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-tree-vect-slp.c-vect_analyze_slp-When-reduction-grou.patch
0214d31a48f867b9b00134cea7223d35ed7865aa

diff --git a/gcc/testsuite/gcc.dg/vect/slp-reduc-9.c b/gcc/testsuite/gcc.dg/vect/slp-reduc-9.c
new file mode 100644
index 00000000000..bee642ee999
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/slp-reduc-9.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int_mult } */
+
+int
+bar (int *x, int a, int b, int n)
+{
+  x = __builtin_assume_aligned (x, __BIGGEST_ALIGNMENT__);
+  int sum1 = 0;
+  int sum2 = 0;
+  for (int i = 0; i < n; ++i)
+    {
+      /* Reduction chain vectorization fails here because of the
+         different operations but we can still vectorize both
+	 reductions as SLP reductions, saving IVs.  */
+      sum1 += x[2*i] - a;
+      sum1 += x[2*i+1] * b;
+      sum2 += x[2*i] - b;
+      sum2 += x[2*i+1] * a;
+    }
+  return sum1 + sum2;
+}
+
+/* { dg-final { scan-tree-dump "Loop contains only SLP stmts" "vect" } } */
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" } } */
+/* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" } } */
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index e1061ede061..0af51197a84 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -2271,14 +2271,18 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 	      {
 		/* Dissolve reduction chain group.  */
 		stmt_vec_info vinfo = first_element;
+		stmt_vec_info last = NULL;
 		while (vinfo)
 		  {
 		    stmt_vec_info next = REDUC_GROUP_NEXT_ELEMENT (vinfo);
 		    REDUC_GROUP_FIRST_ELEMENT (vinfo) = NULL;
 		    REDUC_GROUP_NEXT_ELEMENT (vinfo) = NULL;
+		    last = vinfo;
 		    vinfo = next;
 		  }
 		STMT_VINFO_DEF_TYPE (first_element) = vect_internal_def;
+		/* It can be still vectorized as part of an SLP reduction.  */
+		loop_vinfo->reductions.safe_push (last);
 	      }
 	}