https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99919
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2021-11-30
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot
gnu.org
Target Milestone|9.5 |13.0
Keywords| |deferred
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Aldy Hernandez from comment #3)
> The warning on the above IL seems legit.
>
> x_5 is initialized from b$i_11 when b & 1 == 0, but the read from x_5
> happens when b & 2 != 0. So the set and the read are predicated on two
> different things.
>
> Maybe I'm missing some subtle bit field thing. Does setting b.j somehow
> alter b.i?
b.j is (b&2)<<1.
If lower bit field acceses it is fixed (but also becomes more obvious what the
of b.j is:
_20 = VIEW_CONVERT_EXPR<unsigned char>(b);
_21 = BIT_INSERT_EXPR <_20, b$j_15, 1 (1 bits)>;
VIEW_CONVERT_EXPR<unsigned char>(b) = _21;
_3 = VIEW_CONVERT_EXPR<unsigned char>(b);
_4 = _3 & 2;
So Mine for GCC 13.
