Re: [PATCH v6 48/82] target/arm: Pass separate addend to {U, S}DOT helpers

[Richard Henderson]

On 5/13/21 5:47 AM, Peter Maydell wrote:
> On Fri, 30 Apr 2021 at 21:57, Richard Henderson
> <richard.henderson@linaro.org> wrote:
> > For SVE, we potentially have a 4th argument coming from the
> > movprfx instruction.  Currently we do not optimize movprfx,
> > so the problem is not visible.
> >
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > ---
> > v4: Fix double addition (zhiwei).
> > ---
> >   target/arm/helper.h         |  20 +++---
> >   target/arm/sve.decode       |   7 ++-
> >   target/arm/translate-a64.c  |  15 ++++-
> >   target/arm/translate-neon.c |  10 +--
> >   target/arm/translate-sve.c  |  13 ++--
> >   target/arm/vec_helper.c     | 120 ++++++++++++++++++++----------------
> >   6 files changed, 109 insertions(+), 76 deletions(-)
>
> > diff --git a/target/arm/vec_helper.c b/target/arm/vec_helper.c
> > index a3d80ecad0..f88e572132 100644
> > --- a/target/arm/vec_helper.c
> > +++ b/target/arm/vec_helper.c
> > @@ -375,71 +375,76 @@ void HELPER(sve2_sqrdmlsh_d)(void *vd, void *vn, void *vm,
> >    * All elements are treated equally, no matter where they are.
> >    */
> >
> > -void HELPER(gvec_sdot_b)(void *vd, void *vn, void *vm, uint32_t desc)
> > +void HELPER(gvec_sdot_b)(void *vd, void *vn, void *vm, void *va, uint32_t desc)
> >   {
> >       intptr_t i, opr_sz = simd_oprsz(desc);
> > -    uint32_t *d = vd;
> > +    int32_t *d = vd, *a = va;
>
> Why the type change ?

Oh, just because this is logically producing a signed result.  Given that we 
use -fwrapv, there is no functional change.


r~