From 28a5c36d1dbab092a4c2a7544a5036bb759d0ffe Mon Sep 17 00:00:00 2001
From: Markus Kowalewski <markus.kowalewski@fysik.su.se>
Date: Tue, 23 Apr 2019 16:00:54 +0200
Subject: [PATCH] openblas: turn off AVX512 optimizations

The AVX512 optimization has a bug in openblas-0.3.5
and can also lead to slower code on Xeon Silver CPUs.

See https://github.com/xianyi/OpenBLAS/issues/1955
and https://github.com/xianyi/OpenBLAS/issues/2029

(cherry picked from commit 7035aa7de4fa8668b6d7feab7b1ed58015689d09)
---
 pkgs/development/libraries/science/math/openblas/default.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkgs/development/libraries/science/math/openblas/default.nix b/pkgs/development/libraries/science/math/openblas/default.nix
index 2ae3bd2b9c83..fd0ee3f23380 100644
--- a/pkgs/development/libraries/science/math/openblas/default.nix
+++ b/pkgs/development/libraries/science/math/openblas/default.nix
@@ -58,6 +58,7 @@ let
       BINARY = 64;
       TARGET = setTarget "ATHLON";
       DYNAMIC_ARCH = true;
+      NO_AVX512 = true;
       USE_OPENMP = true;
     };
   };