Only enable ConstProp on opt level >= 1

[zeevm]

r? @JakobDegen

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[zeevm]

Fixes #98958

[JakobDegen]

Thanks for doing this!

Implementation looks good, only thing I'd suggest is running this on opt level 1 and above instead of 2. This is in line with what we currently do and const prop actually usually helps debug info I believe (see the ConstDebugInfo pass or whatever it's called).

r? @oli-obk as well

If you're interested in some more things to do, following up on this by doing some deduplication between the lint and non-lint versions of this pass is definitely a good next step. There's also some good opportunities around adding support for not invalidating CFG caches to VisitorMut and MirPatch - open a topic on Zulip if you're interested.

[zeevm]

Thanks Jakob, changed to opt level 1.

Will look into those 2 issues next.

[oli-obk]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

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

[bors]

⌛ Trying commit 728fb05 with merge 1099b7f9b713a844ae847af1c5268131abfa9745...

[bors]

☀️ Try build successful - checks-actions
Build commit: 1099b7f9b713a844ae847af1c5268131abfa9745 (1099b7f9b713a844ae847af1c5268131abfa9745)

[rust-timer]

Queued 1099b7f9b713a844ae847af1c5268131abfa9745 with parent f342bea, future comparison URL.

[klensy]

Current title is wrong, it should be >= 1, not == 2?

[rust-timer]

Finished benchmarking commit (1099b7f9b713a844ae847af1c5268131abfa9745): comparison url.

Instruction count

• Primary benchmarks: 😿 relevant regression found
• Secondary benchmarks: no relevant changes found

	mean1	max	count2
Regressions 😿 (primary)	0.6%	0.6%	1
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	0.6%	0.6%	1

Max RSS (memory usage)

Results

• Primary benchmarks: 🎉 relevant improvement found
• Secondary benchmarks: 🎉 relevant improvement found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-0.1%	-0.1%	1
Improvements 🎉 (secondary)	-3.2%	-3.2%	1
All 😿🎉 (primary)	-0.1%	-0.1%	1

Cycles

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

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

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-review -S-waiting-on-perf -perf-regression

Footnotes

1. the arithmetic mean of the percent change ↩ ↩²

2. number of relevant changes ↩ ↩²

[oli-obk]

@bors r+

[bors]

📌 Commit 728fb05 has been approved by oli-obk

[zeevm]

Should I squash the commits or will it happen when the PR completes?

[bjorn3]

Bors doesn't squash commits. Squashing is fine. I can re-approve it after you squash if you do it within the next 5 min or so. Otherwise keeping the commits separate is fine.

[klensy]

Should I squash the commits or will it happen when the PR completes?

There is no auto squash.

[zeevm]

Bors doesn't squash commits. Squashing is fine. I can re-approve it after you squash if you do it within the next 5 min or so. Otherwise keeping the commits separate is fine.

that's fine, I'll leave it as is.

I thought I had to squash it to complete the PR.

[bjorn3]

Once a reviewer posts an r+ comment, your PR is added to the bors queue (https://bors.rust-lang.org/queue/rust) Bors takes the first PR in the queue, merges it into a side branch and once CI passes it merges into the master branch. This ensures that CI always passes for the master branch and there are no unintended interactions between PR's that are merged close to each other.

[bors]

⌛ Testing commit 728fb05 with merge db78ab7...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing db78ab7 to master...

[rust-timer]

Finished benchmarking commit (db78ab7): comparison url.

Instruction count

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: 🎉 relevant improvements found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-1.7%	-1.9%	4
All 😿🎉 (primary)	N/A	N/A	0

Max RSS (memory usage)

Results

• Primary benchmarks: 🎉 relevant improvements found
• Secondary benchmarks: 🎉 relevant improvements found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-1.2%	-2.3%	2
Improvements 🎉 (secondary)	-3.6%	-4.2%	2
All 😿🎉 (primary)	-1.2%	-2.3%	2

Cycles

Results

• Primary benchmarks: 😿 relevant regressions found
• Secondary benchmarks: no relevant changes found

	mean1	max	count2
Regressions 😿 (primary)	2.3%	2.6%	2
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	2.3%	2.6%	2

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³