Skip to content

Remove Rvalue::Len again. #146564

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Merged
merged 3 commits into from
Sep 17, 2025
Merged

Remove Rvalue::Len again. #146564

merged 3 commits into from
Sep 17, 2025

Conversation

cjgillot
Copy link
Contributor

Now that we have RawPtrKind::FakeForPtrMetadata, we can reimplement Rvalue::Len using PtrMetadata(&raw const (fake) place).

r? @scottmcm

@rustbot
Copy link
Collaborator

rustbot commented Sep 14, 2025

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 in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

Some changes occurred in compiler/rustc_codegen_ssa

cc @WaffleLapkin

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

This PR changes MIR

cc @oli-obk, @RalfJung, @JakobDegen, @vakaras

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred to constck

cc @fee1-dead

Some changes occurred in match lowering

cc @Nadrieril

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

This PR changes rustc_public

cc @oli-obk, @celinval, @ouz-a

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-clippy Relevant to the Clippy team. 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 Sep 14, 2025
@cjgillot cjgillot force-pushed the mir-nolen branch 3 times, most recently from 3114e1b to 7613fdb Compare September 14, 2025 23:57
@rust-log-analyzer

This comment has been minimized.

Sign in to view
scottmcm
scottmcm approved these changes Sep 16, 2025
View reviewed changes
Copy link
Member

@scottmcm scottmcm left a comment •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thanks for picking this up!

Put a couple of thoughts for you to think about, but r=me even without them if you think they're not needed.

View changes since this review

tests/mir-opt/instsimplify/combine_array_len.rs Outdated
// EMIT_MIR combine_array_len.norm2.InstSimplify-after-simplifycfg.diff
fn norm2(x: [f32; 2]) -> f32 {
// CHECK-LABEL: fn norm2(
// CHECK-NOT: Len(
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think this also needs CHECK-NOT: PtrMetadata or something? Since of course there's no Len now.

compiler/rustc_mir_build/src/builder/matches/test.rs
// actual = len(place)
self.cfg.push_assign(block, source_info, actual, Rvalue::Len(place));
let length_op = self.len_of_slice_or_array(block, place, test.span, source_info);
self.cfg.push_assign(block, source_info, actual, Rvalue::Use(length_op));
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Now that this can be _3 = 4_usize; instead of _3 = Len(_2);, should we have a MIR building test that shows that?

@rustbot
Copy link
Collaborator

rustbot commented Sep 16, 2025

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.

@scottmcm
Copy link
Member

Thanks! Looks great.

@bors r+ rollup=iffy

@bors
Copy link
Collaborator

bors commented Sep 17, 2025

📌 Commit de73af9 has been approved by scottmcm

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 17, 2025
Zalathar added a commit to Zalathar/rust that referenced this pull request Sep 17, 2025
@Zalathar
Rollup merge of rust-lang#146564 - cjgillot:mir-nolen, r=scottmcm
b67e165 
Remove Rvalue::Len again.

Now that we have `RawPtrKind::FakeForPtrMetadata`, we can reimplement `Rvalue::Len` using `PtrMetadata(&raw const (fake) place)`.

r? `@scottmcm`
This was referenced Sep 17, 2025
Closed
Merged
Merged
bors added a commit that referenced this pull request Sep 17, 2025
@bors
Auto merge of #146666 - Zalathar:rollup-m2b8low, r=Zalathar
2ebb126 
Rollup of 14 pull requests

Successful merges:

 - #142807 (libtest: expose --fail-fast as an unstable command-line option)
 - #144871 (Stabilize `btree_entry_insert` feature)
 - #145071 (Update the minimum external LLVM to 20)
 - #145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables)
 - #145660 (initial implementation of the darwin_objc unstable feature)
 - #145838 (don't apply temporary lifetime extension rules to non-extended `super let`)
 - #146259 (Suggest removing Box::new instead of unboxing it)
 - #146410 (Iterator repeat: no infinite loop for `last` and `count`)
 - #146460 (Add tidy readme)
 - #146552 (StateTransform: Do not renumber resume local.)
 - #146564 (Remove Rvalue::Len again.)
 - #146581 (Detect attempt to use var-args in closure)
 - #146588 (tests/run-make: Update list of statically linked musl targets)
 - #146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3))

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 6473a0f into rust-lang:master Sep 17, 2025
10 checks passed
@rustbot rustbot added this to the 1.92.0 milestone Sep 17, 2025
rust-timer added a commit that referenced this pull request Sep 17, 2025
@rust-timer
Unrolled build for #146564
cd9fb54 
Rollup merge of #146564 - cjgillot:mir-nolen, r=scottmcm

Remove Rvalue::Len again.

Now that we have `RawPtrKind::FakeForPtrMetadata`, we can reimplement `Rvalue::Len` using `PtrMetadata(&raw const (fake) place)`.

r? ``@scottmcm``
@cjgillot cjgillot deleted the mir-nolen branch September 17, 2025 10:50
@IntegralPilot IntegralPilot mentioned this pull request Sep 18, 2025
Merged
tautschnig added a commit to tautschnig/kani that referenced this pull request Sep 18, 2025
@tautschnig
Upgrade Rust toolchain to 2025-09-18
00415f9 
Relevant upstream PR:
- rust-lang/rust#146564 (Remove Rvalue::Len again.)

Resolves: model-checking#4365
@tautschnig tautschnig mentioned this pull request Sep 18, 2025
Merged
@github-actions github-actions bot mentioned this pull request Sep 18, 2025
Draft
github-merge-queue bot pushed a commit to model-checking/kani that referenced this pull request Sep 18, 2025
@tautschnig
Upgrade Rust toolchain to 2025-09-18 (#4366)
bfb22f1 
Relevant upstream PR:
- rust-lang/rust#146564 (Remove Rvalue::Len
again.)

Resolves: #4365

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.
github-actions bot pushed a commit to rust-lang/rustc-dev-guide that referenced this pull request Sep 22, 2025
@bors
Auto merge of #146666 - Zalathar:rollup-m2b8low, r=Zalathar
f81ad3e 
Rollup of 14 pull requests

Successful merges:

 - rust-lang/rust#142807 (libtest: expose --fail-fast as an unstable command-line option)
 - rust-lang/rust#144871 (Stabilize `btree_entry_insert` feature)
 - rust-lang/rust#145071 (Update the minimum external LLVM to 20)
 - rust-lang/rust#145181 (remove FIXME block from `has_significant_drop`, it never encounters inference variables)
 - rust-lang/rust#145660 (initial implementation of the darwin_objc unstable feature)
 - rust-lang/rust#145838 (don't apply temporary lifetime extension rules to non-extended `super let`)
 - rust-lang/rust#146259 (Suggest removing Box::new instead of unboxing it)
 - rust-lang/rust#146410 (Iterator repeat: no infinite loop for `last` and `count`)
 - rust-lang/rust#146460 (Add tidy readme)
 - rust-lang/rust#146552 (StateTransform: Do not renumber resume local.)
 - rust-lang/rust#146564 (Remove Rvalue::Len again.)
 - rust-lang/rust#146581 (Detect attempt to use var-args in closure)
 - rust-lang/rust#146588 (tests/run-make: Update list of statically linked musl targets)
 - rust-lang/rust#146631 (cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3))

r? `@ghost`
`@rustbot` modify labels: rollup
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@scottmcm scottmcm scottmcm approved these changes

Assignees

@scottmcm scottmcm

Labels
S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-clippy Relevant to the Clippy team. 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.
Projects
None yet
Milestone
1.92.0
Development

Successfully merging this pull request may close these issues.
5 participants
@cjgillot @rustbot @rust-log-analyzer @scottmcm @bors