Commit 5e474f7

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allocate before calling T::default in <Arc<T>>::default()

Same rationale as in the previous commit.

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+10

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+10

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Lines changed: 1 addition & 0 deletions

Lines changed: 7 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -3447,7 +3447,13 @@ impl<T: Default> Default for Arc<T> {`
`3447`	`3447`	`/// assert_eq!(*x, 0);`
`3448`	`3448`	/// ```
`3449`	`3449`	`fn default() -> Arc<T> {`
`3450`		`- Arc::new(Default::default())`
	`3450`	`+ let x = Box::into_raw(Box::write(Box::new_uninit(), ArcInner {`
	`3451`	`+ strong: atomic::AtomicUsize::new(1),`
	`3452`	`+ weak: atomic::AtomicUsize::new(1),`
	`3453`	`+ data: T::default(),`
	`3454`	`+ }));`
	`3455`	+ // SAFETY: `Box::into_raw` consumes the `Box` and never returns null
	`3456`	`+ unsafe { Self::from_inner(NonNull::new_unchecked(x)) }`
`3451`	`3457`	`}`
`3452`	`3458`	`}`
`3453`	`3459`

Lines changed: 2 additions & 2 deletions

Original file line number	Diff line number	Diff line change
`@@ -19,9 +19,9 @@ pub fn box_default_inplace() -> Box<(String, String)> {`
`19`	`19`	`// CHECK-LABEL: @arc_default_inplace`
`20`	`20`	`#[no_mangle]`
`21`	`21`	`pub fn arc_default_inplace() -> Arc<(String, String)> {`
`22`		`- // CHECK: [[ALLOCA:%.*]] = alloca`
	`22`	`+ // CHECK-NOT: alloca`
`23`	`23`	`// CHECK: [[ARC:%.]] = {{.}}call {{.*}}__rust_alloc(`
`24`		`- // CHECK: call void @llvm.memcpy`
	`24`	`+ // CHECK-NOT: call void @llvm.memcpy`
`25`	`25`	`// CHECK: ret ptr [[ARC]]`
`26`	`26`	`Arc::default()`
`27`	`27`	`}`

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