GVN: Elide more intermediate transmutes
We already skipped intermediate steps like `u32` or `i32` that support any (initialized) value.
This extends that to also allow skipping intermediate steps whose values are a superset of either the source or destination type. Most importantly, that means that `usize` → `NonZeroUsize` → `ptr::Alignment` and `ptr::Alignment` → `NonZeroUsize` → `usize` can skip the middle because `NonZeroUsize` is a superset of `Alignment`.
Then `Alignment::as_usize` is updated to take advantage of that and let us remove some more locals in a few places.
r? cjgillot
Remove duplicated code in `slice/index.rs`
Looks like `const fn` is far enough along now that we can just not have these two copies any more, and have one call the other.
thread::scope: document how join interacts with TLS destructors
Fixes https://github.com/rust-lang/rust/issues/116237 by documenting the current behavior regarding thread-local destructors as intended. (I'm not stoked about this, but documenting it is better than leaving it unclear.)
This also adds documentation for explicit `join` calls (both for scoped and regular threads), saying that those *will* wait for TLS destructors. That reflects my understanding of the current implementation, which calls `join` on the native thread handle. Are we okay with guaranteeing that? I think we should, so people have at least some chance of implementing "wait for all destructors" manually. This fixes https://github.com/rust-lang/rust/issues/127571.
Cc @rust-lang/libs-api
compiler-builtins: Remove the no-f16-f128 feature
This option was used to gate `f16` and `f128` when support across backends and targets was inconsistent. We now have the rustc builtin cfg `target_has_reliable{f16,f128}` which has taken over this usecase. Remove no-f16-f128 since it is now unused and redundant.
Tweak `SlicePartialEq` to allow MIR-inlining the `compare_bytes` call
rust-lang/rust#150265 disabled this because it was a net perf win, but let's see if we can tweak the structure of this to allow more inlining on this side while still not MIR-inlining the loop when it's not just `memcmp` and thus hopefully preserving the perf win.
This should also allow MIR-inlining the length check, which was previously blocked, and thus might allow some obvious non-matches to optimize away as well.
Add some clarifications and fixes for fmt syntax
This tries to clarify a few things regarding fmt syntax:
- The comment on `Parser::word` seems to be wrong, as that underscore-prefixed words are just fine. This was changed in https://github.com/rust-lang/rust/pull/66847.
- I struggled to follow the description of the width argument. It referred to a "second argument", but I don't know what second argument it is referring to (which is the first?). Either way, I rewrote the paragraph to try to be a little more explicit, and to use shorter sentences.
- The description of the precision argument wasn't really clear about the distinction of an Nth argument and a named argument. I added a sentence to try to emphasize the difference.
- `IDENTIFIER_OR_KEYWORD` was changed recently in https://github.com/rust-lang/reference/pull/2049 to include bare `_`. But fmt named arguments are not allowed to be a bare `_`.
std: move time implementations to `sys`
This is probably the most complex step of rust-lang/rust#117276 so far. Unfortunately, quite some of the internal time logic defined in the PAL is also used in other places like the filesystem code, so this isn't just a series of simple moves. I've left all that logic inside the PAL and only moved the actual `SystemTime`/`Instant` implementations.
While there are no functional changes, this PR also contains some slight code cleanups on Windows and Hermit, these are explained in the relevant commits.
For additional details see the individual commits, I've tried to make the messages as helpful as possible about what's going on.
- Adds vluti2 intrinsics
- Adds famin/famax intrinsics
- Adds vstl1(q) intrinsics
- Adds vldap1(q) intrinsics
- Excludes vldap1_lane_f64 as in testing it fails assert_intr. There seems to be some bad IR gen from rust.
- Adds vscale(q) intrinsics
- Adds new intrinsics to arm_intrinsics.json
- Had to be done manually as intrinsics are not yet on developer.arm.com
Last on the list: Hermit. Since I anticipate that Hermit will share the UNIX
implementation in the future, I've left `Timespec` in the PAL to maintain a
similar structure. Also, I noticed that some public `Instant` methods were
redefined on the internal `Instant`. But the networking code can just use the
public `Instant`, so I've removed them.
WASI and TEEOS share the UNIX implementation. Since `Timespec` lives in the
PAL, this means that the `#[path]` imports of `unix/time.rs` still remain for
these two, unfortunately. Maybe we'll solve that in the future by always
including the UNIX PAL for these remotely UNIXy platforms. But that's a story
for another time...
Now for UNIX: `Timespec` is also used for things like futex or `Condvar`
timeouts, so it stays in the PAL along with some related definitions.
Everything else is `SystemTime`- and `Instant`-specific, and is thus moved to
`sys::time`.
