[Bug c/79217] Feature request: high half of an integer multiplication

[Bug c/79217] Feature request: high half of an integer multiplication

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79217

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to H. Peter Anvin from comment #5)
> b) it seems likely that getting __intN where N > CHAR_BIT*sizeof(uintmax_t)
> into a standard would be very hard, and thus would not be possible to
> standard-track (although it could be used as an implementation on gcc using
> a header inline, of course.)

I saw a proposal for C23 (I think it was C23) for arbitrary bit size integers. 
I don't know if that included big integers either.

[Bug c/79217] Feature request: high half of an integer multiplication

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79217

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #6)
> I saw a proposal for C23 (I think it was C23) for arbitrary bit size
> integers.  I don't know if that included big integers either.

It does and _BitInt(128) is supported on x86 (both 32 and 64 bit) in GCC 14.
aarch64 (Little-endian only) is adding support too and should be included in
GCC 14.

I think arm will be adding it for GCC 15 though.

I am not 100% sure but I suspect _BitInt support satisfies this request here.