> -----Original Message-----
> From: Richard Biener <rguent...@suse.de>
> Sent: Thursday, July 31, 2025 12:27 PM
> To: gcc-patches@gcc.gnu.org
> Cc: Tamar Christina <tamar.christ...@arm.com>
> Subject: [PATCH] Add checks for node in aarch64 vector cost modeling
>
> After removing STMT_VINFO_MEMORY_ACCESS_TYPE we now ICE when costing
> for scalar stmts required in the epilog since the cost model tries
> to pattern-match gathers (an earlier patch tried to improve this
> by introducing stmt groups, but that was on hold due to negative
> feedback). The following shot-cuts those attempts when node is NULL
> as that then cannot be a vector stmt. Another possibility would be
> to gate on vect_body, or restructure everything.
>
> Note we now ensure that when m_costing_for_scalar node is NULL.
>
> Tested with check-gcc vect.exp with a cross. OK?
OK.
Thanks,
Tamar
>
> Thanks,
> Richard.
>
> * config/aarch64/aarch64.cc (aarch64_detect_vector_stmt_subtype):
> Check for node before dereferencing.
> (aarch64_vector_costs::add_stmt_cost): Likewise.
> ---
> gcc/config/aarch64/aarch64.cc | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index a761addc06c..ed37824b6a2 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -17465,6 +17465,7 @@ aarch64_detect_vector_stmt_subtype (vec_info
> *vinfo, vect_cost_for_stmt kind,
> for each element. We therefore need to divide the full-instruction
> cost by the number of elements in the vector. */
> if (kind == scalar_load
> + && node
> && sve_costs
> && SLP_TREE_MEMORY_ACCESS_TYPE (node) == VMAT_GATHER_SCATTER)
> {
> @@ -17478,6 +17479,7 @@ aarch64_detect_vector_stmt_subtype (vec_info
> *vinfo, vect_cost_for_stmt kind,
> /* Detect cases in which a scalar_store is really storing one element
> in a scatter operation. */
> if (kind == scalar_store
> + && node
> && sve_costs
> && SLP_TREE_MEMORY_ACCESS_TYPE (node) == VMAT_GATHER_SCATTER)
> return sve_costs->scatter_store_elt_cost;
> @@ -18005,7 +18007,7 @@ aarch64_vector_costs::add_stmt_cost (int count,
> vect_cost_for_stmt kind,
>
> /* Check if we've seen an SVE gather/scatter operation and which size.
> */
> if (kind == scalar_load
> - && !m_costing_for_scalar
> + && node
> && vectype
> && aarch64_sve_mode_p (TYPE_MODE (vectype))
> && SLP_TREE_MEMORY_ACCESS_TYPE (node) ==
> VMAT_GATHER_SCATTER)
> --
> 2.43.0
