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-Fix-reduc_index-calculation-in-vectorizable_conditio.patch
1d149b7260bcc4c0c6367b3aea47a8b91a1cf345

diff -Nurp a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
--- a/gcc/tree-vect-stmts.c	2020-08-18 19:35:06.352000000 +0800
+++ b/gcc/tree-vect-stmts.c	2020-08-18 19:35:20.792000000 +0800
@@ -9077,7 +9077,7 @@ vectorizable_condition (stmt_vec_info st
 	return false;
       reduc_info = info_for_reduction (stmt_info);
       reduction_type = STMT_VINFO_REDUC_TYPE (reduc_info);
-      reduc_index = STMT_VINFO_REDUC_IDX (reduc_info);
+      reduc_index = STMT_VINFO_REDUC_IDX (stmt_info);
       gcc_assert (reduction_type != EXTRACT_LAST_REDUCTION
 		  || reduc_index != -1);
     }