re PR tree-optimization/83086 (valgrind error in gimple-ssa-store-merging.c for recent build)

	PR tree-optimization/83086
	* gimple-ssa-store-merging.c
	(imm_store_chain_info::try_coalesce_bswap): Test this_n.base_addr
	rather than n.base_addr.

From-SVN: r255002

gcc/ChangeLog

+2017-11-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/83086
+	* gimple-ssa-store-merging.c
+	(imm_store_chain_info::try_coalesce_bswap): Test this_n.base_addr
+	rather than n.base_addr.
+
 2017-11-21  Martin Liska  <mliska@suse.cz>
 
 	PR rtl-optimization/82044

gcc/gimple-ssa-store-merging.c

@@ -2390,7 +2390,7 @@ imm_store_chain_info::try_coalesce_bswap (merged_store_group *merged_store,
 			    ? try_size - info->bitsize - bitpos
 			    : bitpos))
 	return false;
-      if (n.base_addr && vuse_store)
+      if (this_n.base_addr && vuse_store)
 	{
 	  unsigned int j;
 	  for (j = first; j <= last; ++j)