https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119103
--- Comment #16 from Niklas Haas <gcc at haasn dot dev> ---
(In reply to Alexander Monakov from comment #15)
> (In reply to Niklas Haas from comment #12)
> > Out of curiosity, is there a work-around that I could use to get current
> > versions of GCC to compile the right thing, but without breaking
> > cross-platform compatibility?
> >
> > I did try replacing the assertion by "x[i] << (amount & 0xF)" but the vector
> > version of the code at least still compiles down to vpslld.
>
> This quote seems apropos: "autovectorization is not a programming model".
This is true, but if I need to write portable C code I have no choice but to
rely on auto-vectorization, unless I want to pepper my code with `#ifdef
__GNUC__` and provide multiple implementations for everything.
>
> Not sure if you know that already, but with generic vectors you can write:
>
> typedef uint16_t u16v16 __attribute__((vector_size(32)));
> typedef u16v16 u16v16_u __attribute__((aligned(2)));
>
> void lshift_register(u16v16_u *x, uint8_t amount)
> {
> *x <<= amount;
> }
Thanks, I'll use that as a GCC-specific work-around for now in this particular
case.
