Added compiler fence to block reordering

I'm reasonably certain that this is a compiler bug...

1 files changed, 6 insertions, 0 deletions

diff --git a/include/shard/ISAMTree.h b/include/shard/ISAMTree.h
index 33ba82f..9458b1f 100644
--- a/include/shard/ISAMTree.h
+++ b/include/shard/ISAMTree.h
@@ -65,6 +65,12 @@ public:
                                                  sizeof(Wrapped<R>), 
                                                (byte**) &m_data);
 
+        /* 
+         * without this, gcc seems to hoist the building of the array
+         * _above_ its allocation under -O3, resulting in memfaults.
+         */
+        asm volatile ("" ::: "memory");
+
         auto res = sorted_array_from_bufferview(std::move(buffer), m_data, m_bf);
         m_reccnt = res.record_count;
         m_tombstone_cnt = res.tombstone_count;