On Thu, 1 Jun 2023, juzhe.zh...@rivai.ai wrote:
> This patch is no difference from V2.
> Just add PR tree-optimization/109971 as Kewen's suggested.
>
> Already bootstrapped and Regression on X86 no difference.
>
> Ok for trunk ?
OK.
Richard.
>
> juzhe.zh...@rivai.ai
>
> From: juzhe.zhong
> Date: 2023-06-01 12:36
> To: gcc-patches
> CC: richard.sandiford; rguenther; linkw; Ju-Zhe Zhong
> Subject: [PATCH V3] VECT: Change flow of decrement IV
> From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
>
> Follow Richi's suggestion, I change current decrement IV flow from:
>
> do {
> remain -= MIN (vf, remain);
> } while (remain != 0);
>
> into:
>
> do {
> old_remain = remain;
> len = MIN (vf, remain);
> remain -= vf;
> } while (old_remain >= vf);
>
> to enhance SCEV.
>
> Include fixes from kewen.
>
>
> This patch will need to wait for Kewen's test feedback.
>
> Testing on X86 is on-going
>
> Co-Authored by: Kewen Lin <li...@linux.ibm.com>
>
> PR tree-optimization/109971
>
> gcc/ChangeLog:
>
> * tree-vect-loop-manip.cc (vect_set_loop_controls_directly): Change
> decrement IV flow.
> (vect_set_loop_condition_partial_vectors): Ditto.
>
> ---
> gcc/tree-vect-loop-manip.cc | 36 +++++++++++++++++++++++++-----------
> 1 file changed, 25 insertions(+), 11 deletions(-)
>
> diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
> index acf3642ceb2..3f735945e67 100644
> --- a/gcc/tree-vect-loop-manip.cc
> +++ b/gcc/tree-vect-loop-manip.cc
> @@ -483,7 +483,7 @@ vect_set_loop_controls_directly (class loop *loop,
> loop_vec_info loop_vinfo,
> gimple_stmt_iterator loop_cond_gsi,
> rgroup_controls *rgc, tree niters,
> tree niters_skip, bool might_wrap_p,
> - tree *iv_step)
> + tree *iv_step, tree *compare_step)
> {
> tree compare_type = LOOP_VINFO_RGROUP_COMPARE_TYPE (loop_vinfo);
> tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
> @@ -538,9 +538,9 @@ vect_set_loop_controls_directly (class loop *loop,
> loop_vec_info loop_vinfo,
> ...
> vect__4.8_28 = .LEN_LOAD (_17, 32B, _36, 0);
> ...
> - ivtmp_35 = ivtmp_9 - _36;
> + ivtmp_35 = ivtmp_9 - POLY_INT_CST [4, 4];
> ...
> - if (ivtmp_35 != 0)
> + if (ivtmp_9 > POLY_INT_CST [4, 4])
> goto <bb 4>; [83.33%]
> else
> goto <bb 5>; [16.67%]
> @@ -549,13 +549,15 @@ vect_set_loop_controls_directly (class loop *loop,
> loop_vec_info loop_vinfo,
> tree step = rgc->controls.length () == 1 ? rgc->controls[0]
> : make_ssa_name (iv_type);
> /* Create decrement IV. */
> - create_iv (nitems_total, MINUS_EXPR, step, NULL_TREE, loop, &incr_gsi,
> - insert_after, &index_before_incr, &index_after_incr);
> + create_iv (nitems_total, MINUS_EXPR, nitems_step, NULL_TREE, loop,
> + &incr_gsi, insert_after, &index_before_incr,
> + &index_after_incr);
> gimple_seq_add_stmt (header_seq, gimple_build_assign (step, MIN_EXPR,
> index_before_incr,
> nitems_step));
> *iv_step = step;
> - return index_after_incr;
> + *compare_step = nitems_step;
> + return index_before_incr;
> }
> /* Create increment IV. */
> @@ -825,6 +827,7 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
> arbitrarily pick the last. */
> tree test_ctrl = NULL_TREE;
> tree iv_step = NULL_TREE;
> + tree compare_step = NULL_TREE;
> rgroup_controls *rgc;
> rgroup_controls *iv_rgc = nullptr;
> unsigned int i;
> @@ -861,7 +864,7 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
> &preheader_seq, &header_seq,
> loop_cond_gsi, rgc, niters,
> niters_skip, might_wrap_p,
> - &iv_step);
> + &iv_step, &compare_step);
> iv_rgc = rgc;
> }
> @@ -884,10 +887,21 @@ vect_set_loop_condition_partial_vectors (class loop
> *loop,
> /* Get a boolean result that tells us whether to iterate. */
> edge exit_edge = single_exit (loop);
> - tree_code code = (exit_edge->flags & EDGE_TRUE_VALUE) ? EQ_EXPR : NE_EXPR;
> - tree zero_ctrl = build_zero_cst (TREE_TYPE (test_ctrl));
> - gcond *cond_stmt = gimple_build_cond (code, test_ctrl, zero_ctrl,
> - NULL_TREE, NULL_TREE);
> + gcond *cond_stmt;
> + if (LOOP_VINFO_USING_DECREMENTING_IV_P (loop_vinfo))
> + {
> + gcc_assert (compare_step);
> + tree_code code = (exit_edge->flags & EDGE_TRUE_VALUE) ? LE_EXPR :
> GT_EXPR;
> + cond_stmt = gimple_build_cond (code, test_ctrl, compare_step,
> NULL_TREE,
> + NULL_TREE);
> + }
> + else
> + {
> + tree_code code = (exit_edge->flags & EDGE_TRUE_VALUE) ? EQ_EXPR :
> NE_EXPR;
> + tree zero_ctrl = build_zero_cst (TREE_TYPE (test_ctrl));
> + cond_stmt
> + = gimple_build_cond (code, test_ctrl, zero_ctrl, NULL_TREE, NULL_TREE);
> + }
> gsi_insert_before (&loop_cond_gsi, cond_stmt, GSI_SAME_STMT);
> /* The loop iterates (NITERS - 1) / VF + 1 times.
>
--
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)
