From 1939c971a3dbdbec9f2539406f61d094c9bead42 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Tue, 3 Apr 2018 14:36:27 +0200
Subject: [PATCH] AVX512: _mm512_rsqrt28_ps is available for AVX512ER only
 (grafted from 40b4bf3d32265152ae26c2f630f6f70e5d676f3d )

---
 Eigen/Core                                 | 3 +++
 Eigen/src/Core/arch/AVX512/MathFunctions.h | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Eigen/Core b/Eigen/Core
index 2b2ab44d1..4d4901e03 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -171,6 +171,9 @@
       #ifdef __AVX512DQ__
         #define EIGEN_VECTORIZE_AVX512DQ
       #endif
+      #ifdef __AVX512ER__
+        #define EIGEN_VECTORIZE_AVX512ER
+      #endif
     #endif
 
     // include files
diff --git a/Eigen/src/Core/arch/AVX512/MathFunctions.h b/Eigen/src/Core/arch/AVX512/MathFunctions.h
index 4695fbc81..61434a33e 100644
--- a/Eigen/src/Core/arch/AVX512/MathFunctions.h
+++ b/Eigen/src/Core/arch/AVX512/MathFunctions.h
@@ -375,7 +375,7 @@ prsqrt<Packet8d>(const Packet8d& _x) {
   // Insert NaNs and Infs in all the right places.
   return _mm512_mask_blend_pd(le_zero_mask, x, infs_and_nans);
 }
-#else
+#elif defined(EIGEN_VECTORIZE_AVX512ER)
 template <>
 EIGEN_STRONG_INLINE Packet16f prsqrt<Packet16f>(const Packet16f& x) {
   return _mm512_rsqrt28_ps(x);