vcompress packs vl or less fields into vd, so the tail starts after the
last packed field.

Signed-off-by: Anton Blanchard <antonb@tenstorrent.com>
---
 target/riscv/vector_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index 072bd444b1..ccb32e6122 100644
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -5132,7 +5132,7 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, void *vs2,               \
     }                                                                     \
     env->vstart = 0;                                                      \
     /* set tail elements to 1s */                                         \
-    vext_set_elems_1s(vd, vta, vl * esz, total_elems * esz);              \
+    vext_set_elems_1s(vd, vta, num * esz, total_elems * esz);             \
 }
 
 /* Compress into vd elements of vs2 where vs1 is enabled */
-- 
2.34.1

On Wed, Oct 30, 2024 at 11:13 AM Anton Blanchard <antonb@tenstorrent.com> wrote:
>
> vcompress packs vl or less fields into vd, so the tail starts after the
> last packed field.

Is that right?

It's different from every other vector command. Although the wording
in the spec is very confusing

Alistair

Hi Alistair,

On Wed, Oct 30, 2024 at 2:39 PM Alistair Francis <alistair23@gmail.com>
wrote:
> > vcompress packs vl or less fields into vd, so the tail starts after the
> > last packed field.
>
> Is that right?
>
> It's different from every other vector command. Although the wording
> in the spec is very confusing

It is confusing. This thread has some clarification, and we should probably
follow up on the suggestion to improve the ISA wording:

https://github.com/riscv/riscv-v-spec/issues/796

Thanks,
Anton

On Wed, Oct 30, 2024 at 2:09 PM Anton Blanchard <antonb@tenstorrent.com> wrote:
>
> Hi Alistair,
>
> On Wed, Oct 30, 2024 at 2:39 PM Alistair Francis <alistair23@gmail.com> wrote:
> > > vcompress packs vl or less fields into vd, so the tail starts after the
> > > last packed field.
> >
> > Is that right?
> >
> > It's different from every other vector command. Although the wording
> > in the spec is very confusing
>
> It is confusing. This thread has some clarification, and we should probably
> follow up on the suggestion to improve the ISA wording:
>
> https://github.com/riscv/riscv-v-spec/issues/796

Ah, at least it isn't just me.

It's worth pointing to that in the commit message, as the spec is not
clear about this

Alistair

>
> Thanks,
> Anton