> -----Original Message-----
> From: Richard Biener <[email protected]>
> Sent: Wednesday, June 17, 2026 8:30 PM
> To: [email protected]
> Cc: Liu, Hongtao <[email protected]>
> Subject: [PATCH 4/5] [x86] Handle vec_deconstruct where appropriate
>
> The following replaces vec_to_scalar handling where now vec_deconstruct is
> expected.
Ok.
>
> * config/i386/i386.cc (ix86_default_vector_cost): Handle
> vec_deconstruct like vec_construct.
> (ix86_vector_costs::add_stmt_cost): Expect vec_deconstruct
> where formerly handling vec_to_scalar for emulated
> gather/scatter, elementwise and strided accesses.
> ---
> gcc/config/i386/i386.cc | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index
> bd0ecfddbbc..c0a0204b9b6 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -25724,6 +25724,7 @@ ix86_default_vector_cost (enum
> vect_cost_for_stmt type_of_cost,
> return ix86_vec_cost (mode, ix86_cost->sse_op);
>
> case vec_construct:
> + case vec_deconstruct:
> return ix86_vector_cd_cost (mode, GET_MODE_INNER (mode));
>
> default:
> @@ -26727,7 +26728,7 @@ ix86_vector_costs::add_stmt_cost (int count,
> vect_cost_for_stmt kind,
> latency and execution resources for the many scalar loads
> (AGU and load ports). Try to account for this by scaling the
> construction cost by the number of elements involved. */
> - if ((kind == vec_construct || kind == vec_to_scalar)
> + if ((kind == vec_construct || kind == vec_deconstruct)
> && ((node
> && (((SLP_TREE_MEMORY_ACCESS_TYPE (node) ==
> VMAT_ELEMENTWISE
> || (SLP_TREE_MEMORY_ACCESS_TYPE (node) ==
> VMAT_STRIDED_SLP
> --
> 2.51.0
