optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones #102750

the8472 · 2022-10-06T19:25:08Z

use std::ptr::addr_of;
use std::mem;

struct Foo {
    word: u32,
    byte: u8,
    ary: [u8; 4]
}

fn main() {
    let foo: Foo = unsafe { mem::zeroed() };

    println!("base: {:p}\nword: {:p}\nbyte: {:p}\nary:  {:p}", &foo, addr_of!(foo.word), addr_of!(foo.byte), addr_of!(foo.ary));
}

prints

base: 0x7fffc1a8a668
word: 0x7fffc1a8a668
byte: 0x7fffc1a8a66c
ary:  0x7fffc1a8a66d

I.e. the u8 in the middle causes the array to sit at an odd offset, which might prevent optimizations, especially on architectures where unaligned loads are costly.

Note that this will make field ordering niche-dependent, i.e. a Bar<T> with T=char and T=u32 may result in different field order, this may break some code that makes invalid assumptions about repr(Rust) types.

rust-highfive · 2022-10-06T19:25:11Z

r? @wesleywiser

(rust-highfive has picked a reviewer for you, use r? to override)

the8472 · 2022-10-06T21:38:15Z

@bors try @rust-timer queue

rust-timer · 2022-10-06T21:38:17Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-10-06T21:38:23Z

⌛ Trying commit 2657f87590b84095f88c24ee525ec073963f9789 with merge baf56fd405dcb58b0e0470dd22880f87fb4dfe00...

bors · 2022-10-06T21:52:27Z

💔 Test failed - checks-actions

the8472 · 2022-10-06T23:11:55Z

@bors try

bors · 2022-10-06T23:12:05Z

⌛ Trying commit 36e29466a9342424ae2ffeea8a31c0a2f85c94c9 with merge 1db897b92c4dbe666c676afce1afc7278d6de594...

bors · 2022-10-07T01:02:23Z

☀️ Try build successful - checks-actions
Build commit: 1db897b92c4dbe666c676afce1afc7278d6de594 (1db897b92c4dbe666c676afce1afc7278d6de594)

rust-timer · 2022-10-07T01:02:26Z

Queued 1db897b92c4dbe666c676afce1afc7278d6de594 with parent 0ca3565, future comparison URL.

rust-timer · 2022-10-07T02:24:02Z

Finished benchmarking commit (1db897b92c4dbe666c676afce1afc7278d6de594): comparison URL.

Overall result: ❌✅ regressions and improvements - 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-review -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.

	mean¹	range	count²
Regressions ❌ (primary)	0.6%	[0.5%, 0.8%]	2
Regressions ❌ (secondary)	1.0%	[0.3%, 1.6%]	20
Improvements ✅ (primary)	-0.6%	[-2.1%, -0.2%]	69
Improvements ✅ (secondary)	-0.9%	[-2.8%, -0.2%]	44
All ❌✅ (primary)	-0.6%	[-2.1%, 0.8%]	71

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.

	mean¹	range	count²
Regressions ❌ (primary)	1.5%	[0.8%, 2.3%]	17
Regressions ❌ (secondary)	3.4%	[1.6%, 5.6%]	13
Improvements ✅ (primary)	-1.1%	[-1.4%, -0.7%]	3
Improvements ✅ (secondary)	-3.0%	[-4.3%, -2.2%]	4
All ❌✅ (primary)	1.1%	[-1.4%, 2.3%]	20

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.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.8%	[-1.8%, -1.8%]	1
Improvements ✅ (secondary)	-3.1%	[-5.1%, -1.8%]	12
All ❌✅ (primary)	-1.8%	[-1.8%, -1.8%]	1

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

compiler/rustc_ty_utils/src/layout.rs

the8472 · 2022-10-07T18:42:23Z

Perf results lean positive. Added tests.

@rustbot ready

nnethercote · 2022-11-24T21:59:43Z

The post-merge perf result was less clearly positive than the earlier one, though overall it looks roughly neutral, albeit with lots of changes in both directions.

@rustbot label: +perf-regression-triaged

joshtriplett · 2023-01-06T22:19:54Z

Marking this as relnotes, since people are noticing the layout changes in their structs. The relnotes should remind people that the layout of repr(Rust) isn't guaranteed, but we should still point to the change so that people know what happened.

Fixes an incorrect assumption that was broken in [Rust PR 102750](rust-lang/rust#102750)

Pkgsrc changes: * Adjust patches and cargo checksums to new versions, but also one strange "mips" conditional. Upstream changes: Version 1.67.0 (2023-01-26) ========================== Language -------- - [Make `Sized` predicates coinductive, allowing cycles.] (rust-lang/rust#100386) - [`#[must_use]` annotations on `async fn` also affect the `Future::Output`.] (rust-lang/rust#100633) - [Elaborate supertrait obligations when deducing closure signatures.] (rust-lang/rust#101834) - [Invalid literals are no longer an error under `cfg(FALSE)`.] (rust-lang/rust#102944) - [Unreserve braced enum variants in value namespace.] (rust-lang/rust#103578) Compiler -------- - [Enable varargs support for calling conventions other than `C` or `cdecl`.] (rust-lang/rust#97971) - [Add new MIR constant propagation based on dataflow analysis.] (rust-lang/rust#101168) - [Optimize field ordering by grouping m\*2^n-sized fields with equivalently aligned ones.] (rust-lang/rust#102750) - [Stabilize native library modifier `verbatim`.] (rust-lang/rust#104360) Added and removed targets: - [Add a tier 3 target for PowerPC on AIX] (rust-lang/rust#102293), `powerpc64-ibm-aix`. - [Add a tier 3 target for the Sony PlayStation 1] (rust-lang/rust#102689), `mipsel-sony-psx`. - [Add tier 3 `no_std` targets for the QNX Neutrino RTOS] (rust-lang/rust#102701), `aarch64-unknown-nto-qnx710` and `x86_64-pc-nto-qnx710`. - [Remove tier 3 `linuxkernel` targets] (rust-lang/rust#104015) (not used by the actual kernel). Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Merge `crossbeam-channel` into `std::sync::mpsc`.] (rust-lang/rust#93563) - [Fix inconsistent rounding of 0.5 when formatted to 0 decimal places.] (rust-lang/rust#102935) - [Derive `Eq` and `Hash` for `ControlFlow`.] (rust-lang/rust#103084) - [Don't build `compiler_builtins` with `-C panic=abort`.] (rust-lang/rust#103786) Stabilized APIs --------------- - [`{integer}::checked_ilog`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog) - [`{integer}::checked_ilog2`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog2) - [`{integer}::checked_ilog10`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog10) - [`{integer}::ilog`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog) - [`{integer}::ilog2`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog2) - [`{integer}::ilog10`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog10) - [`NonZeroU*::ilog2`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog2) - [`NonZeroU*::ilog10`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog10) - [`NonZero*::BITS`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#associatedconstant.BITS) These APIs are now stable in const contexts: - [`char::from_u32`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_u32) - [`char::from_digit`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_digit) - [`char::to_digit`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.to_digit) - [`core::char::from_u32`] (https://doc.rust-lang.org/stable/core/char/fn.from_u32.html) - [`core::char::from_digit`] (https://doc.rust-lang.org/stable/core/char/fn.from_digit.html) Compatibility Notes ------------------- - [The layout of `repr(Rust)` types now groups m\*2^n-sized fields with equivalently aligned ones.] (rust-lang/rust#102750) This is intended to be an optimization, but it is also known to increase type sizes in a few cases for the placement of enum tags. As a reminder, the layout of `repr(Rust)` types is an implementation detail, subject to change. - [0.5 now rounds to 0 when formatted to 0 decimal places.] (rust-lang/rust#102935) This makes it consistent with the rest of floating point formatting that rounds ties toward even digits. - [Chains of `&&` and `||` will now drop temporaries from their sub-expressions in evaluation order, left-to-right.] (rust-lang/rust#103293) Previously, it was "twisted" such that the _first_ expression dropped its temporaries _last_, after all of the other expressions dropped in order. - [Underscore suffixes on string literals are now a hard error.] (rust-lang/rust#103914) This has been a future-compatibility warning since 1.20.0. - [Stop passing `-export-dynamic` to `wasm-ld`.] (rust-lang/rust#105405) - [`main` is now mangled as `__main_void` on `wasm32-wasi`.] (rust-lang/rust#105468) - [Cargo now emits an error if there are multiple registries in the configuration with the same index URL.] (rust-lang/cargo#10592) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Rewrite LLVM's archive writer in Rust.] (rust-lang/rust#97485)

Pkgsrc changes: * Adjust patches (add & remove) and cargo checksums to new versions. * It's conceivable that the workaround for LLVM based NetBSD works even less in this version (ref. PKGSRC_HAVE_LIBCPP not having a corresponding patch anymore). Upstream changes: Version 1.68.2 (2023-03-28) =========================== - [Update the GitHub RSA host key bundled within Cargo] (rust-lang/cargo#11883). The key was [rotated by GitHub] (https://github.blog/2023-03-23-we-updated-our-rsa-ssh-host-key/) on 2023-03-24 after the old one leaked. - [Mark the old GitHub RSA host key as revoked] (rust-lang/cargo#11889). This will prevent Cargo from accepting the leaked key even when trusted by the system. - [Add support for `@revoked` and a better error message for `@cert-authority` in Cargo's SSH host key verification] (rust-lang/cargo#11635) Version 1.68.1 (2023-03-23) =========================== - [Fix miscompilation in produced Windows MSVC artifacts] (rust-lang/rust#109094) This was introduced by enabling ThinLTO for the distributed rustc which led to miscompilations in the resulting binary. Currently this is believed to be limited to the -Zdylib-lto flag used for rustc compilation, rather than a general bug in ThinLTO, so only rustc artifacts should be affected. - [Fix --enable-local-rust builds] (rust-lang/rust#109111) - [Treat `$prefix-clang` as `clang` in linker detection code] (rust-lang/rust#109156) - [Fix panic in compiler code] (rust-lang/rust#108162) Version 1.68.0 (2023-03-09) =========================== Language -------- - [Stabilize default_alloc_error_handler] (rust-lang/rust#102318) This allows usage of `alloc` on stable without requiring the definition of a handler for allocation failure. Defining custom handlers is still unstable. - [Stabilize `efiapi` calling convention.] (rust-lang/rust#105795) - [Remove implicit promotion for types with drop glue] (rust-lang/rust#105085) Compiler -------- - [Change `bindings_with_variant_name` to deny-by-default] (rust-lang/rust#104154) - [Allow .. to be parsed as let initializer] (rust-lang/rust#105701) - [Add `armv7-sony-vita-newlibeabihf` as a tier 3 target] (rust-lang/rust#105712) - [Always check alignment during compile-time const evaluation] (rust-lang/rust#104616) - [Disable "split dwarf inlining" by default.] (rust-lang/rust#106709) - [Add vendor to Fuchsia's target triple] (rust-lang/rust#106429) - [Enable sanitizers for s390x-linux] (rust-lang/rust#107127) Libraries --------- - [Loosen the bound on the Debug implementation of Weak.] (rust-lang/rust#90291) - [Make `std::task::Context` !Send and !Sync] (rust-lang/rust#95985) - [PhantomData layout guarantees] (rust-lang/rust#104081) - [Don't derive Debug for `OnceWith` & `RepeatWith`] (rust-lang/rust#104163) - [Implement DerefMut for PathBuf] (rust-lang/rust#105018) - [Add O(1) `Vec -> VecDeque` conversion guarantee] (rust-lang/rust#105128) - [Leak amplification for peek_mut() to ensure BinaryHeap's invariant is always met] (rust-lang/rust#105851) Stabilized APIs --------------- - [`{core,std}::pin::pin!`] (https://doc.rust-lang.org/stable/std/pin/macro.pin.html) - [`impl From<bool> for {f32,f64}`] (https://doc.rust-lang.org/stable/std/primitive.f32.html#impl-From%3Cbool%3E-for-f32) - [`std::path::MAIN_SEPARATOR_STR`] (https://doc.rust-lang.org/stable/std/path/constant.MAIN_SEPARATOR_STR.html) - [`impl DerefMut for PathBuf`] (https://doc.rust-lang.org/stable/std/path/struct.PathBuf.html#impl-DerefMut-for-PathBuf) These APIs are now stable in const contexts: - [`VecDeque::new`] (https://doc.rust-lang.org/stable/std/collections/struct.VecDeque.html#method.new) Cargo ----- - [Stabilize sparse registry support for crates.io] (rust-lang/cargo#11224) - [`cargo build --verbose` tells you more about why it recompiles.] (rust-lang/cargo#11407) - [Show progress of crates.io index update even `net.git-fetch-with-cli` option enabled] (rust-lang/cargo#11579) Misc ---- Compatibility Notes ------------------- - [Add `SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` to future-incompat report] (rust-lang/rust#103418) - [Only specify `--target` by default for `-Zgcc-ld=lld` on wasm] (rust-lang/rust#101792) - [Bump `IMPLIED_BOUNDS_ENTAILMENT` to Deny + ReportNow] (rust-lang/rust#106465) - [`std::task::Context` no longer implements Send and Sync] (rust-lang/rust#95985) nternal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Encode spans relative to the enclosing item] (rust-lang/rust#84762) - [Don't normalize in AstConv] (rust-lang/rust#101947) - [Find the right lower bound region in the scenario of partial order relations] (rust-lang/rust#104765) - [Fix impl block in const expr] (rust-lang/rust#104889) - [Check ADT fields for copy implementations considering regions] (rust-lang/rust#105102) - [rustdoc: simplify JS search routine by not messing with lev distance] (rust-lang/rust#105796) - [Enable ThinLTO for rustc on `x86_64-pc-windows-msvc`] (rust-lang/rust#103591) - [Enable ThinLTO for rustc on `x86_64-apple-darwin`] (rust-lang/rust#103647) Version 1.67.0 (2023-01-26) ========================== Language -------- - [Make `Sized` predicates coinductive, allowing cycles.] (rust-lang/rust#100386) - [`#[must_use]` annotations on `async fn` also affect the `Future::Output`.] (rust-lang/rust#100633) - [Elaborate supertrait obligations when deducing closure signatures.] (rust-lang/rust#101834) - [Invalid literals are no longer an error under `cfg(FALSE)`.] (rust-lang/rust#102944) - [Unreserve braced enum variants in value namespace.] (rust-lang/rust#103578) Compiler -------- - [Enable varargs support for calling conventions other than `C` or `cdecl`.] (rust-lang/rust#97971) - [Add new MIR constant propagation based on dataflow analysis.] (rust-lang/rust#101168) - [Optimize field ordering by grouping m\*2^n-sized fields with equivalently aligned ones.] (rust-lang/rust#102750) - [Stabilize native library modifier `verbatim`.] (rust-lang/rust#104360) Added and removed targets: - [Add a tier 3 target for PowerPC on AIX] (rust-lang/rust#102293), `powerpc64-ibm-aix`. - [Add a tier 3 target for the Sony PlayStation 1] (rust-lang/rust#102689), `mipsel-sony-psx`. - [Add tier 3 `no_std` targets for the QNX Neutrino RTOS] (rust-lang/rust#102701), `aarch64-unknown-nto-qnx710` and `x86_64-pc-nto-qnx710`. - [Remove tier 3 `linuxkernel` targets] (rust-lang/rust#104015) (not used by the actual kernel). Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. Libraries --------- - [Merge `crossbeam-channel` into `std::sync::mpsc`.] (rust-lang/rust#93563) - [Fix inconsistent rounding of 0.5 when formatted to 0 decimal places.] (rust-lang/rust#102935) - [Derive `Eq` and `Hash` for `ControlFlow`.] (rust-lang/rust#103084) - [Don't build `compiler_builtins` with `-C panic=abort`.] (rust-lang/rust#103786) Stabilized APIs --------------- - [`{integer}::checked_ilog`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog) - [`{integer}::checked_ilog2`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog2) - [`{integer}::checked_ilog10`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.checked_ilog10) - [`{integer}::ilog`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog) - [`{integer}::ilog2`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog2) - [`{integer}::ilog10`] (https://doc.rust-lang.org/stable/std/primitive.i32.html#method.ilog10) - [`NonZeroU*::ilog2`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog2) - [`NonZeroU*::ilog10`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#method.ilog10) - [`NonZero*::BITS`] (https://doc.rust-lang.org/stable/std/num/struct.NonZeroU32.html#associatedconstant.BITS) These APIs are now stable in const contexts: - [`char::from_u32`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_u32) - [`char::from_digit`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.from_digit) - [`char::to_digit`] (https://doc.rust-lang.org/stable/std/primitive.char.html#method.to_digit) - [`core::char::from_u32`] (https://doc.rust-lang.org/stable/core/char/fn.from_u32.html) - [`core::char::from_digit`] (https://doc.rust-lang.org/stable/core/char/fn.from_digit.html) Compatibility Notes ------------------- - [The layout of `repr(Rust)` types now groups m\*2^n-sized fields with equivalently aligned ones.] (rust-lang/rust#102750) This is intended to be an optimization, but it is also known to increase type sizes in a few cases for the placement of enum tags. As a reminder, the layout of `repr(Rust)` types is an implementation detail, subject to change. - [0.5 now rounds to 0 when formatted to 0 decimal places.] (rust-lang/rust#102935) This makes it consistent with the rest of floating point formatting that rounds ties toward even digits. - [Chains of `&&` and `||` will now drop temporaries from their sub-expressions in evaluation order, left-to-right.] (rust-lang/rust#103293) Previously, it was "twisted" such that the _first_ expression dropped its temporaries _last_, after all of the other expressions dropped in order. - [Underscore suffixes on string literals are now a hard error.] (rust-lang/rust#103914) This has been a future-compatibility warning since 1.20.0. - [Stop passing `-export-dynamic` to `wasm-ld`.] (rust-lang/rust#105405) - [`main` is now mangled as `__main_void` on `wasm32-wasi`.] (rust-lang/rust#105468) - [Cargo now emits an error if there are multiple registries in the configuration with the same index URL.] (rust-lang/cargo#10592) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Rewrite LLVM's archive writer in Rust.] (rust-lang/rust#97485)

After rust-lang/rust#102750 , Rust reorders fields in repr(Rust) structures based on size/alignment. Applying such reordering to the Dsp struct substantially hurts performance. Set repr(C) on the Dsp struct to recover that performance. See https://internals.rust-lang.org/t/unexpected-3-x-performance-regression-starting-with-rust-version-1-67/18724 for the test case and investigations that led to this.

Newer toolchains cause stack overflow errors in some tests. That may be related to a memory alignment change in Rust v1.67 (rust-lang/rust#102750)

After rust-lang/rust#102750 , Rust reorders fields in repr(Rust) structures based on size/alignment. Applying such reordering to the Dsp struct substantially hurts performance. Set repr(C) on the Dsp struct to recover that performance. See https://internals.rust-lang.org/t/unexpected-3-x-performance-regression-starting-with-rust-version-1-67/18724 for the test case and investigations that led to this.

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Oct 6, 2022

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the8472 force-pushed the opt-field-order branch from a8647dd to 1d58865 Compare October 6, 2022 19:45

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rustbot added perf-regression Performance regression. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Oct 7, 2022

the8472 force-pushed the opt-field-order branch from 36e2946 to bd4f801 Compare October 7, 2022 17:24

the8472 marked this pull request as ready for review October 7, 2022 18:08

erikdesjardins reviewed Oct 7, 2022

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compiler/rustc_ty_utils/src/layout.rs Show resolved Hide resolved

rustbot added the perf-regression-triaged The performance regression has been triaged. label Nov 24, 2022

teor2345 mentioned this pull request Dec 1, 2022

Improve VerifyBlockError::Commit typing, so we don't accidentally break syncer error handling ZcashFoundation/zebra#2908

Open

emilio mentioned this pull request Dec 6, 2022

#102750 regresses layout size of Cow<> #105371

Closed

tedinski mentioned this pull request Dec 29, 2022

Spurious failure with rust toolchain-2022-12-11 model-checking/kani#2051

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joshtriplett added the relnotes Marks issues that should be documented in the release notes of the next release. label Jan 6, 2023

adamgreig mentioned this pull request Jan 14, 2023

Embedded projects using synopsys-usb-otg are hanging in Beta/Nightly #106830

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antonok-edm mentioned this pull request Jan 14, 2023

Forever waiting for AHB clock in nightly stm32-rs/synopsys-usb-otg#33

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nbvdkamp mentioned this pull request Jan 16, 2023

Fields of Vertex struct being reordered on new rust version results in incorrect render hadronized/luminance-rs#616

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brooksprumo mentioned this pull request Jan 24, 2023

Audit types used by VM due to rust 1.68 memory layout changes solana-labs/solana#29852

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datdenkikniet pushed a commit to stm32-rs/stm32-eth that referenced this pull request Jan 24, 2023

Make all register blocks (with delays) Repr(C)

f4a4e7d

Fixes an incorrect assumption that was broken in [Rust PR 102750](rust-lang/rust#102750)

datdenkikniet mentioned this pull request Jan 24, 2023

Make all register blocks (with delays) Repr(C) stm32-rs/stm32-eth#65

Merged

datdenkikniet pushed a commit to datdenkikniet/stm32-eth that referenced this pull request Jan 24, 2023

Make all register blocks (with delays) Repr(C)

a68b891

Fixes an incorrect assumption that was broken in [Rust PR 102750](rust-lang/rust#102750)

alexheretic mentioned this pull request Jan 26, 2023

[v0.18] Use #[repr(C)] for vertex & constant structs. gfx-rs/gfx#3791

Merged

chamons mentioned this pull request Jan 30, 2023

ggez/rustc nightly regression ggez/ggez#1148

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tobz mentioned this pull request Jan 31, 2023

chore(deps): Update Rust to 1.67.1 vectordotdev/vector#16212

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jahofmann mentioned this pull request Feb 2, 2023

Struct packet_mreq requires repr(C) in rustc versions >= 1.67 libpnet/libpnet#600

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the8472 mentioned this pull request Mar 6, 2023

thread 'rustc' panicked at 'expected expression', compiler/rustc_expand/src/base.rs:176:18 #108426

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joshtriplett mentioned this pull request Apr 23, 2023

Set repr(C) on the Dsp struct to recover performance grame-cncm/faust#889

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pstuecker mentioned this pull request Sep 11, 2023

Fix incorrect memory layout on Rust >= 1.67.0 eclipse-set/browser#28

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stefanlippuner added a commit to stefanlippuner/moore that referenced this pull request Sep 30, 2023

Pin Rust toolchain version to v1.66

4db1509

Newer toolchains cause stack overflow errors in some tests. That may be related to a memory alignment change in Rust v1.67 (rust-lang/rust#102750)

stefanlippuner added a commit to stefanlippuner/moore that referenced this pull request Sep 30, 2023

Pin Rust toolchain version to v1.66

a825813

Newer toolchains cause stack overflow errors in some tests. That may be related to a memory alignment change in Rust v1.67 (rust-lang/rust#102750)

the8472 mentioned this pull request May 27, 2024

Missed enum layout optimization depending on enum variant field reordering #125630

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the8472 mentioned this pull request Jun 13, 2024

don't inhibit random field reordering on repr(packed(1)) #125360

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optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones #102750

optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones #102750

the8472 commented Oct 6, 2022 •

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optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones #102750

optimize field ordering by grouping m*2^n-sized fields with equivalently aligned ones #102750

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the8472 commented Oct 6, 2022 • edited Loading

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Overall result: ❌✅ regressions and improvements - ACTION NEEDED

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the8472 commented Oct 7, 2022

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the8472 commented Oct 6, 2022 •

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