On Sat, Aug 02, 2025 at 05:14:24PM +0800, Yang Yujie wrote:
> A _BitInt value may rely on a conversion to become properly extended.
> So a conversion to _BitInt is not trivially removable even if the
> types of the result and the operand have the same precision and size.
>
> This patches fixes gcc.dg/torture/bitint-64.c at -O2 on LoongArch,
> which fails because extension of the result is dropped in a
> compare-and-swap loop generated for incrementing an _Atomic _BitInt,
> causing an ABI violation.
>
> gcc/ChangeLog:
>
> * match.pd: Preserve conversion to _BitInt before a VCE
> if the _BitInt is extended.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/torture/bitint-84.c: New test.
LGTM.
Jakub
