Rollup of 3 pull requests#152629
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JonathanBrouwer wants to merge 84 commits intorust-lang:mainfrom
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This moves all LLVM intrinsic handling out of the regular call path for cg_gcc and makes it easier to hook into this code for future cg_llvm changes.
…acro_transparency`
It's described as a "backwards compatibility hack to keep the diff small". Removing it requires only a modest amount of churn, and the resulting code is clearer without the invisible derefs.
…ics-generation Simplify intrinsics generation
Regenerate intrinsics
Move LTO to OngoingCodegen::join This will make it easier to in the future move all this code to link_binary. Follow up to rust-lang#147810 Part of rust-lang/compiler-team#908
This is the conceptual opposite of the rust-cold calling convention and
is particularly useful in combination with the new `explicit_tail_calls`
feature.
For relatively tight loops implemented with tail calling (`become`) each
of the function with the regular calling convention is still responsible
for restoring the initial value of the preserved registers. So it is not
unusual to end up with a situation where each step in the tail call loop
is spilling and reloading registers, along the lines of:
foo:
push r12
; do things
pop r12
jmp next_step
This adds up quickly, especially when most of the clobberable registers
are already used to pass arguments or other uses.
I was thinking of making the name of this ABI a little less LLVM-derived
and more like a conceptual inverse of `rust-cold`, but could not come
with a great name (`rust-cold` is itself not a great name: cold in what
context? from which perspective? is it supposed to mean that the
function is rarely called?)
Fix segfault related to __builtin_unreachable with inline asm
…bilee
add `simd_splat` intrinsic
Add `simd_splat` which lowers to the LLVM canonical splat sequence.
```llvm
insertelement <N x elem> poison, elem %x, i32 0
shufflevector <N x elem> v0, <N x elem> poison, <N x i32> zeroinitializer
```
Right now we try to fake it using one of
```rust
fn splat(x: u32) -> u32x8 {
u32x8::from_array([x; 8])
}
```
or (in `stdarch`)
```rust
fn splat(value: $elem_type) -> $name {
#[derive(Copy, Clone)]
#[repr(simd)]
struct JustOne([$elem_type; 1]);
let one = JustOne([value]);
// SAFETY: 0 is always in-bounds because we're shuffling
// a simd type with exactly one element.
unsafe { simd_shuffle!(one, one, [0; $len]) }
}
```
Both of these can confuse the LLVM optimizer, producing sub-par code. Some examples:
- rust-lang#60637
- rust-lang#137407
- rust-lang#122623
- rust-lang#97804
---
As far as I can tell there is no way to provide a fallback implementation for this intrinsic, because there is no `const` way of evaluating the number of elements (there might be issues beyond that, too). So, I added implementations for all 4 backends.
Both GCC and const-eval appear to have some issues with simd vectors containing pointers. I have a workaround for GCC, but haven't yet been able to make const-eval work. See the comments below.
Currently this just adds the intrinsic, it does not actually use it anywhere yet.
…ochenkov
abi: add a rust-preserve-none calling convention
This is the conceptual opposite of the rust-cold calling convention and is particularly useful in combination with the new `explicit_tail_calls` feature.
For relatively tight loops implemented with tail calling (`become`) each of the function with the regular calling convention is still responsible for restoring the initial value of the preserved registers. So it is not unusual to end up with a situation where each step in the tail call loop is spilling and reloading registers, along the lines of:
foo:
push r12
; do things
pop r12
jmp next_step
This adds up quickly, especially when most of the clobberable registers are already used to pass arguments or other uses.
I was thinking of making the name of this ABI a little less LLVM-derived and more like a conceptual inverse of `rust-cold`, but could not come with a great name (`rust-cold` is itself not a great name: cold in what context? from which perspective? is it supposed to mean that the function is rarely called?)
…2_12 Sync from rust 2026/02/12
…2_13 Sync from rust 2026/02/13
…update_cg_gcc_2026-02-14
…cc_2026-02-14, r=GuillaumeGomez Update GCC subtree cc @antoyo r? ghost
…, r=Mark-Simulacrum
Optimize indexing slices and strs with inclusive ranges
Instead of separately checking for `end == usize::MAX` and `end + 1 > slice.len()`, we can check for `end >= slice.len()`. Also consolidate all the str indexing related panic functions into a single function which reports the correct error depending on the arguments, as the slice indexing code already does.
The downside of all this is that the panic message is slightly less specific when trying to index with `[..=usize::MAX]`: instead of saying "attempted to index str up to maximum usize" it just says "end byte index {end} out of bounds". But this is a rare enough case that I think it is acceptable
…ark-Simulacrum Remove named lifetimes in some `PartialOrd` & `PartialEq` `impl`s Makes [the docs](https://doc.rust-lang.org/1.88.0/std/cmp/trait.PartialOrd.html#impl-PartialOrd%3CPathBuf%3E-for-Cow%3C'a,+Path%3E) way easier to look at, gets rid of a few `#[allow(unused_lifetimes)]`, and AFAICT is completely equivalent.
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Successful merges:
PartialOrd&PartialEqimpls #143575 (Remove named lifetimes in somePartialOrd&PartialEqimpls)r? @ghost
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