> -----Original Message-----
> From: Hongtao Liu <crazy...@gmail.com>
> Sent: Friday, May 17, 2024 3:14 AM
> To: Victor Do Nascimento <victor.donascime...@arm.com>
> Cc: gcc-patches@gcc.gnu.org; Richard Sandiford <richard.sandif...@arm.com>;
> Richard Earnshaw <richard.earns...@arm.com>; Victor Do Nascimento
> <vicdo...@e133397.arm.com>
> Subject: Re: [PATCH] middle-end: Expand {u|s}dot product support in
> autovectorizer
>
> > >
> > Sorry to chime in, for x86 backend, we defined usdot_prodv16hi, and
> > 2-way dot_prod operations can be generated
> >
> This is the link https://godbolt.org/z/hcWr64vx3, x86 define
> udot_prodv16qi/udot_prod8hi and both 2-way and 4-way dot_prod
> instructions are generated
>
That's not the same, the 2-way vs 4-way dot_prod here is that
e.g. udot_prod8hi can reduce to either DImode or SImode.
udot_prod8hi does not have enough information to distinguish the two and in RTL
you can't overload the names. So this is about the ISA having instructions
that overlap
on the source mode of the instruction.
Tamar
>
> --
> BR,
> Hongtao
