Use a faster allocation size check in slice::from_raw_parts
I've been perusing through the codegen changes that result from turning on the standard library debug assertions. The previous check in here uses saturating arithmetic, which in my experience sometimes makes LLVM just fail to optimize things around the saturating operation.
Here is a demo of the codegen difference: https://godbolt.org/z/WMEqrjajW
Before:
```asm
example::len_check_old:
mov rax, rdi
mov ecx, 3
mul rcx
setno cl
test rax, rax
setns al
and al, cl
ret
example::len_check_old:
mov rax, rdi
mov ecx, 8
mul rcx
setno cl
test rax, rax
setns al
and al, cl
ret
```
After:
```asm
example::len_check_new:
movabs rax, 3074457345618258603
cmp rdi, rax
setb al
ret
example::len_check_new:
shr rdi, 60
sete al
ret
```
Running rustc-perf locally, this looks like up to a 4.5% improvement when `debug-assertions-std = true`.
Thanks ```@LegionMammal978``` (I think that's you?) for turning my idea into a much cleaner implementation.
r? ```@thomcc```
Diagnostic derives: allow specifying multiple alternative suggestions
This allows porting `span_suggestions()` to diagnostic structs.
Doesn't work for `multipart_suggestions()` because the rank would be reversed - the struct would specify multiple spans, each of which has multiple possible replacements, while `multipart_suggestions()` creates multiple possible replacements, each with multiple spans.
suggest type annotation for local statement initialed by ref expression
In a local statement with a type declaration, if a ref expression is used on the right side and not used on the left side, in addition to removing the `&` and `&mut` on the right side, we can add them on the left side alternatively
Fixes#102892
Add eval hack in `super_relate_consts` back
Partially reverts 01adb7e98d.
This extra eval call *still* needs to happen, for example, in `normalize_param_env_or_error` when a param-env predicate has an unnormalized constant, since the param-env candidates never get normalized during candidate assembly (everywhere else we can assume that they are normalized fully).
r? `@lcnr,` though I feel like I've assigned quite a few PRs to you in the last few days, so feel free to reassign to someone else familiar with this code if you're busy!
cc #103243 (fixes the issue, but don't want to auto-close that until a backport is performed).
5 commits in 071eeaf210708219a5a1b2c4728ca2f97df7f2ae..9210810d1fd7b51ae0439a0a363cc50e36963455
2022-10-22 01:17:55 +0000 to 2022-10-25 22:31:50 +0000
- Fix 410 gone response handling (rust-lang/cargo#11286)
- Fix inequality in "stale mtime" log messages (rust-lang/cargo#11281)
- doc(cargo-tree): mention it considering feature unification (rust-lang/cargo#11282)
- Improve the error message if `publish` is `false` or empty list (rust-lang/cargo#11280)
- Add test for deleted index entry (rust-lang/cargo#11278)
The change in opacity is inconsistent with most of rustdoc, which uses
default browser styles for the focus outline. Unfortunately, just using
the default focus outline here won't work, because it gets applied to
the summary itself instead of the pseudo-element "real button."
Assert if inference vars are leaking from `InferCtxt::fully_resolve`
`InferCtxt::fully_resolve` shouldn't return unresolved inference vars without us at least being aware of it, so make it an assertion now. This should only happen in cases where we used to be returning `ReEmpty`...
cc `@jackh726`
Split phase change from `MirPass`
The main goal here is to simplify the pass manager logic. `MirPass` no longer contains the `phase_change` method, and `run_passes` instead accepts an `Option<PhaseChange>`. The hope is that this addresses the comments (and maybe perf regression) from #99102 .
r? `@oli-obk` cc `@RalfJung`
This allows writing the following function signatures:
```rust
fn f0() -> impl Fn() -> impl Trait;
fn f3() -> &'static dyn Fn() -> impl Trait;
```
These signatures were already allowed for common traits and associated
types, there is no reason why `Fn*` traits should be special in this
regard.
