https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88928
Bernd Edlinger <bernd.edlinger at hotmail dot de> changed:
What |Removed |Added
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CC| |bernd.edlinger at hotmail dot
de
--- Comment #2 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
(In reply to H.J. Lu from comment #1)
> We should warn:
>
> ---
> struct a { int i; } __attribute__((__packed__));
> void c (struct a **);
> void d (const struct a *b) { c ((struct a **) b); }
> --
>
> But should we warn
>
> --
> struct a { } __attribute__((__packed__));
> void c (struct a **);
> void d (const struct a *b) { c ((struct a **) b); }
> --
>
> in C? Since "struct a" is empty, can we ever generate unaligned access
> to an empty structure?
I think we should warn, because b is aligned(1)
and the code in question passes it to struct a **, which is aligned(8)
which can get an alignment trap.
