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Add select_unpredictable to force LLVM to use CMOV #128250

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merged 1 commit into from
Jul 30, 2024

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@Amanieu Amanieu commented Jul 26, 2024

Since https://reviews.llvm.org/D118118, LLVM will no longer turn CMOVs into branches if it comes from a select marked with an unpredictable metadata attribute.

This PR introduces core::intrinsics::select_unpredictable which emits such a select and uses it in the implementation of binary_search_by.

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rustbot commented Jul 26, 2024

r? @joboet

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@rustbot 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 Jul 26, 2024
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Amanieu commented Jul 26, 2024

r? compiler

@rustbot rustbot assigned petrochenkov and unassigned joboet Jul 26, 2024
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klensy commented Jul 26, 2024

Can title mention new intrinsic? This way it's easier to find new things.

@Amanieu Amanieu changed the title Force LLVM to use CMOV for binary search Add select_unpredictable to force LLVM to use CMOV for binary search Jul 26, 2024
@Amanieu Amanieu changed the title Add select_unpredictable to force LLVM to use CMOV for binary search Add select_unpredictable to force LLVM to use CMOV Jul 26, 2024
Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 26, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 26, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 27, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 27, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 27, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
args[1].layout.llvm_type(self)
};
let ptr = select(self, true_val.llval, false_val.llval);
let out = self.load(llty, ptr, true_val.align);
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We should not perform aggregate loads. I think what you want to do here is something like OperandValue::Ref(ptr).store(self, result), which lowers to a memcpy.

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I've updated it to do that. I'm still not entirely sure if it's doing the right thing, but at least it does the same thing as black_box now.

Since https://reviews.llvm.org/D118118, LLVM will no longer turn CMOVs
into branches if it comes from a `select` marked with an `unpredictable`
metadata attribute.

This PR introduces `core::intrinsics::select_unpredictable` which emits
such a `select` and uses it in the implementation of `binary_search_by`.
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r? @nikic

@rustbot rustbot assigned nikic and unassigned petrochenkov Jul 29, 2024
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nikic commented Jul 29, 2024

@bors r+ rollup=never

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bors commented Jul 29, 2024

📌 Commit 4f78f9f has been approved by nikic

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 Jul 29, 2024
#[no_mangle]
pub fn test_zst(p: bool, a: (), b: ()) -> () {
// CHECK-LABEL: define{{.*}} @test_zst
core::intrinsics::select_unpredictable(p, a, b)
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Maybe?

Suggested change
core::intrinsics::select_unpredictable(p, a, b)
core::intrinsics::select_unpredictable(p, a, b)
// CHECK-NOT: select i1
// CHECK: ret void

Otherwise, I don't know what we are supposed to be testing.

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bors commented Jul 30, 2024

⌛ Testing commit 4f78f9f with merge 710ce90...

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bors commented Jul 30, 2024

☀️ Test successful - checks-actions
Approved by: nikic
Pushing 710ce90 to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Jul 30, 2024
@bors bors merged commit 710ce90 into rust-lang:master Jul 30, 2024
7 checks passed
@rustbot rustbot added this to the 1.82.0 milestone Jul 30, 2024
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Finished benchmarking commit (710ce90): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -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
Regressions ❌
(secondary)
0.3% [0.2%, 0.5%] 5
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) - - 0

Max RSS (memory usage)

Results (primary 0.6%)

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)
0.6% [0.6%, 0.6%] 1
Regressions ❌
(secondary)
- - 0
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) 0.6% [0.6%, 0.6%] 1

Cycles

Results (secondary 2.7%)

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)
2.7% [2.2%, 3.1%] 5
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) - - 0

Binary size

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

Bootstrap: 770.597s -> 771.833s (0.16%)
Artifact size: 331.91 MiB -> 331.86 MiB (-0.02%)

Amanieu added a commit to Amanieu/rust that referenced this pull request Jul 30, 2024
This restores the original binary search implementation from rust-lang#45333
which has the nice property of having a loop count that only depends on
the size of the slice. This, along with explicit conditional moves
from rust-lang#128250, means that the entire binary search loop can be perfectly
predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is
known at compile-time. This results in a very compact code sequence of
3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
bors added a commit to rust-lang-ci/rust that referenced this pull request Jul 30, 2024
Rewrite binary search implementation

This PR builds on top of rust-lang#128250, which should be merged first.

This restores the original binary search implementation from rust-lang#45333 which has the nice property of having a loop count that only depends on the size of the slice. This, along with explicit conditional moves from rust-lang#128250, means that the entire binary search loop can be perfectly predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is known at compile-time. This results in a very compact code sequence of 3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Fixes rust-lang#115271
bors added a commit to rust-lang-ci/rust that referenced this pull request Aug 2, 2024
Rewrite binary search implementation

This PR builds on top of rust-lang#128250, which should be merged first.

This restores the original binary search implementation from rust-lang#45333 which has the nice property of having a loop count that only depends on the size of the slice. This, along with explicit conditional moves from rust-lang#128250, means that the entire binary search loop can be perfectly predicted by the branch predictor.

Additionally, LLVM is able to unroll the loop when the slice length is known at compile-time. This results in a very compact code sequence of 3-4 instructions per binary search step and zero branches.

Fixes rust-lang#53823
Fixes rust-lang#115271
carolynzech added a commit to model-checking/verify-rust-std that referenced this pull request Aug 15, 2024
9cc3bc6add3 custom MIR: add support for tail calls
5674d1c07e5 Auto merge of rust-lang#128673 - matthiaskrgr:rollup-gtvpkm7, r=matthiaskrgr
deb1d7576df Rollup merge of rust-lang#128619 - glandium:last_chunk, r=scottmcm
6449537a625 Rollup merge of rust-lang#128609 - swenson:smaller-faster-dragon, r=Amanieu
acb2c303c36 Rollup merge of rust-lang#128026 - devnexen:available_parallelism_vxworks, r=Mark-Simulacrum
89fe6dfa6b9 Rollup merge of rust-lang#128309 - kmicklas:btreeset-cursor, r=Amanieu
313484bb62c Correct the const stabilization of `<[T]>::last_chunk`
22e026b048c Auto merge of rust-lang#128534 - bjorn3:split_stdlib_workspace, r=Mark-Simulacrum
18136032131 Rollup merge of rust-lang#128526 - tshepang:patch-1, r=Amanieu
e8a1a4151ee Auto merge of rust-lang#128466 - sayantn:stdarch-update, r=tgross35
2adf9da42a3 Update stdarch
dc85bdb60ce Chore: add `x86_amx_intrinsics` feature flag to `core/lib.rs` and remove `issue-120720-reduce-nan.rs`
e88b04d135d Rollup merge of rust-lang#128551 - Konippi:refactor-backtrace-style-in-panic, r=tgross35
43a1e939ebe Rollup merge of rust-lang#128530 - scottmcm:repeat-n-unchecked, r=joboet
47df194eec6 Remove unnecessary constants from flt2dec dragon
0b5f1b8406f Auto merge of rust-lang#128404 - compiler-errors:revert-dead-code-changes, r=pnkfelix
35cd95f1edb Suppress new false-negatives that were masked by dead code analysis changes
9eb9fa6d7db Revert "Rollup merge of rust-lang#127107 - mu001999-contrib:dead/enhance-2, r=pnkfelix"
975dc19795e Rollup merge of rust-lang#128368 - nnethercote:rustfmt-tweaks, r=cuviper
0ee09fe87cf Rollup merge of rust-lang#128303 - NobodyXu:specialise-for-pipe, r=cuviper
1967a123728 Rollup merge of rust-lang#127586 - zachs18:more-must-use, r=cuviper
fc53324c54d Rollup merge of rust-lang#126704 - sayantn:sha, r=Amanieu
74dd96fbea9 chore: refactor backtrace style in panic
0e4358de84e Auto merge of rust-lang#128528 - workingjubilee:you-dont-need-to-see-this-cpuid-move-along, r=Amanieu
9fa74abcf83 Move the standard library to a separate workspace
e13d132801a Auto merge of rust-lang#128254 - Amanieu:orig-binary-search, r=tgross35
05d8d7c0765 Implement `UncheckedIterator` directly for `RepeatN`
a5fa13e131b Rollup merge of rust-lang#128491 - c410-f3r:unlock-rfc-2011, r=workingjubilee
28e4d22aec0 Rollup merge of rust-lang#128453 - RalfJung:raw_eq, r=saethlin
db770c6262d std: Remove has_cpuid
39aad04eaaf time.rs: remove "Basic usage text"
7df583ccfb3 Dogfood
cb110515265 Add the `sha512`, `sm3` and `sm4` target features
86ea79fb335 Fix mutability in doc tests for `BTreeSet` cursors
c7be27f744a Introduce `Cursor`/`CursorMut`/`CursorMutKey` thrichotomy for `BTreeSet` like map API
8835b0ffaef Fix some uses of "map" instead of "set" in `BTreeSet` cursor API docs
07f64a8e22c Share `UnorderedKeyError` with `BTReeMap` for set API
f859e542648 Rollup merge of rust-lang#128499 - Konippi:refactor-backtrace-formatting, r=tgross35
fb966d2b046 Rollup merge of rust-lang#128497 - Bryanskiy:fix-dropck-doc, r=lcnr
ab00ae63d7a Rollup merge of rust-lang#128433 - hermit-os:hermit-unsafe_op_in_unsafe_fn, r=joboet
2614bd2ae16 chore: refactor backtrace formatting
a8a46595ff6 fix dropck documentation for `[T;0]` special-case
589c0a0e872 fix(os/hermit): `deny(unsafe_op_in_unsafe_fn)`
0260e47b16e fix(pal/hermit): `deny(unsafe_op_in_unsafe_fn)`
7bd6b11e0ad refactor(pal/hermit): make `ENV` a non-mutable static
32894e2b70e Rollup merge of rust-lang#128416 - maurer:remove-android-hack, r=tgross35
beb76c31275 Auto merge of rust-lang#128461 - matthiaskrgr:rollup-3dpp11g, r=matthiaskrgr
1e3976be11a Rollup merge of rust-lang#128162 - ChrisDenton:cleanup, r=joboet
cde45b0a077 Rollup merge of rust-lang#127567 - joboet:once_wait, r=Amanieu
06076429681 Fix docs for OnceLock::get_mut_or_init
da484175cbd raw_eq: using it on bytes with provenance is not UB (outside const-eval)
cc6f37ff93f std: fix busy-waiting in `Once::wait_force`, add more tests
6fd82f18f54 std: implement the `once_wait` feature
0c56873d90f Remove unneeded `pub(crate)`
787a1f7a2e6 Rollup merge of rust-lang#128388 - beetrees:f16-f128-slightly-improve-windows-abi, r=tgross35
e3a4ed3406a Rollup merge of rust-lang#128387 - liigo:patch-14, r=tgross35
8b7f4ee6e3d refactor(pal/hermit): use default impl of `GlobalAlloc::alloc_zeroed`
c3370198cca refactor(pal/hermit): return `!` to satisfy rust-analyzer
7aafdcf2fa2 android: Remove libstd hacks for unsupported Android APIs
ba65c6c88c8 Move Windows implementation of anon pipe
176508ce960 Match LLVM ABI in `extern "C"` functions for `f128` on Windows
85e4ba09e56 Cleanup sys module to match house style
ddff2b608a9 Auto merge of rust-lang#128083 - Mark-Simulacrum:bump-bootstrap, r=albertlarsan68
e4b0e6d427b Rewrite binary search implementation
556dc6028e1 More detailed note to deprecate ONCE_INIT
440ec835e8f Auto merge of rust-lang#128378 - matthiaskrgr:rollup-i3qz9uo, r=matthiaskrgr
a50fe577e5d Auto merge of rust-lang#128250 - Amanieu:select_unpredictable, r=nikic
47f9d6175ee Rollup merge of rust-lang#128315 - zetanumbers:psvita-unsafe-in-unsafe, r=workingjubilee
f70ce7f3e03 Auto merge of rust-lang#128234 - jcsp:retain-empty-case, r=tgross35
93b2f7c4e88 Insert some blank lines.
db0222e3e80 Move a comment.
cc96f3e2d19 Stabilize offset_of_nested
618fdd536b5 Auto merge of rust-lang#128334 - matthiaskrgr:rollup-nhxdt0c, r=matthiaskrgr
e088cb1bcd7 Rollup merge of rust-lang#128333 - RalfJung:miri-sync, r=RalfJung
1ea0493512b Rollup merge of rust-lang#128307 - ojeda:unescaped_backticks, r=GuillaumeGomez
5d510999d8a Optimize empty case in Vec::retain
f2bcbecd66e Auto merge of rust-lang#125016 - nicholasbishop:bishop-cb-112, r=tgross35
7a43febb9b1 Rollup merge of rust-lang#128310 - kmicklas:btree-map-peek-next-docs, r=tgross35
03e5078d0f6 Rollup merge of rust-lang#128055 - workingjubilee:deny-unsafe-ops-in-sys-personality-dwarf-eh, r=Amanieu
f9befad9f51 Rollup merge of rust-lang#109174 - soerenmeier:cursor_fns, r=dtolnay
ed7d02fcc9b Update compiler_builtins to 0.1.114
80254cd2f12 Warn on `rustdoc::unescaped_backticks` for `core/alloc/std/test/proc_macro`
c8db8ead903 Remove spurious backticks detected by `rustdoc::unescaped_backticks`
d1d4fb32943 Reformat `use` declarations.
3ec244feaeb Replace `io::Cursor::{remaining_slice, is_empty}` with `io::Cursor::{split, split_mut}`
abc611ff511 step cfg(bootstrap)
78cd7797193 Update CURRENT_RUSTC_VERSION
70927dcd034 Add forbid(unsafe_op_in_unsafe_fn)
06a22c946e3 Rollup merge of rust-lang#128240 - mbrubeck:patch-3, r=joboet
604d6183e4d Rollup merge of rust-lang#128228 - slanterns:const_waker, r=dtolnay,oli-obk
2a70839bf8f Rollup merge of rust-lang#128103 - folkertdev:unsigned-int-is-multiple-of, r=Amanieu
058f1d3e3a7 Rollup merge of rust-lang#127765 - bitfield:fix_stdlib_doc_nits, r=dtolnay
9a6c84e26c1 fix: psvita's std code
5119266b79c Force LLVM to use CMOV for binary search
d6b6e639162 stabilize const_waker
8e4f58a6520 Add missing periods on `BTreeMap` cursor `peek_next` docs
458b9b07517 Implement cursors for `BTreeSet`
02bf0de46e4 Enable `std::io::copy` specialisation for `std::pipe::{PipeReader, PipeWriter}`
1f83bf3100e Rollup merge of rust-lang#128282 - pitaj:nonzero_bitwise, r=workingjubilee
357ff7a0265 Rollup merge of rust-lang#128279 - slanterns:is_sorted, r=dtolnay
fcbdcae5542 stabilize `is_sorted`
c47f8bdd4f5 bitwise and bytewise methods on `NonZero`
4ea98d76cfd Rollup merge of rust-lang#128259 - sunshowers:msg-nosignal, r=Mark-Simulacrum
d6f970a682d Rollup merge of rust-lang#125897 - RalfJung:from-ref, r=Amanieu
339f7567cf0 Auto merge of rust-lang#128255 - stepancheg:doc-shl, r=scottmcm
0d6a7dd333b Merge from rustc
a66bc798ecd Auto merge of rust-lang#127946 - tgross35:fmt-builders-set-result, r=cuviper
2986bfed613 [illumos/solaris] set MSG_NOSIGNAL while writing to sockets
3e854937500 Document int.checked_shl(BITS - 1)
59f3fefb4cb Rollup merge of rust-lang#128235 - harryscholes:fix-iterator-filter-docs, r=tgross35
a2dbfd338e9 Rollup merge of rust-lang#124941 - Skgland:stabilize-const-int-from-str, r=dtolnay
5b78bae1394 Add links from `assert_eq!` docs to `debug_assert_eq!`, etc.
a0f135d76af Always set `result` during `finish()` in debug builders
bd11b3dcc6d Fix  docs
22ce603b463 Auto merge of rust-lang#128165 - saethlin:optimize-clone-shims, r=compiler-errors
fb7d2a81c80 Fix doc nits
a1528206ab5 Rollup merge of rust-lang#128170 - saethlin:clone-fn, r=compiler-errors
0d636140614 Merge from rustc
cb8f69be7aa Rollup merge of rust-lang#128211 - juliusl:pr/align-change-time, r=tgross35
ba0582bf6c4 Rollup merge of rust-lang#128150 - BoxyUwU:std_only_sized_const_params, r=workingjubilee
30cfde4b97a Rollup merge of rust-lang#127950 - nnethercote:rustfmt-skip-on-use-decls, r=cuviper
8488ae6d29f Make Clone::clone a lang item
1342ef157c3 fix: compilation issue w/ refactored type
92c0ad77d5d Let InstCombine remove Clone shims inside Clone shims
c788415b025 Stop using `unsized_const_parameters` in core/std
ef4d4a039fe Auto merge of rust-lang#128195 - matthiaskrgr:rollup-195dfdf, r=matthiaskrgr
5b6c1e1ad32 Rollup merge of rust-lang#128137 - GrigorenkoPV:cstr-derive, r=dtolnay
aaeac06292c Rollup merge of rust-lang#127999 - ChrisDenton:arm32, r=Amanieu
ea3a99f0fc7 Rollup merge of rust-lang#128158 - workingjubilee:unsafe-wrap-personality-gcc, r=ChrisDenton
886fe5b7f53 Rollup merge of rust-lang#127300 - biabbas:fix_connect_timeout, r=tgross35
b889a1defa7 CStr: derive PartialEq, Eq; add test for Ord
3a181105a62 In connect timeout, read readiness of socket for vxworks. Check pollhup or pollerr for refused connections in linux
c4ee91f1305 Merge from rustc
244d8430769 std: update comments on gcc personality fn
d252b6b475b std: unsafe-wrap gcc::rust_eh_personality and impl
09bda4f2acb Rollup merge of rust-lang#128135 - joboet:reduplicate_tls, r=tgross35
a4c88bc2fbb Rollup merge of rust-lang#128046 - GrigorenkoPV:90435, r=tgross35
2614d86fcb4 Rollup merge of rust-lang#126548 - rik86189:issue-88264-fix, r=tgross35
75a178fdfa7 Rollup merge of rust-lang#126042 - davidzeng0:master, r=Amanieu
1e118aec933 Rollup merge of rust-lang#128131 - ChrisDenton:stuff, r=workingjubilee
cea2ca9af78 Rollup merge of rust-lang#128120 - compiler-errors:async-fn-name, r=oli-obk
92e3688370a Rollup merge of rust-lang#127733 - GrigorenkoPV:don't-forget, r=Amanieu
9b1cffdc1be Rollup merge of rust-lang#127480 - biabbas:vxworks, r=workingjubilee
2632261f008 Rollup merge of rust-lang#127252 - fitzgen:edge-cases-for-bitwise-operations, r=m-ou-se
b0d74144ae4 Rollup merge of rust-lang#126152 - RalfJung:size_of_val_raw, r=saethlin
6d0b7146359 Improved clarity of documentation for std::fs::create_dir_all
eb79e096922 std: use duplicate thread local state in tests
8456a976820 Forbid unsafe_op_in_unsafe_fn in sys/pal/windows
5a9fb1fc194 Import `core::ffi::c_void` in more places
16450f7b3e9 Merge from rustc
697c717b542 Add chroot unsupported implementation for VxWorks
6242470207d Rollup merge of rust-lang#128106 - hallfox:patch-1, r=ChrisDenton
de086ea59d4 Rollup merge of rust-lang#128092 - ChrisDenton:wrappers, r=workingjubilee
ccba33ca2dc Rollup merge of rust-lang#128043 - safinaskar:primitive, r=workingjubilee
a069998a10d Rollup merge of rust-lang#127481 - a1phyr:pattern_gat, r=Amanieu
bc7345c7866 Rollup merge of rust-lang#126770 - wr7:master, r=Amanieu
21f6b6516e2 Rollup merge of rust-lang#125962 - Coekjan:const-binary-heap, r=Amanieu
eee5bbaed57 Auto merge of rust-lang#127153 - NobodyXu:pipe, r=ChrisDenton
fd3a45fc3f9 Gate AsyncFn* under async_closure feature
0374ea22cab Add elem_offset and related methods
2b3eacb22c6 library/core/src/primitive.rs: small doc fix
45f80e6b25b Fix return type of FileAttr methods on AIX target
6cabb65c3fa add `is_multiple_of` for unsigned integer types
4c4a93a480e Initial implementation of anonymous_pipe
63d29970101 Update process vxworks, set default stack size of 256 Kib for vxworks. User can set the stack size using RUST_MIN_STACK, with min size of libc::PTHREAD_STACK_MIN(4kib)
ee8604174b0 Rollup merge of rust-lang#128089 - workingjubilee:commonly-wrapped-to-make-safe, r=ChrisDenton
ad9a52dcb35 Rollup merge of rust-lang#125834 - workingjubilee:weaken-thir-unsafeck-for-addr-of-static-mut, r=compiler-errors
642c69bbe40 Remove wrapper functions from c.rs
de2a0378391 std: Unsafe-wrap backtrace code held in-common
155aef9d64b std: Unsafe-wrap alloc code held in-common
bee0155d119 Cfg disable on_broken_pipe_flag_used() for vxworks
227b5afa55e Disable dirfd for vxworks, Return unsupported error from set_times and lchown for vxworks
22a6797af81 Allow unused unsafe for vxworks in read_at and write at
8be45a9e6a7 Docs for core::primitive: mention that "core" can be shadowed, too, so we should write "::core"
c039ee8ff7e library: vary unsafety in bootstrapping for SEH
6765b971f38 std: unsafe-wrap personality::dwarf::eh
7ae76f0ee2d Rollup merge of rust-lang#128008 - weiznich:fix/121521, r=lcnr
323e962d2cd Rollup merge of rust-lang#127996 - ian-h-chamberlain:fix/horizon-warnings-unsafe-in-unsafe, r=tgross35
ae6187f170c Rollup merge of rust-lang#127415 - AljoschaMeyer:master, r=dtolnay
d6a36f520f5 Use given allocator instad of Global
d0bc9a0ec5d Start using `#[diagnostic::do_not_recommend]` in the standard library
ba43261b233 Rollup merge of rust-lang#127583 - Nilstrieb:invalid-utf8, r=joboet
0727e53d393 Fix warnings when checking armv6k-nintendo-3ds
bbe4da839fa Fix some `#[cfg_attr(not(doc), repr(..))]`
321dbf82a78 Deal with invalid UTF-8 from `gai_strerror`
6aa00e1eece std::thread: available_parallelism implementation for vxWorks proposal.
2fff48df757 Auto merge of rust-lang#127722 - BoxyUwU:new_adt_const_params_limitations, r=compiler-errors
d7770e9cca2 Rollup merge of rust-lang#128005 - ChrisDenton:msvc-include, r=joboet
8fdee233d27 Rollup merge of rust-lang#127734 - ChrisDenton:netc, r=Mark-Simulacrum
3b2536ec206 Remove _tls_used hack
07dbb381321 Rollup merge of rust-lang#127873 - workingjubilee:forbid-unsafe-ops-for-kmc-solid, r=Amanieu
bd262955725 Rollup merge of rust-lang#127843 - workingjubilee:break-up-big-ass-stack-overflow-fn, r=joboet
00b4f61ec49 Inject win arm32 shims into metadata generation
2b628674392 Rollup merge of rust-lang#127918 - ChrisDenton:thread-name-string, r=joboet
a077eb1965c Rollup merge of rust-lang#123196 - Ayush1325:uefi-process, r=joboet
eb09be43d35 std: forbid unwrapped unsafe in unsupported_backslash
dcb98546d31 kmc-solid: forbid(unsafe_op_in_unsafe_fn)
845a2f78382 Auto merge of rust-lang#127982 - matthiaskrgr:rollup-nzyvphj, r=matthiaskrgr
00d6fc4cfef Rollup merge of rust-lang#127978 - nyurik:lib-refs, r=workingjubilee
4d8afcdd44b Avoid ref when using format! for perf
9f20a0f28ba Rollup merge of rust-lang#126199 - ivan-shrimp:nonzero_isqrt, r=tgross35
f06530cc0c3 Rollup merge of rust-lang#112328 - juliusl:pr/windows-add-change-time, r=ChrisDenton
8d5cf50b19d uefi: process: Fixes from PR
c6cb67c41a3 uefi: process: Final Touchups
afe1ef08b0e uefi: process: Add CommandArgs support
ef6b1730a13 uefi: process: Add support for args
1991fe38c57 uefi: process Implement inherit
24a95828625 uefi: process: Add null protocol
36a0e1e01c8 uefi: process: Add stderr support
b712e740ca4 uefi: process: Add support to capture stdout
e6eeb4ee295 uefi: Add process
f3b1c8a63e4 improve safety comment
93489988c77 add `NonZero<uN>::isqrt`
edc4cdc351b Use `#[rustfmt::skip]` on some `use` groups to prevent reordering.
489f1ef8747 unix: acquire-load NEED_ALTSTACK
9e11e01d38f unix: Unsafe-wrap stack_overflow::{drop,make}_handler
72c7444faf0 unix: Unsafe-wrap stack_overflow::cleanup
33a32f20bfd unix: lift init of sigaltstack before sigaction
9fb6e4958f7 unix: Unsafe-wrap stack_overflow::signal_handler
c99ebd411b7 Rollup merge of rust-lang#127594 - c6c7:fuchsia-status-code-match-arm, r=tmandry
83782615519 Move ThreadName conversions to &cstr/&str
68e23910a05 Style change
16bce8a458a Make `Thread::new_inner` a safe function
d1d98933f8f Rollup merge of rust-lang#127748 - scottmcm:option_len, r=joboet
b0c85badd9f Rollup merge of rust-lang#124881 - Sp00ph:reentrant_lock_tid, r=joboet
7e218501a06 Update `ReentrantLock` implementation, add `CURRENT_ID` thread local.
c10a929ac5e Safely enforce thread name requirements
cc4ed954619 Rollup merge of rust-lang#127077 - tbu-:pr_doc_fd_to_owned, r=workingjubilee
37d7bff7bb1 Rollup merge of rust-lang#127861 - Kriskras99:patch-1, r=tgross35
3d50720567e Rollup merge of rust-lang#127859 - RalfJung:ptr-dyn-metadata, r=scottmcm
1f3311b800b Rollup merge of rust-lang#127845 - workingjubilee:actually-break-up-big-ass-stack-overflow-fn, r=joboet
557859328cb Auto merge of rust-lang#127865 - matthiaskrgr:rollup-8m49dlg, r=matthiaskrgr
54728b12a9f feat: adding ext that returns change_time for Windows
b164bab985b Auto merge of rust-lang#125942 - timokroeger:windows-once-futex, r=ChrisDenton
0eda3a36123 Rollup merge of rust-lang#127337 - celinval:intrinsics-fallback, r=oli-obk
ed3c6d115e4 Mention how you can go from `BorrowedFd` to `OwnedFd` and back
455bd5705fb Make language around `ToOwned` for `BorrowedFd` more precise
ab7a0d4d6a5 Document the column numbers for the dbg! macro
89cd225caaa ptr::metadata: update comment on vtable_ptr work-around
51e54a4f5de ptr::metadata: avoid references to extern types
be0c06bc63e Split part of `adt_const_params` into `unsized_const_params`
857ed93c04e Forbid `!Sized` types and references
aedc16cadfe unix: unsafe-wrap install_main_guard_default
4db3aa1e628 unix: clean up install_main_guard_freebsd
d167f00072d unix: stack_start_aligned is a safe fn
27b79e6e1f7 unix: split stack_overflow::install_main_guard by os
d50143fddb9 Update name of Windows abort constant to match platform documentation
cbaa8317349 Add match arm for Fuchsia status code upon an abort in a test
f15715f3e48 lib: replace some `mem::forget`'s with `ManuallyDrop`
9bbf09d3d07 Windows: move BSD socket shims to netc
d76c965affa Remove generic lifetime parameter of trait `Pattern`
ad3db57a529 Use Option's discriminant as its size hint
3b86ae3449f Explicitly ignore `into_raw_handle()` using `let _ =` in sys/pal/windows.
1cb5354fc6c Add `must_use` to IntoRawFd/IntoRawSocket/IntoRawHandle's methods.
697377abf32 Clarify/add `must_use` messages for more `into_raw*` functions of `alloc` types.
a7bec568626 size_of_val_raw: for length 0 this is safe to call
39c4daabd50 Reset sigpipe not supported for vxworks
ca537d2cb33 Fix them doc examples some more
be23cef3a42 Fix doc examples
8d0199656c4 Run formatter on alloc/src/boxed.rs
c3b602af8ce Add missing try_new_uninit_slice_in and try_new_zeroed_slice_in
54875740eef Document safety of a few intrinsics
87fcd2f5c73 Move a few intrinsics to use Rust abi
6b549baafd8 mark `can_not_overflow` as `#[rustc_const_stable(...)]`
259c058b9f7 stabilize `const_int_from_str`
538fe8146ef Add edge-case examples to `{count,leading,trailing}_{ones,zeros}` methods
5fc66ddb6d3 Implement `unsigned_signed_diff`
dbbb4ab477a less garbage, more examples
4952644d73e update tracking issue for `const_binary_heap_new_in`
33389b0e051 more explicitly state the basic rules of working with the obtained raw pointers
395ad9f8afc Windows: Use futex implementation for `Once`
7953644ecec from_ref, from_mut: clarify domain of quantification

git-subtree-dir: library
git-subtree-split: 9cc3bc6add336a695c0570fb8655164ac96cc365
@gendx
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gendx commented Aug 16, 2024

This looks like a great intrinsic, that on paper could be applicable to a variety of domains (e.g. cryptography, as it corresponds to what crates like subtle or cmov attempt to do). However, I'm wondering what guarantees it really offers in terms of "forcing LLVM to use CMOV"?

I've tried the following simple functions, and it seems that although the unpredictable annotation is indeed present in the IR, LLVM optimizes away most operations (except the trivial standalone select_unpredictable): https://godbolt.org/z/GbE71z3dd

Is it intended? And if so, in which contexts is this intrinsic applicable?

#![feature(core_intrinsics)]

use std::intrinsics::select_unpredictable;

#[no_mangle]
pub fn baseline(p: bool, x: i32, y: i32) -> i32 {
    select_unpredictable(p, x, y)
}

#[no_mangle]
pub fn foo(x: i32, y: i32) -> i32 {
    select_unpredictable(false, x, y)
}

#[no_mangle]
pub fn bar(x: i32, y: i32) -> i32 {
    select_unpredictable(true, x, y)
}

#[no_mangle]
pub fn add(p: bool, x: i32, y: i32) -> i32 {
    select_unpredictable(p, x, y) + select_unpredictable(!p, x, y)
}

LLVM IR: only the baseline isn't optimized:

define noundef i32 @baseline(i1 noundef zeroext %p, i32 noundef %x, i32 noundef %y) unnamed_addr {
start:
  %0 = select i1 %p, i32 %x, i32 %y, !unpredictable !11
  ret i32 %0
}

define noundef i32 @foo(i32 noundef %x, i32 noundef returned %y) unnamed_addr {
start:
  ret i32 %y
}

define noundef i32 @bar(i32 noundef returned %x, i32 noundef %y) unnamed_addr {
start:
  ret i32 %x
}

define noundef i32 @add(i1 noundef zeroext %p, i32 noundef %x, i32 noundef %y) unnamed_addr {
start:
  %_0 = add i32 %y, %x
  ret i32 %_0
}

@nikic
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Contributor

nikic commented Aug 16, 2024

@gendx This intrinsic is a pure optimization hint. It does not carry any guarantees and is unsuitable for cryptographic use.

Is it intended? And if so, in which contexts is this intrinsic applicable?

As the name and description suggests: If the condition is unpredictable, and introducing a branch on it would degrade performance.

carolynzech added a commit to carolynzech/verify-rust-std that referenced this pull request Aug 16, 2024
9cc3bc6add3 custom MIR: add support for tail calls
5674d1c07e5 Auto merge of rust-lang#128673 - matthiaskrgr:rollup-gtvpkm7, r=matthiaskrgr
deb1d7576df Rollup merge of rust-lang#128619 - glandium:last_chunk, r=scottmcm
6449537a625 Rollup merge of rust-lang#128609 - swenson:smaller-faster-dragon, r=Amanieu
acb2c303c36 Rollup merge of rust-lang#128026 - devnexen:available_parallelism_vxworks, r=Mark-Simulacrum
89fe6dfa6b9 Rollup merge of rust-lang#128309 - kmicklas:btreeset-cursor, r=Amanieu
313484bb62c Correct the const stabilization of `<[T]>::last_chunk`
22e026b048c Auto merge of rust-lang#128534 - bjorn3:split_stdlib_workspace, r=Mark-Simulacrum
18136032131 Rollup merge of rust-lang#128526 - tshepang:patch-1, r=Amanieu
e8a1a4151ee Auto merge of rust-lang#128466 - sayantn:stdarch-update, r=tgross35
2adf9da42a3 Update stdarch
dc85bdb60ce Chore: add `x86_amx_intrinsics` feature flag to `core/lib.rs` and remove `issue-120720-reduce-nan.rs`
e88b04d135d Rollup merge of rust-lang#128551 - Konippi:refactor-backtrace-style-in-panic, r=tgross35
43a1e939ebe Rollup merge of rust-lang#128530 - scottmcm:repeat-n-unchecked, r=joboet
47df194eec6 Remove unnecessary constants from flt2dec dragon
0b5f1b8406f Auto merge of rust-lang#128404 - compiler-errors:revert-dead-code-changes, r=pnkfelix
35cd95f1edb Suppress new false-negatives that were masked by dead code analysis changes
9eb9fa6d7db Revert "Rollup merge of rust-lang#127107 - mu001999-contrib:dead/enhance-2, r=pnkfelix"
975dc19795e Rollup merge of rust-lang#128368 - nnethercote:rustfmt-tweaks, r=cuviper
0ee09fe87cf Rollup merge of rust-lang#128303 - NobodyXu:specialise-for-pipe, r=cuviper
1967a123728 Rollup merge of rust-lang#127586 - zachs18:more-must-use, r=cuviper
fc53324c54d Rollup merge of rust-lang#126704 - sayantn:sha, r=Amanieu
74dd96fbea9 chore: refactor backtrace style in panic
0e4358de84e Auto merge of rust-lang#128528 - workingjubilee:you-dont-need-to-see-this-cpuid-move-along, r=Amanieu
9fa74abcf83 Move the standard library to a separate workspace
e13d132801a Auto merge of rust-lang#128254 - Amanieu:orig-binary-search, r=tgross35
05d8d7c0765 Implement `UncheckedIterator` directly for `RepeatN`
a5fa13e131b Rollup merge of rust-lang#128491 - c410-f3r:unlock-rfc-2011, r=workingjubilee
28e4d22aec0 Rollup merge of rust-lang#128453 - RalfJung:raw_eq, r=saethlin
db770c6262d std: Remove has_cpuid
39aad04eaaf time.rs: remove "Basic usage text"
7df583ccfb3 Dogfood
cb110515265 Add the `sha512`, `sm3` and `sm4` target features
86ea79fb335 Fix mutability in doc tests for `BTreeSet` cursors
c7be27f744a Introduce `Cursor`/`CursorMut`/`CursorMutKey` thrichotomy for `BTreeSet` like map API
8835b0ffaef Fix some uses of "map" instead of "set" in `BTreeSet` cursor API docs
07f64a8e22c Share `UnorderedKeyError` with `BTReeMap` for set API
f859e542648 Rollup merge of rust-lang#128499 - Konippi:refactor-backtrace-formatting, r=tgross35
fb966d2b046 Rollup merge of rust-lang#128497 - Bryanskiy:fix-dropck-doc, r=lcnr
ab00ae63d7a Rollup merge of rust-lang#128433 - hermit-os:hermit-unsafe_op_in_unsafe_fn, r=joboet
2614bd2ae16 chore: refactor backtrace formatting
a8a46595ff6 fix dropck documentation for `[T;0]` special-case
589c0a0e872 fix(os/hermit): `deny(unsafe_op_in_unsafe_fn)`
0260e47b16e fix(pal/hermit): `deny(unsafe_op_in_unsafe_fn)`
7bd6b11e0ad refactor(pal/hermit): make `ENV` a non-mutable static
32894e2b70e Rollup merge of rust-lang#128416 - maurer:remove-android-hack, r=tgross35
beb76c31275 Auto merge of rust-lang#128461 - matthiaskrgr:rollup-3dpp11g, r=matthiaskrgr
1e3976be11a Rollup merge of rust-lang#128162 - ChrisDenton:cleanup, r=joboet
cde45b0a077 Rollup merge of rust-lang#127567 - joboet:once_wait, r=Amanieu
06076429681 Fix docs for OnceLock::get_mut_or_init
da484175cbd raw_eq: using it on bytes with provenance is not UB (outside const-eval)
cc6f37ff93f std: fix busy-waiting in `Once::wait_force`, add more tests
6fd82f18f54 std: implement the `once_wait` feature
0c56873d90f Remove unneeded `pub(crate)`
787a1f7a2e6 Rollup merge of rust-lang#128388 - beetrees:f16-f128-slightly-improve-windows-abi, r=tgross35
e3a4ed3406a Rollup merge of rust-lang#128387 - liigo:patch-14, r=tgross35
8b7f4ee6e3d refactor(pal/hermit): use default impl of `GlobalAlloc::alloc_zeroed`
c3370198cca refactor(pal/hermit): return `!` to satisfy rust-analyzer
7aafdcf2fa2 android: Remove libstd hacks for unsupported Android APIs
ba65c6c88c8 Move Windows implementation of anon pipe
176508ce960 Match LLVM ABI in `extern "C"` functions for `f128` on Windows
85e4ba09e56 Cleanup sys module to match house style
ddff2b608a9 Auto merge of rust-lang#128083 - Mark-Simulacrum:bump-bootstrap, r=albertlarsan68
e4b0e6d427b Rewrite binary search implementation
556dc6028e1 More detailed note to deprecate ONCE_INIT
440ec835e8f Auto merge of rust-lang#128378 - matthiaskrgr:rollup-i3qz9uo, r=matthiaskrgr
a50fe577e5d Auto merge of rust-lang#128250 - Amanieu:select_unpredictable, r=nikic
47f9d6175ee Rollup merge of rust-lang#128315 - zetanumbers:psvita-unsafe-in-unsafe, r=workingjubilee
f70ce7f3e03 Auto merge of rust-lang#128234 - jcsp:retain-empty-case, r=tgross35
93b2f7c4e88 Insert some blank lines.
db0222e3e80 Move a comment.
cc96f3e2d19 Stabilize offset_of_nested
618fdd536b5 Auto merge of rust-lang#128334 - matthiaskrgr:rollup-nhxdt0c, r=matthiaskrgr
e088cb1bcd7 Rollup merge of rust-lang#128333 - RalfJung:miri-sync, r=RalfJung
1ea0493512b Rollup merge of rust-lang#128307 - ojeda:unescaped_backticks, r=GuillaumeGomez
5d510999d8a Optimize empty case in Vec::retain
f2bcbecd66e Auto merge of rust-lang#125016 - nicholasbishop:bishop-cb-112, r=tgross35
7a43febb9b1 Rollup merge of rust-lang#128310 - kmicklas:btree-map-peek-next-docs, r=tgross35
03e5078d0f6 Rollup merge of rust-lang#128055 - workingjubilee:deny-unsafe-ops-in-sys-personality-dwarf-eh, r=Amanieu
f9befad9f51 Rollup merge of rust-lang#109174 - soerenmeier:cursor_fns, r=dtolnay
ed7d02fcc9b Update compiler_builtins to 0.1.114
80254cd2f12 Warn on `rustdoc::unescaped_backticks` for `core/alloc/std/test/proc_macro`
c8db8ead903 Remove spurious backticks detected by `rustdoc::unescaped_backticks`
d1d4fb32943 Reformat `use` declarations.
3ec244feaeb Replace `io::Cursor::{remaining_slice, is_empty}` with `io::Cursor::{split, split_mut}`
abc611ff511 step cfg(bootstrap)
78cd7797193 Update CURRENT_RUSTC_VERSION
70927dcd034 Add forbid(unsafe_op_in_unsafe_fn)
06a22c946e3 Rollup merge of rust-lang#128240 - mbrubeck:patch-3, r=joboet
604d6183e4d Rollup merge of rust-lang#128228 - slanterns:const_waker, r=dtolnay,oli-obk
2a70839bf8f Rollup merge of rust-lang#128103 - folkertdev:unsigned-int-is-multiple-of, r=Amanieu
058f1d3e3a7 Rollup merge of rust-lang#127765 - bitfield:fix_stdlib_doc_nits, r=dtolnay
9a6c84e26c1 fix: psvita's std code
5119266b79c Force LLVM to use CMOV for binary search
d6b6e639162 stabilize const_waker
8e4f58a6520 Add missing periods on `BTreeMap` cursor `peek_next` docs
458b9b07517 Implement cursors for `BTreeSet`
02bf0de46e4 Enable `std::io::copy` specialisation for `std::pipe::{PipeReader, PipeWriter}`
1f83bf3100e Rollup merge of rust-lang#128282 - pitaj:nonzero_bitwise, r=workingjubilee
357ff7a0265 Rollup merge of rust-lang#128279 - slanterns:is_sorted, r=dtolnay
fcbdcae5542 stabilize `is_sorted`
c47f8bdd4f5 bitwise and bytewise methods on `NonZero`
4ea98d76cfd Rollup merge of rust-lang#128259 - sunshowers:msg-nosignal, r=Mark-Simulacrum
d6f970a682d Rollup merge of rust-lang#125897 - RalfJung:from-ref, r=Amanieu
339f7567cf0 Auto merge of rust-lang#128255 - stepancheg:doc-shl, r=scottmcm
0d6a7dd333b Merge from rustc
a66bc798ecd Auto merge of rust-lang#127946 - tgross35:fmt-builders-set-result, r=cuviper
2986bfed613 [illumos/solaris] set MSG_NOSIGNAL while writing to sockets
3e854937500 Document int.checked_shl(BITS - 1)
59f3fefb4cb Rollup merge of rust-lang#128235 - harryscholes:fix-iterator-filter-docs, r=tgross35
a2dbfd338e9 Rollup merge of rust-lang#124941 - Skgland:stabilize-const-int-from-str, r=dtolnay
5b78bae1394 Add links from `assert_eq!` docs to `debug_assert_eq!`, etc.
a0f135d76af Always set `result` during `finish()` in debug builders
bd11b3dcc6d Fix  docs
22ce603b463 Auto merge of rust-lang#128165 - saethlin:optimize-clone-shims, r=compiler-errors
fb7d2a81c80 Fix doc nits
a1528206ab5 Rollup merge of rust-lang#128170 - saethlin:clone-fn, r=compiler-errors
0d636140614 Merge from rustc
cb8f69be7aa Rollup merge of rust-lang#128211 - juliusl:pr/align-change-time, r=tgross35
ba0582bf6c4 Rollup merge of rust-lang#128150 - BoxyUwU:std_only_sized_const_params, r=workingjubilee
30cfde4b97a Rollup merge of rust-lang#127950 - nnethercote:rustfmt-skip-on-use-decls, r=cuviper
8488ae6d29f Make Clone::clone a lang item
1342ef157c3 fix: compilation issue w/ refactored type
92c0ad77d5d Let InstCombine remove Clone shims inside Clone shims
c788415b025 Stop using `unsized_const_parameters` in core/std
ef4d4a039fe Auto merge of rust-lang#128195 - matthiaskrgr:rollup-195dfdf, r=matthiaskrgr
5b6c1e1ad32 Rollup merge of rust-lang#128137 - GrigorenkoPV:cstr-derive, r=dtolnay
aaeac06292c Rollup merge of rust-lang#127999 - ChrisDenton:arm32, r=Amanieu
ea3a99f0fc7 Rollup merge of rust-lang#128158 - workingjubilee:unsafe-wrap-personality-gcc, r=ChrisDenton
886fe5b7f53 Rollup merge of rust-lang#127300 - biabbas:fix_connect_timeout, r=tgross35
b889a1defa7 CStr: derive PartialEq, Eq; add test for Ord
3a181105a62 In connect timeout, read readiness of socket for vxworks. Check pollhup or pollerr for refused connections in linux
c4ee91f1305 Merge from rustc
244d8430769 std: update comments on gcc personality fn
d252b6b475b std: unsafe-wrap gcc::rust_eh_personality and impl
09bda4f2acb Rollup merge of rust-lang#128135 - joboet:reduplicate_tls, r=tgross35
a4c88bc2fbb Rollup merge of rust-lang#128046 - GrigorenkoPV:90435, r=tgross35
2614d86fcb4 Rollup merge of rust-lang#126548 - rik86189:issue-88264-fix, r=tgross35
75a178fdfa7 Rollup merge of rust-lang#126042 - davidzeng0:master, r=Amanieu
1e118aec933 Rollup merge of rust-lang#128131 - ChrisDenton:stuff, r=workingjubilee
cea2ca9af78 Rollup merge of rust-lang#128120 - compiler-errors:async-fn-name, r=oli-obk
92e3688370a Rollup merge of rust-lang#127733 - GrigorenkoPV:don't-forget, r=Amanieu
9b1cffdc1be Rollup merge of rust-lang#127480 - biabbas:vxworks, r=workingjubilee
2632261f008 Rollup merge of rust-lang#127252 - fitzgen:edge-cases-for-bitwise-operations, r=m-ou-se
b0d74144ae4 Rollup merge of rust-lang#126152 - RalfJung:size_of_val_raw, r=saethlin
6d0b7146359 Improved clarity of documentation for std::fs::create_dir_all
eb79e096922 std: use duplicate thread local state in tests
8456a976820 Forbid unsafe_op_in_unsafe_fn in sys/pal/windows
5a9fb1fc194 Import `core::ffi::c_void` in more places
16450f7b3e9 Merge from rustc
697c717b542 Add chroot unsupported implementation for VxWorks
6242470207d Rollup merge of rust-lang#128106 - hallfox:patch-1, r=ChrisDenton
de086ea59d4 Rollup merge of rust-lang#128092 - ChrisDenton:wrappers, r=workingjubilee
ccba33ca2dc Rollup merge of rust-lang#128043 - safinaskar:primitive, r=workingjubilee
a069998a10d Rollup merge of rust-lang#127481 - a1phyr:pattern_gat, r=Amanieu
bc7345c7866 Rollup merge of rust-lang#126770 - wr7:master, r=Amanieu
21f6b6516e2 Rollup merge of rust-lang#125962 - Coekjan:const-binary-heap, r=Amanieu
eee5bbaed57 Auto merge of rust-lang#127153 - NobodyXu:pipe, r=ChrisDenton
fd3a45fc3f9 Gate AsyncFn* under async_closure feature
0374ea22cab Add elem_offset and related methods
2b3eacb22c6 library/core/src/primitive.rs: small doc fix
45f80e6b25b Fix return type of FileAttr methods on AIX target
6cabb65c3fa add `is_multiple_of` for unsigned integer types
4c4a93a480e Initial implementation of anonymous_pipe
63d29970101 Update process vxworks, set default stack size of 256 Kib for vxworks. User can set the stack size using RUST_MIN_STACK, with min size of libc::PTHREAD_STACK_MIN(4kib)
ee8604174b0 Rollup merge of rust-lang#128089 - workingjubilee:commonly-wrapped-to-make-safe, r=ChrisDenton
ad9a52dcb35 Rollup merge of rust-lang#125834 - workingjubilee:weaken-thir-unsafeck-for-addr-of-static-mut, r=compiler-errors
642c69bbe40 Remove wrapper functions from c.rs
de2a0378391 std: Unsafe-wrap backtrace code held in-common
155aef9d64b std: Unsafe-wrap alloc code held in-common
bee0155d119 Cfg disable on_broken_pipe_flag_used() for vxworks
227b5afa55e Disable dirfd for vxworks, Return unsupported error from set_times and lchown for vxworks
22a6797af81 Allow unused unsafe for vxworks in read_at and write at
8be45a9e6a7 Docs for core::primitive: mention that "core" can be shadowed, too, so we should write "::core"
c039ee8ff7e library: vary unsafety in bootstrapping for SEH
6765b971f38 std: unsafe-wrap personality::dwarf::eh
7ae76f0ee2d Rollup merge of rust-lang#128008 - weiznich:fix/121521, r=lcnr
323e962d2cd Rollup merge of rust-lang#127996 - ian-h-chamberlain:fix/horizon-warnings-unsafe-in-unsafe, r=tgross35
ae6187f170c Rollup merge of rust-lang#127415 - AljoschaMeyer:master, r=dtolnay
d6a36f520f5 Use given allocator instad of Global
d0bc9a0ec5d Start using `#[diagnostic::do_not_recommend]` in the standard library
ba43261b233 Rollup merge of rust-lang#127583 - Nilstrieb:invalid-utf8, r=joboet
0727e53d393 Fix warnings when checking armv6k-nintendo-3ds
bbe4da839fa Fix some `#[cfg_attr(not(doc), repr(..))]`
321dbf82a78 Deal with invalid UTF-8 from `gai_strerror`
6aa00e1eece std::thread: available_parallelism implementation for vxWorks proposal.
2fff48df757 Auto merge of rust-lang#127722 - BoxyUwU:new_adt_const_params_limitations, r=compiler-errors
d7770e9cca2 Rollup merge of rust-lang#128005 - ChrisDenton:msvc-include, r=joboet
8fdee233d27 Rollup merge of rust-lang#127734 - ChrisDenton:netc, r=Mark-Simulacrum
3b2536ec206 Remove _tls_used hack
07dbb381321 Rollup merge of rust-lang#127873 - workingjubilee:forbid-unsafe-ops-for-kmc-solid, r=Amanieu
bd262955725 Rollup merge of rust-lang#127843 - workingjubilee:break-up-big-ass-stack-overflow-fn, r=joboet
00b4f61ec49 Inject win arm32 shims into metadata generation
2b628674392 Rollup merge of rust-lang#127918 - ChrisDenton:thread-name-string, r=joboet
a077eb1965c Rollup merge of rust-lang#123196 - Ayush1325:uefi-process, r=joboet
eb09be43d35 std: forbid unwrapped unsafe in unsupported_backslash
dcb98546d31 kmc-solid: forbid(unsafe_op_in_unsafe_fn)
845a2f78382 Auto merge of rust-lang#127982 - matthiaskrgr:rollup-nzyvphj, r=matthiaskrgr
00d6fc4cfef Rollup merge of rust-lang#127978 - nyurik:lib-refs, r=workingjubilee
4d8afcdd44b Avoid ref when using format! for perf
9f20a0f28ba Rollup merge of rust-lang#126199 - ivan-shrimp:nonzero_isqrt, r=tgross35
f06530cc0c3 Rollup merge of rust-lang#112328 - juliusl:pr/windows-add-change-time, r=ChrisDenton
8d5cf50b19d uefi: process: Fixes from PR
c6cb67c41a3 uefi: process: Final Touchups
afe1ef08b0e uefi: process: Add CommandArgs support
ef6b1730a13 uefi: process: Add support for args
1991fe38c57 uefi: process Implement inherit
24a95828625 uefi: process: Add null protocol
36a0e1e01c8 uefi: process: Add stderr support
b712e740ca4 uefi: process: Add support to capture stdout
e6eeb4ee295 uefi: Add process
f3b1c8a63e4 improve safety comment
93489988c77 add `NonZero<uN>::isqrt`
edc4cdc351b Use `#[rustfmt::skip]` on some `use` groups to prevent reordering.
489f1ef8747 unix: acquire-load NEED_ALTSTACK
9e11e01d38f unix: Unsafe-wrap stack_overflow::{drop,make}_handler
72c7444faf0 unix: Unsafe-wrap stack_overflow::cleanup
33a32f20bfd unix: lift init of sigaltstack before sigaction
9fb6e4958f7 unix: Unsafe-wrap stack_overflow::signal_handler
c99ebd411b7 Rollup merge of rust-lang#127594 - c6c7:fuchsia-status-code-match-arm, r=tmandry
83782615519 Move ThreadName conversions to &cstr/&str
68e23910a05 Style change
16bce8a458a Make `Thread::new_inner` a safe function
d1d98933f8f Rollup merge of rust-lang#127748 - scottmcm:option_len, r=joboet
b0c85badd9f Rollup merge of rust-lang#124881 - Sp00ph:reentrant_lock_tid, r=joboet
7e218501a06 Update `ReentrantLock` implementation, add `CURRENT_ID` thread local.
c10a929ac5e Safely enforce thread name requirements
cc4ed954619 Rollup merge of rust-lang#127077 - tbu-:pr_doc_fd_to_owned, r=workingjubilee
37d7bff7bb1 Rollup merge of rust-lang#127861 - Kriskras99:patch-1, r=tgross35
3d50720567e Rollup merge of rust-lang#127859 - RalfJung:ptr-dyn-metadata, r=scottmcm
1f3311b800b Rollup merge of rust-lang#127845 - workingjubilee:actually-break-up-big-ass-stack-overflow-fn, r=joboet
557859328cb Auto merge of rust-lang#127865 - matthiaskrgr:rollup-8m49dlg, r=matthiaskrgr
54728b12a9f feat: adding ext that returns change_time for Windows
b164bab985b Auto merge of rust-lang#125942 - timokroeger:windows-once-futex, r=ChrisDenton
0eda3a36123 Rollup merge of rust-lang#127337 - celinval:intrinsics-fallback, r=oli-obk
ed3c6d115e4 Mention how you can go from `BorrowedFd` to `OwnedFd` and back
455bd5705fb Make language around `ToOwned` for `BorrowedFd` more precise
ab7a0d4d6a5 Document the column numbers for the dbg! macro
89cd225caaa ptr::metadata: update comment on vtable_ptr work-around
51e54a4f5de ptr::metadata: avoid references to extern types
be0c06bc63e Split part of `adt_const_params` into `unsized_const_params`
857ed93c04e Forbid `!Sized` types and references
aedc16cadfe unix: unsafe-wrap install_main_guard_default
4db3aa1e628 unix: clean up install_main_guard_freebsd
d167f00072d unix: stack_start_aligned is a safe fn
27b79e6e1f7 unix: split stack_overflow::install_main_guard by os
d50143fddb9 Update name of Windows abort constant to match platform documentation
cbaa8317349 Add match arm for Fuchsia status code upon an abort in a test
f15715f3e48 lib: replace some `mem::forget`'s with `ManuallyDrop`
9bbf09d3d07 Windows: move BSD socket shims to netc
d76c965affa Remove generic lifetime parameter of trait `Pattern`
ad3db57a529 Use Option's discriminant as its size hint
3b86ae3449f Explicitly ignore `into_raw_handle()` using `let _ =` in sys/pal/windows.
1cb5354fc6c Add `must_use` to IntoRawFd/IntoRawSocket/IntoRawHandle's methods.
697377abf32 Clarify/add `must_use` messages for more `into_raw*` functions of `alloc` types.
a7bec568626 size_of_val_raw: for length 0 this is safe to call
39c4daabd50 Reset sigpipe not supported for vxworks
ca537d2cb33 Fix them doc examples some more
be23cef3a42 Fix doc examples
8d0199656c4 Run formatter on alloc/src/boxed.rs
c3b602af8ce Add missing try_new_uninit_slice_in and try_new_zeroed_slice_in
54875740eef Document safety of a few intrinsics
87fcd2f5c73 Move a few intrinsics to use Rust abi
6b549baafd8 mark `can_not_overflow` as `#[rustc_const_stable(...)]`
259c058b9f7 stabilize `const_int_from_str`
538fe8146ef Add edge-case examples to `{count,leading,trailing}_{ones,zeros}` methods
5fc66ddb6d3 Implement `unsigned_signed_diff`
dbbb4ab477a less garbage, more examples
4952644d73e update tracking issue for `const_binary_heap_new_in`
33389b0e051 more explicitly state the basic rules of working with the obtained raw pointers
395ad9f8afc Windows: Use futex implementation for `Once`
7953644ecec from_ref, from_mut: clarify domain of quantification

git-subtree-dir: library
git-subtree-split: 9cc3bc6add336a695c0570fb8655164ac96cc365
#[unstable(feature = "core_intrinsics", issue = "none")]
#[rustc_intrinsic]
#[rustc_nounwind]
#[miri::intrinsic_fallback_is_spec]
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Please ping @rust-lang/miri when using this attribute, so that we can have a look at the spec. :)

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