[Bug target/122018] x86 doesn't use BTS bitmanip instruction to both set and test bit

jakub at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Sun Aug 2 17:46:30 GMT 2026


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122018

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That doesn't make any sense.  (clobber:CCC flags) doesn't mean only the carry
bit in flags is clobbered and all others stay unmodified, it means exactly the
same as (clobber:CC flags), i.e. all flag bits contain unspecified values.
CCCmode is used for pairs of instructions to make it clear that only the carry
flag is meaningful and others are unspecified.


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