procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

VECT: Change flow of decrement IV

Browse source 
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  <linkw@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.
This commit is contained in:
Ju-Zhe Zhong 2023-06-01 12:36:17 +08:00 • committed by Pan Li
parent 7bf89a919f
commit bffc52838e
1 changed files with 25 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
gcc/tree-vect-loop-manip.cc
View file

@ -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.