Thanks Richi,
Address comment on V3:
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/625167.html
Bootstrap and regression is on the way.
juzhe.zh...@rivai.ai
From: Richard Biener
Date: 2023-07-21 18:51
To: Ju-Zhe Zhong
CC: gcc-patches; richard.sandiford
Subject: Re: [PATCH V2] VECT: Support floating-point in-order reduction for
length loop control
On Fri, 21 Jul 2023, juzhe.zh...@rivai.ai wrote:
> From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
>
> Hi, Richard and Richi.
>
> This patch support floating-point in-order reduction for loop length control.
>
> Consider this following case:
>
> float foo (float *__restrict a, int n)
> {
> float result = 1.0;
> for (int i = 0; i < n; i++)
> result += a[i];
> return result;
> }
>
> When compile with **NO** -ffast-math on ARM SVE, we will end up with:
>
> loop_mask = WHILE_ULT
> result = MASK_FOLD_LEFT_PLUS (...loop_mask...)
>
> For RVV, we don't use length loop control instead of mask:
>
> So, with this patch, we expect to see:
>
> loop_len = SELECT_VL
> result = MASK_LEN_FOLD_LEFT_PLUS (...loop_len...)
>
> gcc/ChangeLog:
>
> * tree-vect-loop.cc (get_masked_reduction_fn): Add mask_len_fold_left.
> (vectorize_fold_left_reduction): Ditto.
> (vectorizable_reduction): Ditto.
> (vect_transform_reduction): Ditto.
>
> ---
> gcc/tree-vect-loop.cc | 41 ++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index b44fb9c7712..59ab7879d55 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -6800,11 +6800,13 @@ static internal_fn
> get_masked_reduction_fn (internal_fn reduc_fn, tree vectype_in)
> {
> internal_fn mask_reduc_fn;
> + internal_fn mask_len_reduc_fn;
>
> switch (reduc_fn)
> {
> case IFN_FOLD_LEFT_PLUS:
> mask_reduc_fn = IFN_MASK_FOLD_LEFT_PLUS;
> + mask_len_reduc_fn = IFN_MASK_LEN_FOLD_LEFT_PLUS;
> break;
>
> default:
> @@ -6814,6 +6816,9 @@ get_masked_reduction_fn (internal_fn reduc_fn, tree
> vectype_in)
> if (direct_internal_fn_supported_p (mask_reduc_fn, vectype_in,
> OPTIMIZE_FOR_SPEED))
> return mask_reduc_fn;
> + if (direct_internal_fn_supported_p (mask_len_reduc_fn, vectype_in,
> + OPTIMIZE_FOR_SPEED))
> + return mask_len_reduc_fn;
> return IFN_LAST;
> }
>
> @@ -6834,7 +6839,8 @@ vectorize_fold_left_reduction (loop_vec_info loop_vinfo,
> gimple *reduc_def_stmt,
> tree_code code, internal_fn reduc_fn,
> tree ops[3], tree vectype_in,
> - int reduc_index, vec_loop_masks *masks)
> + int reduc_index, vec_loop_masks *masks,
> + vec_loop_lens *lens)
> {
> class loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
> tree vectype_out = STMT_VINFO_VECTYPE (stmt_info);
> @@ -6896,8 +6902,18 @@ vectorize_fold_left_reduction (loop_vec_info
> loop_vinfo,
> {
> gimple *new_stmt;
> tree mask = NULL_TREE;
> + tree len = NULL_TREE;
> + tree bias = NULL_TREE;
> if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo))
> mask = vect_get_loop_mask (loop_vinfo, gsi, masks, vec_num, vectype_in, i);
> + if (LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo))
> + {
> + len = vect_get_loop_len (loop_vinfo, gsi, lens, vec_num, vectype_in,
> + i, 1);
> + signed char biasval = LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo);
> + bias = build_int_cst (intQI_type_node, biasval);
> + mask = build_minus_one_cst (truth_type_for (vectype_in));
> + }
>
> /* Handle MINUS by adding the negative. */
> if (reduc_fn != IFN_LAST && code == MINUS_EXPR)
> @@ -6917,7 +6933,10 @@ vectorize_fold_left_reduction (loop_vec_info
> loop_vinfo,
> the preceding operation. */
> if (reduc_fn != IFN_LAST || (mask && mask_reduc_fn != IFN_LAST))
> {
> - if (mask && mask_reduc_fn != IFN_LAST)
> + if (len && mask && mask_reduc_fn != IFN_LAST)
check mask_reduc_fn == IFN_MASK_LEN_FOLD_LEFT_PLUS instead?
> + new_stmt = gimple_build_call_internal (mask_reduc_fn, 5, reduc_var,
> + def0, mask, len, bias);
> + else if (mask && mask_reduc_fn != IFN_LAST)
Likewise.
Otherwise looks good to me.
Richard.
> new_stmt = gimple_build_call_internal (mask_reduc_fn, 3, reduc_var,
> def0, mask);
> else
> @@ -7979,6 +7998,7 @@ vectorizable_reduction (loop_vec_info loop_vinfo,
> else if (loop_vinfo && LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo))
> {
> vec_loop_masks *masks = &LOOP_VINFO_MASKS (loop_vinfo);
> + vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
> internal_fn cond_fn = get_conditional_internal_fn (op.code, op.type);
>
> if (reduction_type != FOLD_LEFT_REDUCTION
> @@ -8006,8 +8026,17 @@ vectorizable_reduction (loop_vec_info loop_vinfo,
> LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo) = false;
> }
> else
> - vect_record_loop_mask (loop_vinfo, masks, ncopies * vec_num,
> - vectype_in, NULL);
> + {
> + internal_fn mask_reduc_fn
> + = get_masked_reduction_fn (reduc_fn, vectype_in);
> +
> + if (mask_reduc_fn == IFN_MASK_LEN_FOLD_LEFT_PLUS)
> + vect_record_loop_len (loop_vinfo, lens, ncopies * vec_num,
> + vectype_in, 1);
> + else
> + vect_record_loop_mask (loop_vinfo, masks, ncopies * vec_num,
> + vectype_in, NULL);
> + }
> }
> return true;
> }
> @@ -8137,6 +8166,7 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
> code_helper code = canonicalize_code (op.code, op.type);
> internal_fn cond_fn = get_conditional_internal_fn (code, op.type);
> vec_loop_masks *masks = &LOOP_VINFO_MASKS (loop_vinfo);
> + vec_loop_lens *lens = &LOOP_VINFO_LENS (loop_vinfo);
> bool mask_by_cond_expr = use_mask_by_cond_expr_p (code, cond_fn,
> vectype_in);
>
> /* Transform. */
> @@ -8162,7 +8192,8 @@ vect_transform_reduction (loop_vec_info loop_vinfo,
> gcc_assert (code.is_tree_code ());
> return vectorize_fold_left_reduction
> (loop_vinfo, stmt_info, gsi, vec_stmt, slp_node, reduc_def_phi,
> - tree_code (code), reduc_fn, op.ops, vectype_in, reduc_index, masks);
> + tree_code (code), reduc_fn, op.ops, vectype_in, reduc_index, masks,
> + lens);
> }
>
> bool single_defuse_cycle = STMT_VINFO_FORCE_SINGLE_CYCLE (reduc_info);
>
--
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)
