From 45b09e7625ae3d121aa8586b65db906a8da3ec93 Mon Sep 17 00:00:00 2001
From: Yann Collet <cyan@fb.com>
Date: Thu, 1 Mar 2018 15:02:18 -0800
Subject: [PATCH] limit DYNAMIC_BMI2 to gcc >= 4.8

attribute bmi2 not supported by gcc 4.4
---
 lib/common/compiler.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/common/compiler.h b/lib/common/compiler.h
index 24f35328..63d32258 100644
--- a/lib/common/compiler.h
+++ b/lib/common/compiler.h
@@ -71,10 +71,11 @@
 #endif
 
 /* Enable runtime BMI2 dispatch based on the CPU.
- * Enabled for clang/gcc on x86 when BMI2 isn't enabled by default.
+ * Enabled for clang & gcc >=4.8 on x86 when BMI2 isn't enabled by default.
  */
 #ifndef DYNAMIC_BMI2
-  #if defined(__GNUC__) && (defined(__x86_64__) || defined(_M_X86)) && !defined(__BMI2__)
+  #if defined(__GNUC__) && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) \
+      && (defined(__x86_64__) || defined(_M_X86)) && !defined(__BMI2__)
   #  define DYNAMIC_BMI2 1
   #else
   #  define DYNAMIC_BMI2 0