StateTransform: Only load pin field once.

[cjgillot]

The current implementation starts by transforming all instances of _1 into (*_1), and then traverses the body again to transform (*_1) into (*(_1.0)), and again for Derefer.

This PR changes the implementation to only traverse the body once. As _1.0 cannot be not modified inside the body (we just changed its type!), we have no risk of loading from the wrong pointer.

[rustbot]

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[rustbot]

r? @BoxyUwU

rustbot has assigned @BoxyUwU.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[cjgillot]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 8a45031 (8a45031b817c65c13e267ee4f0c1aa833399b480, parent: 7a52736039856a3626eefec32d80c9df900b7afd)

[rust-timer]

Finished benchmarking commit (8a45031): 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)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.9%	[-1.9%, -0.2%]	16
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -5.2%)

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
Improvements ✅ (secondary)	-5.2%	[-5.2%, -5.2%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary 0.3%)

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)	1.9%	[1.5%, 2.4%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-2.9%, -2.9%]	1
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.0%, secondary -1.8%)

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)	-0.0%	[-0.1%, -0.0%]	7
Improvements ✅ (secondary)	-1.8%	[-6.0%, -0.2%]	12
All ❌✅ (primary)	-0.0%	[-0.1%, -0.0%]	7

Bootstrap: 472.232s -> 472.472s (0.05%)
Artifact size: 388.41 MiB -> 388.41 MiB (-0.00%)

[bors]

☔ The latest upstream changes (presumably #145513) made this pull request unmergeable. Please resolve the merge conflicts.

[bors]

☔ The latest upstream changes (presumably #147640) made this pull request unmergeable. Please resolve the merge conflicts.

[BoxyUwU]

r? compiler

[jdonszelmann]

r? compiler

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[oli-obk]

r? @oli-obk

@bors r+

[bors]

📌 Commit ed85b96 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit ed85b96 with merge 79966ae...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 79966ae to master...

[github-actions]

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 04ff05c (parent) -> 79966ae (this PR)

Test differences

Show 4 test diffs

4 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 79966ae420f38c5861d177356a3446023c090d6d --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

1. dist-aarch64-apple: 6067.0s -> 7416.2s (22.2%)
2. dist-apple-various: 3295.5s -> 3767.4s (14.3%)
3. aarch64-apple: 7356.4s -> 8324.3s (13.2%)
4. x86_64-msvc-1: 9290.1s -> 8157.3s (-12.2%)
5. pr-check-1: 1435.8s -> 1573.5s (9.6%)
6. x86_64-gnu-llvm-20-3: 5710.6s -> 6232.1s (9.1%)
7. dist-aarch64-windows-gnullvm: 5015.8s -> 4584.2s (-8.6%)
8. dist-various-1: 3950.8s -> 3628.1s (-8.2%)
9. aarch64-gnu-llvm-20-1: 3630.5s -> 3409.5s (-6.1%)
10. dist-arm-linux-gnueabi: 4736.4s -> 5021.9s (6.0%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

[rust-timer]

Finished benchmarking commit (79966ae): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -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)	-	-	0
Improvements ✅ (secondary)	-0.9%	[-1.9%, -0.3%]	15
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary -0.3%, 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)	3.6%	[3.6%, 3.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.3%	[-2.4%, -2.1%]	2
Improvements ✅ (secondary)	-1.1%	[-1.1%, -1.1%]	1
All ❌✅ (primary)	-0.3%	[-2.4%, 3.6%]	3

Cycles

Results (secondary -3.3%)

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)	-	-	0
Improvements ✅ (secondary)	-3.3%	[-4.3%, -2.2%]	3
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.1%, secondary -1.8%)

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)	-0.1%	[-0.1%, -0.0%]	5
Improvements ✅ (secondary)	-1.8%	[-6.2%, -0.2%]	12
All ❌✅ (primary)	-0.1%	[-0.1%, -0.0%]	5

Bootstrap: 473.373s -> 473.773s (0.08%)
Artifact size: 390.48 MiB -> 390.47 MiB (-0.00%)