Simplify internals of {Rc,Arc}::default#152591
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alexcrichton wants to merge 1 commit intorust-lang:mainfrom
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Simplify internals of {Rc,Arc}::default#152591alexcrichton wants to merge 1 commit intorust-lang:mainfrom
{Rc,Arc}::default#152591alexcrichton wants to merge 1 commit intorust-lang:mainfrom
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This commit simplifies the internal implementation of `Default` for these two pointer types to have the same performance characteristics as before (a side effect of changes in 131460) while avoid use of internal private APIs of Rc/Arc. To preserve the same codegen as before some non-generic functions needed to be tagged as `#[inline]` as well, but otherwise the same IR is produced before/after this change. The motivation of this commit is I was studying up on the state of initialization of `Arc` and `Rc` and figured it'd be nicer to reduce the use of internal APIs and instead use public stable APIs where possible, even in the implementation itself.
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Feb 14, 2026
| @@ -30,8 +31,7 @@ pub fn new_uninit(x: u64) -> Arc<[u64; 1000]> { | |||
| // CHECK-LABEL: @new_uninit_slice | |||
| #[no_mangle] | |||
| pub fn new_uninit_slice(x: u64) -> Arc<[u64]> { | |||
| // CHECK: call alloc::sync::arcinner_layout_for_value_layout | |||
| // CHECK-NOT: call alloc::sync::arcinner_layout_for_value_layout | |||
| // CHECK-NOT: %[[B:.+]] = alloca | |||
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The breadcrumbs for this codegen test points back at #111634 which had to do with internal refactorings about how methods were done. I don't believe that these codegen tests are really all that applicable any more so I did my best to at least keep them somewhat, but the extra #[inline] in this PR effectively means that the internals this test relies on also changed which means that the test needed an update one way or another.
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This commit simplifies the internal implementation of
Defaultfor these two pointer types to have the same performance characteristics as before (a side effect of changes in #131460) while avoid use of internal private APIs of Rc/Arc. To preserve the same codegen as before some non-generic functions needed to be tagged as#[inline]as well, but otherwise the same IR is produced before/after this change.The motivation of this commit is I was studying up on the state of initialization of
ArcandRcand figured it'd be nicer to reduce the use of internal APIs and instead use public stable APIs where possible, even in the implementation itself.