Stop backends from needing to support nullary intrinsics #142839

oli-obk · 2025-06-21T18:02:36Z

And then remove our infrastructure special casing them. Further improvements can now be done to them by avoiding the intermediate ConstValue step, but let's leave that to follow up work

r? @RalfJung

rustbot · 2025-06-21T18:02:41Z

Some changes occurred to the intrinsics. Make sure the CTFE / Miri interpreter
gets adapted for the changes, if necessary.

cc @rust-lang/miri, @RalfJung, @oli-obk, @lcnr

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

oli-obk · 2025-06-21T18:02:47Z

@bors try @rust-timer queue

bors · 2025-06-21T18:03:58Z

⌛ Trying commit a44843e with merge a5e9784...

Stop backends from needing to support nullary intrinsics And then remove our infrastructure special casing them. Further improvements can now be done to them by avoiding the intermediate ConstValue step, but let's leave that to follow up work r? `@ghost` wanna see perf first

fbstj · 2025-06-21T18:23:02Z

compiler/rustc_const_eval/src/interpret/intrinsics.rs


        match intrinsic_name {
+            sym::type_name => {


nit: I see this is a code-move & fixup to work in here, but is it worth sorting these arms into the rest of the match? though I guess the other arms are also not sorted simply... it was mostly that needs_drop is between type_id & type_name that caught my eye hehe

yea, could do that, good point. didn't want to do it in the first commit to kinda make the diff line up

bors · 2025-06-21T20:32:32Z

☀️ Try build successful - checks-actions
Build commit: a5e9784 (a5e97845d0268f3cbfc1f7da350c0e9127ab0b99)

rust-timer · 2025-06-22T00:55:19Z

Finished benchmarking commit (a5e9784): 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)	3.2%	[2.8%, 3.5%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.3%, -0.3%]	1
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.2%]	2
All ❌✅ (primary)	2.0%	[-0.3%, 3.5%]	3

Max RSS (memory usage)

Results (primary 3.7%)

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

	mean	range	count
Regressions ❌ (primary)	3.7%	[2.0%, 5.5%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.7%	[2.0%, 5.5%]	2

Cycles

Results (primary 2.7%, secondary -6.5%)

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

	mean	range	count
Regressions ❌ (primary)	2.7%	[2.7%, 2.8%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-6.5%	[-6.5%, -6.5%]	1
All ❌✅ (primary)	2.7%	[2.7%, 2.8%]	2

Binary size

Results (primary 0.4%)

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

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.0%, 1.1%]	9
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.1%, -0.0%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-0.1%, 1.1%]	11

Bootstrap: 691.091s -> 687.91s (-0.46%)
Artifact size: 371.86 MiB -> 371.89 MiB (0.01%)

rustbot · 2025-06-24T08:52:38Z

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo, @GuillaumeGomez

compiler/rustc_codegen_gcc/example/mini_core_hello_world.rs

rustbot · 2025-06-27T08:44:57Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

rustbot · 2025-06-27T10:30:59Z

The Miri subtree was changed

cc @rust-lang/miri

oli-obk · 2025-06-27T12:14:43Z

@rustbot ready

RalfJung · 2025-06-27T12:41:43Z

The core parts LGTM, but I have no idea how to review the stable MIR test changes.
Cc @celinval

bors · 2025-06-27T20:20:22Z

☔ The latest upstream changes (presumably #143091) made this pull request unmergeable. Please resolve the merge conflicts.

celinval · 2025-06-28T06:31:06Z

The core parts LGTM, but I have no idea how to review the stable MIR test changes. Cc @celinval

The test changes make sense to me. Thanks for checking!

RalfJung · 2025-06-28T07:24:03Z

Thanks! r=RalfJung,celinval after a rebase.

…er intrinsics

…itly deciding not to

oli-obk · 2025-06-30T08:05:37Z

@bors r=RalfJung,celinval rollup

bors · 2025-06-30T08:05:41Z

📌 Commit d0bb9a7 has been approved by RalfJung,celinval

It is now in the queue for this repository.

oli-obk · 2025-06-30T08:05:51Z

@bors rollup=never

bors · 2025-06-30T11:24:50Z

⌛ Testing commit d0bb9a7 with merge ad3b725...

bors · 2025-06-30T14:27:51Z

☀️ Test successful - checks-actions
Approved by: RalfJung,celinval
Pushing ad3b725 to master...

github-actions · 2025-06-30T14:30:51Z

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 f191420 (parent) -> ad3b725 (this PR)

Test differences

No test diffs found

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard ad3b7257615c28aaf8212a189ec032b8af75de51 --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

x86_64-apple-2: 3935.1s -> 5810.6s (47.7%)
dist-apple-various: 5248.9s -> 6258.5s (19.2%)
dist-ohos-aarch64: 4134.0s -> 4807.9s (16.3%)
x86_64-rust-for-linux: 2968.4s -> 2636.5s (-11.2%)
mingw-check-1: 1779.3s -> 1586.0s (-10.9%)
dist-powerpc64le-linux-gnu: 5107.8s -> 5638.7s (10.4%)
x86_64-gnu-llvm-20-1: 3713.1s -> 3328.6s (-10.4%)
i686-gnu-1: 8126.1s -> 7307.7s (-10.1%)
x86_64-apple-1: 6599.9s -> 7243.8s (9.8%)
dist-loongarch64-linux: 5932.1s -> 6413.6s (8.1%)

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 · 2025-06-30T15:54:29Z

Finished benchmarking commit (ad3b725): comparison URL.

Overall result: ❌✅ regressions and improvements - BENCHMARK(S) FAILED

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

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

❗ ❗ ❗ ❗ ❗
Warning ⚠️: The following benchmark(s) failed to build:

include-blob

❗ ❗ ❗ ❗ ❗

cc @rust-lang/wg-compiler-performance

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)	2.7%	[2.7%, 2.7%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.4%, -0.3%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-0.4%, 2.7%]	6

Max RSS (memory usage)

Results (primary -0.9%, 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)	5.1%	[5.0%, 5.1%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.8%	[-7.8%, -1.1%]	3
Improvements ✅ (secondary)	-1.7%	[-1.7%, -1.7%]	1
All ❌✅ (primary)	-0.9%	[-7.8%, 5.1%]	5

Cycles

Results (primary 2.4%)

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

	mean	range	count
Regressions ❌ (primary)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.4%	[2.4%, 2.4%]	1

Binary size

Results (primary 0.2%)

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

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.0%, 1.1%]	8
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.0%	[-0.1%, -0.0%]	5
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[-0.1%, 1.1%]	13

Bootstrap: 695.172s -> 694.099s (-0.15%)
Artifact size: 372.16 MiB -> 372.14 MiB (-0.00%)

Kobzol · 2025-06-30T16:08:07Z

You can ignore the failure, it's a (temporary) bug in the benchmark suite.

EDIT: fixed now

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jun 21, 2025