From efdf2e405664163c685127aecec53a21977f8031 Mon Sep 17 00:00:00 2001
From: Hauke Heibel <hauke.heibel@gmail.com>
Date: Thu, 16 Dec 2010 20:08:22 +0100
Subject: [PATCH] Added automatic SSE3/4.1/4.2 support for MSVC.

---
 Eigen/Core | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Eigen/Core b/Eigen/Core
index 4100c435a..d88cdc1a9 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -169,6 +169,22 @@
 // required for __cpuid, needs to be included after cmath
 #if defined(_MSC_VER) && (defined(_M_IX86)||defined(_M_X64))
   #include <intrin.h>
+  // When available, intrin.h pulls in all SSE headers which allows us
+  // to check which SSE level is supported on MSVC systems
+  #ifndef EIGEN_DONT_VECTORIZE
+    #ifdef _INCLUDED_PMM
+      #define EIGEN_VECTORIZE_SSE3
+    #endif
+    #ifdef _INCLUDED_TMM
+      #define EIGEN_VECTORIZE_SSSE3
+    #endif
+    #ifdef _INCLUDED_SMM
+      #define EIGEN_VECTORIZE_SSE4_1
+    #endif
+    #ifdef _INCLUDED_NMM
+      #define EIGEN_VECTORIZE_SSE4_2
+    #endif
+  #endif
 #endif
 
 #if (defined(_CPPUNWIND) || defined(__EXCEPTIONS)) && !defined(EIGEN_NO_EXCEPTIONS)