On Fri, May 20, 2016 at 5:24 PM, Richard Sandiford
<richard.sandif...@arm.com> wrote:
> vectorizable_load had a curious "force_peeling" variable, with no
> comment explaining why we need it for single-element interleaving
> but not for other cases. I think it's simply because we weren't
> initialising the GROUP_GAP correctly for single loads.
>
> Tested on aarch64-linux-gnu and x86_64-linux-gnu. OK to install?
Ok.
Thanks,
Richard.
> Thanks,
> Richard
>
>
> gcc/
> * tree-vect-data-refs.c (vect_analyze_group_access_1): Set
> GROUP_GAP for single-element interleaving.
> * tree-vect-stmts.c (vectorizable_load): Remove force_peeling
> variable.
>
> diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
> index 7652e21..36d302a 100644
> --- a/gcc/tree-vect-data-refs.c
> +++ b/gcc/tree-vect-data-refs.c
> @@ -2233,6 +2233,7 @@ vect_analyze_group_access_1 (struct data_reference *dr)
> {
> GROUP_FIRST_ELEMENT (vinfo_for_stmt (stmt)) = stmt;
> GROUP_SIZE (vinfo_for_stmt (stmt)) = groupsize;
> + GROUP_GAP (stmt_info) = groupsize - 1;
> if (dump_enabled_p ())
> {
> dump_printf_loc (MSG_NOTE, vect_location,
> diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
> index 9ab4af4..585c073 100644
> --- a/gcc/tree-vect-stmts.c
> +++ b/gcc/tree-vect-stmts.c
> @@ -6319,7 +6319,6 @@ vectorizable_load (gimple *stmt, gimple_stmt_iterator
> *gsi, gimple **vec_stmt,
> that leaves unused vector loads around punt - we at least create
> very sub-optimal code in that case (and blow up memory,
> see PR65518). */
> - bool force_peeling = false;
> if (first_stmt == stmt
> && !GROUP_NEXT_ELEMENT (stmt_info))
> {
> @@ -6333,7 +6332,7 @@ vectorizable_load (gimple *stmt, gimple_stmt_iterator
> *gsi, gimple **vec_stmt,
> }
>
> /* Single-element interleaving requires peeling for gaps. */
> - force_peeling = true;
> + gcc_assert (GROUP_GAP (stmt_info));
> }
>
> /* If there is a gap in the end of the group or the group size cannot
> @@ -6341,8 +6340,7 @@ vectorizable_load (gimple *stmt, gimple_stmt_iterator
> *gsi, gimple **vec_stmt,
> elements in the last iteration and thus need to peel that off. */
> if (loop_vinfo
> && ! STMT_VINFO_STRIDED_P (stmt_info)
> - && (force_peeling
> - || GROUP_GAP (vinfo_for_stmt (first_stmt)) != 0
> + && (GROUP_GAP (vinfo_for_stmt (first_stmt)) != 0
> || (!slp && vf % GROUP_SIZE (vinfo_for_stmt (first_stmt)) !=
> 0)))
> {
> if (dump_enabled_p ())
>
