mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-03-02 00:46:20 +08:00
Code Issues Packages Projects Releases Wiki Activity

tree-optimization/97838 - fix SLP leaf detection

Browse Source 
This properly handles reduction PHI nodes with unrepresented
initial value as leaf in the SLP graph.

2020-11-16  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/97838
	* tree-vect-slp.c (vect_slp_build_vertices): Properly handle
	not backwards reachable cycles.
	(vect_optimize_slp): Check a node is leaf before marking it
	visited.

	* gcc.dg/vect/pr97838.c: New testcase.
This commit is contained in:
Richard Biener 2020-11-16 09:28:03 +01:00
parent 5e303cdee1
commit d0a206abc6
2 changed files with 28 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
gcc/testsuite/gcc.dg/vect/pr97838.c Normal file
View File

@ -0,0 +1,11 @@
/* { dg-do compile } */
int a, b, c, d;
void f() {
while (c++) {
int e = -1;
d = a ? e / a : e;
b ^= ~d;
}
}

22
gcc/tree-vect-slp.c
View File

@ -2629,8 +2629,18 @@ vect_slp_build_vertices (vec_info *info, vec<slp_tree> &vertices,
unsigned i;
slp_instance instance;
FOR_EACH_VEC_ELT (info->slp_instances, i, instance)
vect_slp_build_vertices (visited, SLP_INSTANCE_TREE (instance), vertices,
leafs);
{
unsigned n_v = vertices.length ();
unsigned n_l = leafs.length ();
vect_slp_build_vertices (visited, SLP_INSTANCE_TREE (instance), vertices,
leafs);
/* If we added vertices but no entries to the reverse graph we've
added a cycle that is not backwards-reachable. Push the entry
to mimic as leaf then. */
if (vertices.length () > n_v
&& leafs.length () == n_l)
leafs.safe_push (SLP_INSTANCE_TREE (instance)->vertex);
}
}
/* Apply (reverse) bijectite PERM to VEC. */
@ -2724,9 +2734,11 @@ vect_optimize_slp (vec_info *vinfo)
|| SLP_TREE_DEF_TYPE (node) == vect_constant_def)
continue;
/* Loads are the only thing generating permutes and leafs do not
change across iterations. */
bitmap_set_bit (n_visited, idx);
/* Leafs do not change across iterations. Note leafs also double
as entries to the reverse graph. */
if (!slpg->vertices[idx].succ)
bitmap_set_bit (n_visited, idx);
/* Loads are the only thing generating permutes. */
if (!SLP_TREE_LOAD_PERMUTATION (node).exists ())
continue;