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.
I may be wrong.

Thanks.


juzhe.zhong@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.zhong@rivai.ai wrote:
 
> From: Ju-Zhe Zhong <juzhe.zhong@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.