https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108199
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2022-12-22
Summary|Bitfields and |Bitfields, unions and SRA
|storage_order_attribute |and storage_order_attribute
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andreas Krebbel from comment #2)
> The problem appears to get introduced when dead store elimination removes
> the assignment to the target struct in FRE.
There is no DSE in FRE going on .... Rather SRA did messed up.
>
> Before FRE we have the following:
>
> _1 = src_6(D)->a; bswap
> dst$val_9 = _1; bswap
> _2 = BIT_FIELD_REF <dst$val_9, 8, 0>; bswap
> _3 = _2 & 64;
> if (_3 != 0)
dst$val_9/_1 are both SSA names and not a store/load. so there is no swapping
going on.
It is definitely SRA going wrong.
Turning off SRA (-fno-sra) and we get the correct thing at the end.
