Unschedule moved locals by cjgillot · Pull Request #159577 · rust-lang/rust

cjgillot · 2026-07-19T20:18:42Z

Alternative to #159537

This extracts part of the implementation from #125923.

Instead of maintaining a bit-set of locals that are moved from the innermost scope, this PR just removes the locals from the drop schedule.

r? @ghost for perf, and because of a borrowck corner case

And some more cases along the way. We have a specific optimization to avoid generating useless drops, use it. In particular, aggregate construction are very similar to function calls for which this is designed.

cjgillot · 2026-07-19T20:18:52Z

@bors try @rust-timer queue

Unschedule moved locals

rust-bors · 2026-07-19T22:13:05Z

☀️ Try build successful (CI)
Build commit: ab0430c (ab0430cfc09675383a04ad2a1b7877ec314aaac9)
Base parent: 9f36de7 (9f36de775bc636c8e88c31a173c2bcb6995956a0)

rust-timer · 2026-07-19T22:52:50Z

Finished benchmarking commit (ab0430c): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never 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)	0.5%	[0.4%, 0.5%]	6
Regressions ❌ (secondary)	0.3%	[0.2%, 0.3%]	2
Improvements ✅ (primary)	-0.5%	[-1.0%, -0.2%]	53
Improvements ✅ (secondary)	-0.4%	[-1.0%, -0.2%]	44
All ❌✅ (primary)	-0.4%	[-1.0%, 0.5%]	59

Max RSS (memory usage)

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

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)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.9%, -0.5%]	3
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	-0.7%	[-0.9%, -0.5%]	3

Cycles

Results (primary -2.3%, secondary -1.4%)

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)	-2.3%	[-2.4%, -2.3%]	2
Improvements ✅ (secondary)	-1.4%	[-1.4%, -1.4%]	1
All ❌✅ (primary)	-2.3%	[-2.4%, -2.3%]	2

Binary size

Results (primary -0.4%, secondary -0.2%)

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

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-1.9%, -0.0%]	42
Improvements ✅ (secondary)	-0.2%	[-1.9%, -0.0%]	30
All ❌✅ (primary)	-0.4%	[-1.9%, 0.6%]	43

Bootstrap: 484.26s -> 485.704s (0.30%)
Artifact size: 391.74 MiB -> 391.76 MiB (0.01%)

cjgillot · 2026-07-20T23:46:01Z

@bors try @rust-timer queue

Unschedule moved locals

rust-bors · 2026-07-21T01:42:14Z

☀️ Try build successful (CI)
Build commit: 563ed1f (563ed1fa91907743b81f0cbaac99dc8c8ad29077)
Base parent: 87e5904 (87e5904f5eb6398af6b22eac2802c78934260c48)

rust-timer · 2026-07-21T02:23:07Z

Finished benchmarking commit (563ed1f): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never 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)	1.3%	[0.2%, 11.7%]	65
Regressions ❌ (secondary)	0.7%	[0.1%, 2.0%]	66
Improvements ✅ (primary)	-0.3%	[-0.6%, -0.2%]	10
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	2
All ❌✅ (primary)	1.0%	[-0.6%, 11.7%]	75

Max RSS (memory usage)

Results (primary 1.7%, 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)	6.9%	[6.6%, 7.2%]	2
Regressions ❌ (secondary)	3.2%	[2.1%, 6.0%]	4
Improvements ✅ (primary)	-1.7%	[-3.5%, -0.8%]	3
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	1.7%	[-3.5%, 7.2%]	5

Cycles

Results (primary 10.9%, secondary -1.4%)

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

	mean	range	count
Regressions ❌ (primary)	10.9%	[1.9%, 23.2%]	6
Regressions ❌ (secondary)	5.9%	[5.9%, 5.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.8%	[-4.2%, -3.5%]	3
All ❌✅ (primary)	10.9%	[1.9%, 23.2%]	6

Binary size

Results (primary -0.4%, secondary -0.2%)

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

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-1.9%, -0.0%]	42
Improvements ✅ (secondary)	-0.2%	[-1.9%, -0.0%]	29
All ❌✅ (primary)	-0.4%	[-1.9%, 0.6%]	43

Bootstrap: 486.983s -> 486.82s (-0.03%)
Artifact size: 391.82 MiB -> 391.79 MiB (-0.01%)

cjgillot · 2026-07-22T00:42:06Z

@bors try @rust-timer queue

Unschedule moved locals

rust-log-analyzer · 2026-07-22T01:19:06Z

The job aarch64-gnu-llvm-21-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

test [mir-opt] tests/mir-opt/unusual_item_types.rs ... ok

failures:

---- [mir-opt] tests/mir-opt/nll/critical_unwind_edge.rs stdout ----
49 | '?19 live at {bb5[10]}
50 | '?20 live at {bb0[4]}
51 | '?21 live at {bb0[6]}
- | '?0: '?10 due to Predicate($DIR/critical_unwind_edge.rs:26:8: 26:27 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?0: '?10 due to Predicate($DIR/critical_unwind_edge.rs:26:14: 26:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?0: '?13 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:37:21: 37:40 (#0)
- | '?2: '?3 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?3: '?4 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?4: '?3 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?4: '?20 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?5: '?15 due to Boring at Single(bb0[4]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?6: '?14 due to Boring at Single(bb0[5]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?7: '?16 due to Assignment at Single(bb5[3]) ($DIR/critical_unwind_edge.rs:40:23: 40:31 (#0)
- | '?8: '?9 due to Predicate($DIR/critical_unwind_edge.rs:26:14: 26:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?8: '?11 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?9: '?8 due to Predicate($DIR/critical_unwind_edge.rs:26:14: 26:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?9: '?17 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?10: '?0 due to Predicate($DIR/critical_unwind_edge.rs:26:8: 26:27 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?10: '?0 due to Predicate($DIR/critical_unwind_edge.rs:26:14: 26:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?11: '?8 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?12: '?17 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:41:10: 41:19 (#0)
- | '?12: '?21 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:37:21: 37:40 (#0)
- | '?13: '?18 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:41:10: 41:19 (#0)
- | '?14: '?21 due to CallArgument(Some(FnDef(DefId(0:12 ~ critical_unwind_edge[72cc]::make_dyn_trait), Binder { value: [], bound_vars: [] }))) at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:37:21: 37:40 (#0)
- | '?15: '?6 due to Boring at Single(bb0[5]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?16: '?19 due to Boring at Single(bb5[9]) ($DIR/critical_unwind_edge.rs:41:21: 41:32 (#0)
- | '?17: '?9 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?17: '?12 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:41:10: 41:19 (#0)
- | '?18: '?10 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?19: '?11 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:41:5: 41:33 (#0)
- | '?20: '?5 due to Boring at Single(bb0[4]) ($DIR/critical_unwind_edge.rs:37:36: 37:39 (#0)
- | '?21: '?12 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:37:21: 37:40 (#0)
+ | '?0: '?10 due to Predicate($DIR/critical_unwind_edge.rs:27:8: 27:27 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?0: '?10 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?0: '?13 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:38:21: 38:40 (#0)
+ | '?2: '?3 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?3: '?4 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?4: '?3 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?4: '?20 due to Boring at Single(bb0[3]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?5: '?15 due to Boring at Single(bb0[4]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?6: '?14 due to Boring at Single(bb0[5]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?7: '?16 due to Assignment at Single(bb5[3]) ($DIR/critical_unwind_edge.rs:41:23: 41:31 (#0)
+ | '?8: '?9 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?8: '?11 due to Predicate($DIR/critical_unwind_edge.rs:28:14: 28:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?9: '?8 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?9: '?17 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?10: '?0 due to Predicate($DIR/critical_unwind_edge.rs:27:8: 27:27 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?10: '?0 due to Predicate($DIR/critical_unwind_edge.rs:27:14: 27:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?11: '?8 due to Predicate($DIR/critical_unwind_edge.rs:28:14: 28:26 (#0)) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?12: '?17 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:42:10: 42:19 (#0)
+ | '?12: '?21 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:38:21: 38:40 (#0)
+ | '?13: '?18 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:42:10: 42:19 (#0)
+ | '?14: '?21 due to CallArgument(Some(FnDef(DefId(0:12 ~ critical_unwind_edge[72cc]::make_dyn_trait), Binder { value: [], bound_vars: [] }))) at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:38:21: 38:40 (#0)
+ | '?15: '?6 due to Boring at Single(bb0[5]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?16: '?19 due to Boring at Single(bb5[9]) ($DIR/critical_unwind_edge.rs:42:21: 42:32 (#0)
+ | '?17: '?9 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?17: '?12 due to Boring at Single(bb5[7]) ($DIR/critical_unwind_edge.rs:42:10: 42:19 (#0)
+ | '?18: '?10 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?19: '?11 due to CallArgument(Some(FnDef(DefId(0:13 ~ critical_unwind_edge[72cc]::diff), Binder { value: ['{erased}, (), std::boxed::Box<dyn [Binder { value: Trait(Trait), bound_vars: [] }, Binder { value: Projection(ExistentialProjection { def_id: DefId(0:4 ~ critical_unwind_edge[72cc]::Trait::Item), args: [], term: Term::Ty(&'{erased} ()), .. }), bound_vars: [] }] + '{erased}, std::alloc::Global>, &'{erased} std::vec::Vec<(), std::alloc::Global>], bound_vars: [] }))) at Single(bb5[10]) ($DIR/critical_unwind_edge.rs:42:5: 42:33 (#0)
+ | '?20: '?5 due to Boring at Single(bb0[4]) ($DIR/critical_unwind_edge.rs:38:36: 38:39 (#0)
+ | '?21: '?12 due to Assignment at Single(bb0[6]) ($DIR/critical_unwind_edge.rs:38:21: 38:40 (#0)
81 |
82 | Borrows
83 | bw0: issued at bb5[3] in '?7


thread '[mir-opt] tests/mir-opt/nll/critical_unwind_edge.rs' panicked at src/tools/compiletest/src/runtest/mir_opt.rs:73:21:
Actual MIR output differs from expected MIR output /checkout/tests/mir-opt/nll/critical_unwind_edge.main.nll.0.64bit.mir
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
---- [mir-opt] tests/mir-opt/nll/critical_unwind_edge.rs stdout end ----

failures:
    [mir-opt] tests/mir-opt/nll/critical_unwind_edge.rs

rust-bors · 2026-07-22T02:46:57Z

☀️ Try build successful (CI)
Build commit: 5c95d39 (5c95d397a217a2ad69c501c978c9ec972fb53549)
Base parent: 0e29c21 (0e29c21d93abc9bdc330182be1fbd33cfd5fee68)

rust-timer · 2026-07-22T03:48:12Z

Finished benchmarking commit (5c95d39): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never 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)	0.9%	[0.1%, 6.6%]	48
Regressions ❌ (secondary)	0.7%	[0.1%, 1.8%]	36
Improvements ✅ (primary)	-0.4%	[-0.6%, -0.2%]	12
Improvements ✅ (secondary)	-0.3%	[-0.4%, -0.2%]	4
All ❌✅ (primary)	0.6%	[-0.6%, 6.6%]	60

Max RSS (memory usage)

Results (primary 1.7%, secondary 1.7%)

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

	mean	range	count
Regressions ❌ (primary)	2.8%	[0.4%, 4.7%]	6
Regressions ❌ (secondary)	3.2%	[1.4%, 6.6%]	9
Improvements ✅ (primary)	-1.6%	[-2.5%, -0.7%]	2
Improvements ✅ (secondary)	-2.9%	[-5.1%, -0.8%]	3
All ❌✅ (primary)	1.7%	[-2.5%, 4.7%]	8

Cycles

Results (primary 4.9%, 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)	4.9%	[1.2%, 9.9%]	7
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.9%	[1.2%, 9.9%]	7

Binary size

Results (primary -0.4%, secondary -0.2%)

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

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-1.9%, -0.0%]	42
Improvements ✅ (secondary)	-0.2%	[-1.9%, -0.0%]	29
All ❌✅ (primary)	-0.4%	[-1.9%, 0.6%]	43

Bootstrap: 495.463s -> 486.653s (-1.78%)
Artifact size: 387.85 MiB -> 387.83 MiB (-0.00%)

cjgillot added 3 commits July 18, 2026 20:50

Mark locals used to construct Aggregates as moved.

60dabb4

And some more cases along the way. We have a specific optimization to avoid generating useless drops, use it. In particular, aggregate construction are very similar to function calls for which this is designed.

Add test.

d11ceca

Use a GrowableBitSet for moved_locals.

e8296a0

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jul 19, 2026