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

[Peter Maydell]

On Fri, 14 May 2021 at 17:33, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> 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.

Seems reasonable, but can you put that in a separate patch if you want
to do it, please?

thanks
-- PMM