From 8d4d85161e2b8e410c8a196b42f6a78c43268771 Mon Sep 17 00:00:00 2001
From: vanhoucke <vanhoucke@google.com>
Date: Fri, 19 Jun 2015 15:53:30 +0000
Subject: [PATCH] Fix undefined behavior. When resizing a default-constructed
 SparseArray, we end up calling memcpy(ptr, 0, 0), which is technically UB and
 gets caught by static analysis.

---
 Eigen/src/SparseCore/CompressedStorage.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/SparseCore/CompressedStorage.h b/Eigen/src/SparseCore/CompressedStorage.h
index a667cb56e..e54e5c924 100644
--- a/Eigen/src/SparseCore/CompressedStorage.h
+++ b/Eigen/src/SparseCore/CompressedStorage.h
@@ -208,8 +208,10 @@ class CompressedStorage
       Index* newIndices = new Index[size];
       size_t copySize = (std::min)(size, m_size);
       // copy
-      internal::smart_copy(m_values, m_values+copySize, newValues);
-      internal::smart_copy(m_indices, m_indices+copySize, newIndices);
+      if (copySize>0) {
+        internal::smart_copy(m_values, m_values+copySize, newValues);
+        internal::smart_copy(m_indices, m_indices+copySize, newIndices);
+      }
       // delete old stuff
       delete[] m_values;
       delete[] m_indices;