[gcc r15-3794] tree-optimization/116810 - out-of-bound access to matches[]

[Richard Biener via Gcc-cvs]

https://gcc.gnu.org/g:2c04f175de4f3985d783511662375d52f2cf4ad8

commit r15-3794-g2c04f175de4f3985d783511662375d52f2cf4ad8
Author: Richard Biener <rguent...@suse.de>
Date:   Mon Sep 23 10:30:32 2024 +0200

    tree-optimization/116810 - out-of-bound access to matches[]
    
    The following makes sure to apply forced splitting of groups for
    firced single-lane SLP only when the group being analyzed has more
    than one lane.  This avoids an out-of-bound access to matches[].
    
            PR tree-optimization/116810
            * tree-vect-slp.cc (vect_build_slp_instance): Onlu force
            splitting for group_size > 1.

Diff:
---
 gcc/tree-vect-slp.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 7161492f5114..ab49bb0e7ee1 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -3715,7 +3715,7 @@ vect_build_slp_instance (vec_info *vinfo,
   unsigned i;
 
   slp_tree node = NULL;
-  if (force_single_lane)
+  if (group_size > 1 && force_single_lane)
     {
       matches[0] = true;
       matches[1] = false;