7b8d0306c3a9e0445abcdfda, parent: f46ce66fcc3d6058f90ac5bf0930f940f1e7b0ca)

[rust-timer]

Finished benchmarking commit (e3a4b05): comparison URL.

Overall result: ✅ improvements - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

@bors rollup=never
@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)	0.4%	[0.4%, 0.4%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.0%	[-4.6%, -0.2%]	22
Improvements ✅ (secondary)	-2.8%	[-18.0%, -0.8%]	17
All ❌✅ (primary)	-1.9%	[-4.6%, 0.4%]	23

Max RSS (memory usage)

Results (primary -2.6%, secondary -1.3%)

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)	-2.6%	[-3.8%, -1.2%]	6
Improvements ✅ (secondary)	-1.3%	[-2.8%, -0.5%]	3
All ❌✅ (primary)	-2.6%	[-3.8%, -1.2%]	6

Cycles

Results (primary -2.4%, secondary -2.8%)

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

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	3.2%	[0.8%, 7.1%]	4
Improvements ✅ (primary)	-2.6%	[-4.3%, -1.2%]	22
Improvements ✅ (secondary)	-5.0%	[-20.0%, -0.5%]	11
All ❌✅ (primary)	-2.4%	[-4.3%, 1.1%]	23

Binary size

Results (primary -0.6%, 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)	-	-	0
Improvements ✅ (primary)	-0.6%	[-1.4%, -0.0%]	66
Improvements ✅ (secondary)	-0.8%	[-3.6%, -0.0%]	30
All ❌✅ (primary)	-0.6%	[-1.4%, -0.0%]	66

Bootstrap: 461.485s -> 461.37s (-0.02%)
Artifact size: 372.20 MiB -> 371.78 MiB (-0.11%)

[Mark-Simulacrum]

@bors2 try jobs=x86_64-msvc

[rust-bors]

Unknown value for argument "jobs".

[Mark-Simulacrum]

@bors2 try jobs=*x86_64-msvc*

[rust-bors]

Unknown value for argument "jobs".

[Mark-Simulacrum]

@bors2 try jobs=x86_64-msvc*

[rustbot]

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

[rust-bors]

☀️ Try build successful (CI)
Build commit: b84bb16 (b84bb16650872972b9578b4aeeb3f78acd2d8912, parent: 076a0a26fd6f4c445647a33d6daaac56f732ac05)

[petrochenkov]

r? mir-opts

[rustbot]

Failed to set assignee to mir-opts: 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.

[petrochenkov]

r? mir

[oli-obk]

@bors r+

[bors]

📌 Commit 676eed3 has been approved by oli-obk

It is now in the queue for this repository.

[cjgillot]

Is there an opportunity to reuse code from RemoveNoopLandingPads MIR pass?

[RalfJung]

Given that comments and variable names don't line up, seems better to
@bors r-

[Mark-Simulacrum]

@bors2 try @rust-timer queue

This is essentially a re-write with @cjgillot's excellent suggestion to reuse the analysis in RemoveNoopLandingPads. Also adjusted some of the naming per @RalfJung's comments -- I'm not perfectly happy with the names, some of this is sort of quasi-true (e.g., reachable is only accurate if you apply the right filters while you traverse the MIR, since we currently can't edit it in-place).

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[rust-bors]

⌛ Trying commit c04a255 with merge d12ed3f…

To cancel the try build, run the command @bors2 try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: d12ed3f (d12ed3fc0cb645af2b945d13048aba82f574ee91, parent: 6677875279b560442a07a08d5119b4cd6b3c5593)

[rust-timer]

Queued d12ed3f with parent 6677875, future comparison URL.
There are currently 14 preceding artifacts in the queue.
It will probably take at least ~14.2 hours until the benchmark run finishes.