From 357cec385d4f44385b24c299a601afc811abd9b7 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Thu, 14 Jul 2016 14:10:14 +0200
Subject: [PATCH] MdePkg: avoid __builtin_unreachable() on GCC v4.4

GCC v4.4 does not implement __builtin_unreachable(), so avoid using
it when building with this version or earlier.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-By: Liming Gao <liming.gao@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
---
 MdePkg/Include/Base.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/MdePkg/Include/Base.h b/MdePkg/Include/Base.h
index 858385828d..7dbf9386b6 100644
--- a/MdePkg/Include/Base.h
+++ b/MdePkg/Include/Base.h
@@ -89,10 +89,11 @@ VERIFY_SIZE_OF (CHAR16, 2);
 // warnings.
 //
 #ifndef UNREACHABLE
-  #ifdef __GNUC__
+  #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 4)
     ///
     /// Signal compilers and analyzers that this call is not reachable.  It is
     /// up to the compiler to remove any code past that point.
+    /// Not implemented by GCC 4.4 or earlier.
     ///
     #define UNREACHABLE()  __builtin_unreachable ()
   #elif defined (__has_feature)