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.
--
2.36.3
