diff --git a/eigen3-CastXML-support-for-aarch64.patch b/eigen3-CastXML-support-for-aarch64.patch
new file mode 100644
index 0000000..6f17cc0
--- /dev/null
+++ b/eigen3-CastXML-support-for-aarch64.patch
@@ -0,0 +1,54 @@
+From 880fa43b2ba9c25f45ae3ad4871a6aabe558329f Mon Sep 17 00:00:00 2001
+From: Brad King <brad.king@kitware.com>
+Date: Wed, 16 Sep 2020 13:37:27 -0400
+Subject: [PATCH] Add support for CastXML on ARM aarch64
+
+CastXML simulates the preprocessors of other compilers, but actually
+parses the translation unit with an internal Clang compiler.
+Use the same `vld1q_u64` workaround that we do for Clang.
+
+Fixes: #1979
+---
+ Eigen/src/Core/arch/NEON/Complex.h | 4 ++--
+ Eigen/src/Core/util/Macros.h       | 6 ++++++
+ 2 files changed, 8 insertions(+), 2 deletions(-)
+
+Index: eigen-eigen-323c052e1731/Eigen/src/Core/arch/NEON/Complex.h
+===================================================================
+--- eigen-eigen-323c052e1731.orig/Eigen/src/Core/arch/NEON/Complex.h
++++ eigen-eigen-323c052e1731/Eigen/src/Core/arch/NEON/Complex.h
+@@ -17,7 +17,7 @@ namespace internal {
+ 
+ inline uint32x4_t p4ui_CONJ_XOR() {
+ // See bug 1325, clang fails to call vld1q_u64.
+-#if EIGEN_COMP_CLANG
++#if EIGEN_COMP_CLANG || EIGEN_COMP_CASTXML
+   uint32x4_t ret = { 0x00000000, 0x80000000, 0x00000000, 0x80000000 };
+   return ret;
+ #else
+@@ -291,7 +291,7 @@ ptranspose(PacketBlock<Packet2cf,2>& ker
+ #if EIGEN_ARCH_ARM64 && !EIGEN_APPLE_DOUBLE_NEON_BUG
+ 
+ // See bug 1325, clang fails to call vld1q_u64.
+-#if EIGEN_COMP_CLANG
++#if EIGEN_COMP_CLANG || EIGEN_COMP_CASTXML
+   static uint64x2_t p2ul_CONJ_XOR = {0x0, 0x8000000000000000};
+ #else
+   const uint64_t  p2ul_conj_XOR_DATA[] = { 0x0, 0x8000000000000000 };
+Index: eigen-eigen-323c052e1731/Eigen/src/Core/util/Macros.h
+===================================================================
+--- eigen-eigen-323c052e1731.orig/Eigen/src/Core/util/Macros.h
++++ eigen-eigen-323c052e1731/Eigen/src/Core/util/Macros.h
+@@ -35,6 +35,12 @@
+   #define EIGEN_COMP_CLANG 0
+ #endif
+ 
++/// \internal EIGEN_COMP_CASTXML set to 1 if being preprocessed by CastXML
++#if defined(__castxml__)
++  #define EIGEN_COMP_CASTXML 1
++#else
++  #define EIGEN_COMP_CASTXML 0
++#endif
+ 
+ /// \internal EIGEN_COMP_LLVM set to 1 if the compiler backend is llvm
+ #if defined(__llvm__)
diff --git a/eigen3.changes b/eigen3.changes
index 157efae..bf49115 100644
--- a/eigen3.changes
+++ b/eigen3.changes
@@ -1,3 +1,11 @@
+-------------------------------------------------------------------
+Thu Sep 17 12:23:42 UTC 2020 - Atri Bhattacharya <badshah400@gmail.com>
+
+- Add eigen3-CastXML-support-for-aarch64.patch to support CastXML
+  on aarch64 [https://gitlab.com/libeigen/eigen/-/issues/1979];
+  patch taken from upstream commit and rebased to apply without
+  fuzz.
+
 -------------------------------------------------------------------
 Mon Aug  5 23:28:16 UTC 2019 - Stefan Brüns <stefan.bruens@rwth-aachen.de>
 
diff --git a/eigen3.spec b/eigen3.spec
index 7f38ded..3d0027a 100644
--- a/eigen3.spec
+++ b/eigen3.spec
@@ -1,7 +1,7 @@
 #
 # spec file for package eigen3
 #
-# Copyright (c) 2019 SUSE LINUX GmbH, Nuernberg, Germany.
+# Copyright (c) 2020 SUSE LLC
 #
 # All modifications and additions to the file contributed by third parties
 # remain the property of their copyright owners, unless otherwise agreed
@@ -31,7 +31,7 @@ Release:        0
 Summary:        C++ Template Library for Linear Algebra
 License:        MPL-2.0 AND LGPL-2.1-only AND LGPL-2.1-or-later AND BSD-3-Clause
 Group:          Development/Libraries/C and C++
-Url:            http://eigen.tuxfamily.org/
+URL:            http://eigen.tuxfamily.org/
 Source0:        https://bitbucket.org/eigen/eigen/get/%{version}.tar.bz2#/%{pkgname}-%{version}.tar.bz2
 Patch0:         0001-Disable-Altivec-for-ppc64le.patch
 Patch1:         0001-Do-stack-allignment-on-ppc.patch
@@ -41,6 +41,8 @@ Patch2:         eigen_pkgconfig.patch
 Patch3:         01_install_FindEigen3.patch
 # PATCH-FIX-OPENSUSE eigen3-3.3.1-fixcmake.patch -- Fix double {prefix} as we use INCLUDE_INSTALL_DIR with {_includedir}
 Patch4:         eigen3-3.3.1-fixcmake.patch
+# PATCH-FIX-UPSTREAM eigen3-CastXML-support-for-aarch64.patch badshah400@gmail.com -- Add CastXML support for ARM aarch64 [https://gitlab.com/libeigen/eigen/-/issues/1979]
+Patch5:         eigen3-CastXML-support-for-aarch64.patch
 BuildRequires:  adolc-devel
 BuildRequires:  cmake
 BuildRequires:  fftw3-devel
@@ -102,6 +104,7 @@ for Linear Algebra
 %patch2 -p1
 %patch3 -p1
 %patch4 -p1
+%patch5 -p1
 
 # Fix rpmlint warning "wrong-file-end-of-line-encoding"
 sed -i 's/\r$//' COPYING.MINPACK