mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-21 14:41:07 +08:00
Code Issues Packages Projects Releases Wiki Activity

Change the way we split stores in BB vectorization

Browse Source 
The following fixes missed optimizations due to the strange way we
split stores in BB vectorization.  The solution is to split at
the failure boundary and not re-align that to the initial piece
chosen vector size.  Also re-analyze any larger matching rest.

2020-10-28  Richard Biener  <rguenther@suse.de>

	* tree-vect-slp.c (vect_build_slp_instance): Split the store
	group at the failure boundary and also re-analyze a large enough
	matching rest.

	* gcc.dg/vect/bb-slp-68.c: New testcase.
This commit is contained in:
Richard Biener 2020-10-28 12:56:16 +01:00
parent ac1724ccfd
commit 2acb33103c
2 changed files with 35 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
gcc/testsuite/gcc.dg/vect/bb-slp-68.c Normal file
View File

@ -0,0 +1,22 @@
/* { dg-do compile } */
/* { dg-require-effective-target vect_double } */
/* { dg-additional-options "-mavx" { target avx } } */
double x[10], y[6], z[4];
void foo ()
{
x[0] = y[0];
x[1] = y[1];
x[2] = y[2];
x[3] = y[3];
x[4] = y[4];
x[5] = y[5];
x[6] = z[0] + 1.;
x[7] = z[1] + 1.;
x[8] = z[2] + 1.;
x[9] = z[3] + 1.;
}
/* We want to have the store group split into 4, 2, 4 when using 32byte vectors. */
/* { dg-final { scan-tree-dump-not "from scalars" "slp2" } } */

20
gcc/tree-vect-slp.c
View File

@ -2412,15 +2412,21 @@ vect_build_slp_instance (vec_info *vinfo,
group1_size);
bool res = vect_analyze_slp_instance (vinfo, bst_map, stmt_info,
max_tree_size);
/* If the first non-match was in the middle of a vector,
skip the rest of that vector. Do not bother to re-analyze
single stmt groups. */
if (group1_size < i)
/* Split the rest at the failure point and possibly
re-analyze the remaining matching part if it has
at least two lanes. */
if (group1_size < i
&& (i + 1 < group_size
|| i - group1_size > 1))
{
i = group1_size + const_nunits;
if (i + 1 < group_size)
rest = vect_split_slp_store_group (rest, const_nunits);
stmt_vec_info rest2 = rest;
rest = vect_split_slp_store_group (rest, i - group1_size);
if (i - group1_size > 1)
res |= vect_analyze_slp_instance (vinfo, bst_map,
rest2, max_tree_size);
}
/* Re-analyze the non-matching tail if it has at least
two lanes. */
if (i + 1 < group_size)
res |= vect_analyze_slp_instance (vinfo, bst_map,
rest, max_tree_size);