interpret: avoid a long-lived PlaceTy in stack frames

[RalfJung]

PlaceTy uses a representation that's not very stable under changes to the stack. I'd feel better if we didn't have one in the long-term machine state.

r? @oli-obk

[rustbot]

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[RalfJung]

Let's see if this has a perf impact.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 8de72e4 with merge 1a272fb...

[RalfJung]

This now shows up as "pending" in the queue, even though it never got approved... for avoidance of doubt:
@bors r- force

[compiler-errors]

Let's try closing and reopening

[compiler-errors]

Or uh... a retry? That usually kicks a merge job.

@bors retry

[compiler-errors]

Cool it's gone

[RalfJung]

Okay let's get our try build going again then.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 8de72e4 with merge 96f5a38...

[bors]

☀️ Try build successful - checks-actions
Build commit: 96f5a38 (96f5a38dad266d234e141c769334d11beb29b4db)

[bors]

☀️ Try build successful - checks-actions
Build commit: 96f5a38 (96f5a38dad266d234e141c769334d11beb29b4db)

[RalfJung]

Ah that's why this felt so familiar... I made a similar experiment last year already: #113964. Damn.

I think I still don't understand why these return places are so hot though...

[rust-timer]

Finished benchmarking commit (96f5a38): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.3%, 0.3%]	1
Regressions ❌ (secondary)	2.8%	[0.2%, 4.9%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.3%, 0.3%]	1

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	2.5%	[2.5%, 2.5%]	1
Regressions ❌ (secondary)	2.7%	[2.1%, 3.4%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.2%	[-5.5%, -2.0%]	38
All ❌✅ (primary)	2.5%	[2.5%, 2.5%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.1%	[3.7%, 4.5%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 645.218s -> 642.92s (-0.36%)
Artifact size: 175.01 MiB -> 174.94 MiB (-0.04%)

[RalfJung]

That's a lot better than the last one. Only primary regression is in a doc build, I assume that's spurious. (If it was systematic it should affect the other builds as well.)

Might be acceptable for improved interpreter maintainability?

[rustbot]

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

[RalfJung]

Pushing this change in return place type through the rest of the interpreter, I found some things in Miri that definitely should not use PlaceTy... they are actually involved in concurrency.

OTOH this also changes the return place to MPlaceTy for intrinsics, which may or may not be a good idea.

@bors try @rust-timer queue

[bors]

⌛ Trying commit 3f0b6a0 with merge ee3afb2...

[bors]

☀️ Try build successful - checks-actions
Build commit: ee3afb2 (ee3afb22d066f6ffd3150dc097bced9d72b85de7)

[rust-timer]

Finished benchmarking commit (ee3afb2): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

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.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.3%, 0.3%]	1
Regressions ❌ (secondary)	3.2%	[0.2%, 4.4%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.3%, 0.3%]	1

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.8%	[1.9%, 7.2%]	15
Regressions ❌ (secondary)	3.1%	[0.5%, 7.5%]	78
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.8%	[1.9%, 7.2%]	15

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.3%	[4.0%, 4.6%]	6
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 643.087s -> 642.263s (-0.13%)
Artifact size: 174.99 MiB -> 174.96 MiB (-0.02%)

[RalfJung]

Seems like doing this also for intrinsics doesn't cost anything extra. :) That way we can keep the foreign-item and intrinsic paths consistent.

[oli-obk]

@bors r+

[bors]

📌 Commit 3f0b6a0 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 3f0b6a0 with merge 52f8aec...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 52f8aec to master...

[rust-timer]

Finished benchmarking commit (52f8aec): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Next Steps: If you can justify the regressions found in this perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please open an issue or create a new PR that fixes the regressions, add a comment linking to the newly created issue or PR, and then add the perf-regression-triaged label to this PR.

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.3%, 0.3%]	1
Regressions ❌ (secondary)	3.0%	[0.2%, 4.5%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.3%, 0.3%]	1

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	4.0%	[3.7%, 4.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.9%	[3.2%, 4.3%]	7
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 648.501s -> 647.761s (-0.11%)
Artifact size: 172.69 MiB -> 172.64 MiB (-0.03%)

[pnkfelix]

• primary regression was to html5ever doc-full; was anctipated during development and is presumed spurious.
• marking as triaged.

@rustbot label: +perf-regression-triaged