Re: recent troubles with float vectors & bitwise ops

["Andrew Pinski" <pinskia at gmail dot com>]

On 8/22/07, Ross Ridge <rridge@csclub.uwaterloo.ca> wrote:
> GCC makes the problem is even worse if only SSE and not SSE 2 instructions
> are enabled.  Since the integer bitwise instructions are only available
> with SSE 2, using casts instead of intrinsics causes GCC to expand the
> operation into a long series of instructions.

And why do a bad decission based on another bad decission?  Why did
Intel split up these instructions in the first place, is it because
they wanted to have a seperate vector units in some cases?  I don't
know and I don't care that much.  This extension is supposed to be
generic and doing weird stuff by allowing bitwise operators on vector
float just confuses people more.  Yes Intel/AMD's specific instruction
set includes that but not everyone elses.

> If I were tbp, I'd just code all his vector operatations using intrinsics.
> The other responses in this thread have made it clear that GCC's vector
> arithemetic operations are really only designed to be used with the Cell
> Broadband Engine and other Power PC processors.

No, they were designed to be generic.  The issue comes down to what is
generic.  I am saying that don't allow it for scalar fp types, why
allow it for vector fp types?  The genericism here is that vector is
just an expansion on top of the scalar types.  Not many new features
are supposed to be added.

-- Pinski