On Mon, 26 Jun 2023, juzhe.zh...@rivai.ai wrote:
> Hi, Richi.
>
> >> I think you can use ordered_min here? Alternatively doing ...
>
> I check the function of ordered_min:
> ordered_min (const poly_int_pod<N, Ca> &a, const poly_int_pod<N, Cb> &b)
> {
> if (known_le (a, b))
> return a;
> else
> {
> if (N > 1)
> gcc_checking_assert (known_le (b, a));
> return b;
> }
> }
>
> It seems that assertion will fail When nunits = [2,2] , len + bias = 3, for
> example.
Yes, looks like so.
> I may be wrong.
I guess it would be nice to re-formulate the loop in terms of
the encoded VECTOR_CST elts, but then we need to generate
the "extents" for set bits, not sure how to do that here.
Note in the end we get HOST_WIDE_INT extents from adding
the element size for each mask element we look at. The question
is how and if we currently handle the trailing ... correctly
for VL vectors.
It should be a matter of creating a few testcases where we
expect (or expect not) to CSE a [masked] VL vector load with
one or multiple stores. Like if we have
*v = 0;
*(v + vls) = 1;
... = *(v + vls/2);
that is, two VL vector stores that are "adjacent" and one
load that half-overlaps both. That 'vls' would be a
poly-int CST then. It might be possible to create the
above with intrinsics(?), for sure within a loop by
vectorization.
Richard.
> Thanks.
>
>
> juzhe.zh...@rivai.ai
>
> From: Richard Biener
> Date: 2023-06-26 20:16
> To: Ju-Zhe Zhong
> CC: gcc-patches; richard.sandiford
> Subject: Re: [PATCH V3] SCCVN: Add LEN_MASK_STORE and fix LEN_STORE
> On Mon, 26 Jun 2023, juzhe.zh...@rivai.ai wrote:
>
> > From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
> >
> > Hi, Richi. It seems that we use nunits which is len + bias to iterate then
> > we can
> > simplify the codes.
> >
> > Also, I fixed behavior of len_store,
> >
> > Before this patch:
> > (len - bias) * BITS_PER_UNIT
> > After this patch:
> > (len + bias) * BITS_PER_UNIT
> >
> > gcc/ChangeLog:
> >
> > * tree-ssa-sccvn.cc (vn_reference_lookup_3): Add LEN_MASK_STORE and
> > fix LEN_STORE.
> >
> > ---
> > gcc/tree-ssa-sccvn.cc | 24 ++++++++++++++++++++++--
> > 1 file changed, 22 insertions(+), 2 deletions(-)
> >
> > diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
> > index 11061a374a2..d66e75460ed 100644
> > --- a/gcc/tree-ssa-sccvn.cc
> > +++ b/gcc/tree-ssa-sccvn.cc
> > @@ -3304,6 +3304,16 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void
> > *data_,
> > if (!tree_fits_uhwi_p (len) || !tree_fits_shwi_p (bias))
> > return (void *)-1;
> > break;
> > + case IFN_LEN_MASK_STORE:
> > + len = gimple_call_arg (call, 2);
> > + bias = gimple_call_arg (call, 5);
> > + if (!tree_fits_uhwi_p (len) || !tree_fits_shwi_p (bias))
> > + return (void *)-1;
> > + mask = gimple_call_arg (call, internal_fn_mask_index (fn));
> > + mask = vn_valueize (mask);
> > + if (TREE_CODE (mask) != VECTOR_CST)
> > + return (void *)-1;
> > + break;
> > default:
> > return (void *)-1;
> > }
> > @@ -3344,6 +3354,16 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void
> > *data_,
> > tree vectype = TREE_TYPE (def_rhs);
> > unsigned HOST_WIDE_INT elsz
> > = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (vectype)));
> > + poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vectype);
> > + if (len)
> > + {
> > + /* Since the following while condition known_lt
> > + (mask_idx, nunits) will exit the while loop
> > + when mask_idx > nunits.coeffs[0], we pick the
> > + MIN (nunits.coeffs[0], len + bias). */
> > + nunits = MIN (nunits.coeffs[0],
> > + tree_to_uhwi (len) + tree_to_shwi (bias));
>
> I think you can use ordered_min here? Alternatively doing ...
>
> > + }
> > if (mask)
> > {
> > HOST_WIDE_INT start = 0, length = 0;
> > @@ -3373,7 +3393,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void
> > *data_,
> > length += elsz;
> > mask_idx++;
> > }
> > - while (known_lt (mask_idx, TYPE_VECTOR_SUBPARTS (vectype)));
> > + while (known_lt (mask_idx, nunits));
>
> && mask_id < len
>
> would be possible.
>
> Richard?
>
> Thanks,
> Richard.
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
