From ec6ca4eae90b0d7699817c1d7c10920fe1a641c9 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 25 Jul 2016 15:17:45 +0200
Subject: [PATCH] bug #1249: enable use of __builtin_prefetch for GCC, clang,
 and ICC only.

---
 Eigen/src/Core/GenericPacketMath.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/Core/GenericPacketMath.h b/Eigen/src/Core/GenericPacketMath.h
index 5f783ebee..c6e93bbb0 100644
--- a/Eigen/src/Core/GenericPacketMath.h
+++ b/Eigen/src/Core/GenericPacketMath.h
@@ -183,8 +183,8 @@ template<typename Scalar, typename Packet> inline void pstoreu(Scalar* to, const
 /** \internal tries to do cache prefetching of \a addr */
 template<typename Scalar> inline void prefetch(const Scalar* addr)
 {
-#if !defined(_MSC_VER)
-__builtin_prefetch(addr);
+#if (!EIGEN_COMP_MSVC) && (EIGEN_COMP_GNUC || EIGEN_COMP_CLANG || EIGEN_COMP_ICC)
+  __builtin_prefetch(addr);
 #endif
 }