diff --git a/eigen3-5d9e44.patch b/eigen3-5d9e44.patch
new file mode 100644
index 0000000..22dee62
--- /dev/null
+++ b/eigen3-5d9e44.patch
@@ -0,0 +1,20 @@
+# HG changeset patch
+# User Gael Guennebaud <g.gael@free.fr>
+# Date 1418910820 -3600
+# Branch 3.2
+# Node ID 5d9e54445535570698f7465582c7256d9d74c004
+# Parent  9716ca6de21838927484f3c33050648bac890ac3
+rm explicit keyword introduced by backporting another change
+
+diff --git a/Eigen/src/Geometry/Rotation2D.h b/Eigen/src/Geometry/Rotation2D.h
+--- a/Eigen/src/Geometry/Rotation2D.h
++++ b/Eigen/src/Geometry/Rotation2D.h
+@@ -59,7 +59,7 @@
+ public:
+ 
+   /** Construct a 2D counter clock wise rotation from the angle \a a in radian. */
+-  explicit inline Rotation2D(const Scalar& a) : m_angle(a) {}
++  inline Rotation2D(const Scalar& a) : m_angle(a) {}
+   
+   /** Default constructor wihtout initialization. The represented rotation is undefined. */
+   Rotation2D() {}
diff --git a/eigen3.spec b/eigen3.spec
index f316b76..5a0a930 100644
--- a/eigen3.spec
+++ b/eigen3.spec
@@ -8,7 +8,7 @@
 
 Name:           eigen3
 Version:        3.2.3
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        A lightweight C++ template library for vector and matrix math
 
 Group:          Development/Libraries
@@ -20,6 +20,8 @@ Source0:        eigen-%{version}.tar.bz2
 
 # Fix build with recent suitesparse versions
 Patch0:         eigen-3.2.3_suitesparse.patch
+# Backport of upstream regression fix in Rotation2D.
+Patch1:         eigen3-5d9e44.patch
 
 BuildRequires:  atlas-devel
 BuildRequires:  fftw-devel
@@ -62,6 +64,7 @@ Developer documentation for Eigen.
 %prep
 %setup -q -n eigen-eigen-%{commit}
 %patch0 -p1
+%patch1 -p1
 
 %build
 mkdir %{_target_platform}
@@ -97,6 +100,9 @@ make -C %{_target_platform} %{?_smp_mflags} test ARGS="-V" || exit 0
 %doc %{_target_platform}/doc/html
 
 %changelog
+* Mon Jan 05 2015 Rich Mattes <richmattes@gmail.com> - 3.2.3-2
+- Backport upstream Rotation2D fix
+
 * Thu Dec 18 2014 Sandro Mani <manisandro@gmail.com> - 3.2.3-1
 - Update to release 3.2.3
 - Drop upstreamed eigen3-ppc64.patch