This backport contains 1 patch from gcc main stream tree.
The commit id of these patchs list as following in the order of time.

0001-re-PR-tree-optimization-92555-ICE-in-exact_div-at-po.patch
f1e0c7e0eb3eafb122fc3d00242828c82a9286a2

diff -Nurp a/gcc/testsuite/gcc.dg/vect/pr92555.c b/gcc/testsuite/gcc.dg/vect/pr92555.c
--- a/gcc/testsuite/gcc.dg/vect/pr92555.c	1970-01-01 08:00:00.000000000 +0800
+++ b/gcc/testsuite/gcc.dg/vect/pr92555.c	2020-08-11 09:36:18.060000000 +0800
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fwrapv" } */
+
+signed char rq;
+
+signed char
+pu (int tr, int al)
+{
+  signed char x8;
+
+  while (tr != 0)
+    {
+      for (x8 = 0; x8 >= 0; x8 += 2)
+        ;
+
+      rq ^= al ^ 1;
+      ++x8;
+      ++tr;
+    }
+
+  return x8;
+}
diff -Nurp a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
--- a/gcc/tree-vect-loop.c	2020-08-11 09:35:10.952000000 +0800
+++ b/gcc/tree-vect-loop.c	2020-08-11 09:36:18.064000000 +0800
@@ -1415,6 +1415,18 @@ vect_update_vf_for_slp (loop_vec_info lo
   for (i = 0; i < nbbs; i++)
     {
       basic_block bb = bbs[i];
+      for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si);
+	   gsi_next (&si))
+	{
+	  stmt_vec_info stmt_info = loop_vinfo->lookup_stmt (si.phi ());
+	  if (!stmt_info)
+	    continue;
+	  if ((STMT_VINFO_RELEVANT_P (stmt_info)
+	       || VECTORIZABLE_CYCLE_DEF (STMT_VINFO_DEF_TYPE (stmt_info)))
+	      && !PURE_SLP_STMT (stmt_info))
+	    /* STMT needs both SLP and loop-based vectorization.  */
+	    only_slp_in_loop = false;
+	}
       for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si);
 	   gsi_next (&si))
 	{