This backport contains 2 patch from gcc main stream tree.
The commit id of these patchs list as following in the order of time.

0001-Fix-EXTRACT_LAST_REDUCTION-handling-of-pattern-stmts.patch
9ec35478ccf0f3539988a054b7996278706a7710

0001-Fix-EXTRACT_LAST_REDUCTION-segfault.patch
dc176c3ccd6a8cd3f809f3c1549ad00674061eb5

diff -Nurp a/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-6.c b/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-6.c
--- a/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-6.c	1969-12-31 19:00:00.000000000 -0500
+++ b/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-6.c	2020-12-14 21:16:26.492000000 -0500
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+
+int
+f (int *y)
+{
+  int res = 0;
+  for (int i = 0; i < 100; ++i)
+    res = (y[i] & 1) == 0 && (y[i] < 10) ? res : 1;
+  return res;
+}
diff -Nurp a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
--- a/gcc/tree-vect-stmts.c	2020-12-14 21:15:27.004000000 -0500
+++ b/gcc/tree-vect-stmts.c	2020-12-14 21:16:26.492000000 -0500
@@ -1777,9 +1777,10 @@ vect_finish_stmt_generation_1 (stmt_vec_
 stmt_vec_info
 vect_finish_replace_stmt (stmt_vec_info stmt_info, gimple *vec_stmt)
 {
-  gcc_assert (gimple_get_lhs (stmt_info->stmt) == gimple_get_lhs (vec_stmt));
+  gimple *scalar_stmt = vect_orig_stmt (stmt_info)->stmt;
+  gcc_assert (gimple_get_lhs (scalar_stmt) == gimple_get_lhs (vec_stmt));
 
-  gimple_stmt_iterator gsi = gsi_for_stmt (stmt_info->stmt);
+  gimple_stmt_iterator gsi = gsi_for_stmt (scalar_stmt);
   gsi_replace (&gsi, vec_stmt, true);
 
   return vect_finish_stmt_generation_1 (stmt_info, vec_stmt);
@@ -9118,10 +9119,12 @@ vectorizable_condition (stmt_vec_info st
 	  if (new_code == ERROR_MARK)
 	    must_invert_cmp_result = true;
 	  else
-	    cond_code = new_code;
+	    {
+	      cond_code = new_code;
+	      /* Make sure we don't accidentally use the old condition.  */
+	      cond_expr = NULL_TREE;
+	    }
 	}
-      /* Make sure we don't accidentally use the old condition.  */
-      cond_expr = NULL_TREE;
       std::swap (then_clause, else_clause);
     }
 
@@ -9426,20 +9429,21 @@ vectorizable_condition (stmt_vec_info st
 		  vect_finish_stmt_generation (stmt_info, new_stmt, gsi);
 		  vec_compare = vec_compare_name;
 		}
+	      gimple *old_stmt = vect_orig_stmt (stmt_info)->stmt;
+	      tree lhs = gimple_get_lhs (old_stmt);
 	      gcall *new_stmt = gimple_build_call_internal
 		(IFN_FOLD_EXTRACT_LAST, 3, else_clause, vec_compare,
 		 vec_then_clause);
-	      gimple_call_set_lhs (new_stmt, scalar_dest);
-	      SSA_NAME_DEF_STMT (scalar_dest) = new_stmt;
-	      if (stmt_info->stmt == gsi_stmt (*gsi))
+	      gimple_call_set_lhs (new_stmt, lhs);
+	      SSA_NAME_DEF_STMT (lhs) = new_stmt;
+	      if (old_stmt == gsi_stmt (*gsi))
 		new_stmt_info = vect_finish_replace_stmt (stmt_info, new_stmt);
 	      else
 		{
 		  /* In this case we're moving the definition to later in the
 		     block.  That doesn't matter because the only uses of the
 		     lhs are in phi statements.  */
-		  gimple_stmt_iterator old_gsi
-		    = gsi_for_stmt (stmt_info->stmt);
+		  gimple_stmt_iterator old_gsi = gsi_for_stmt (old_stmt);
 		  gsi_remove (&old_gsi, true);
 		  new_stmt_info
 		    = vect_finish_stmt_generation (stmt_info, new_stmt, gsi);