From 42a989fad8c0f52d5afa482afc5b531ed34887d2 Mon Sep 17 00:00:00 2001
From: Miroslav Crnic <mcrnic@fb.com>
Date: Wed, 11 Oct 2017 01:43:41 -0700
Subject: [PATCH] Add support for clang intrinsic constexpr

Summary: Newer versions of clang >=3.4 support intrinsic constexpr

Reviewed By: Orvid

Differential Revision: D6008856

fbshipit-source-id: 4e40a7032464216d181d76a854cafb2ab4be1be0
---
 folly/Bits.h | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/folly/Bits.h b/folly/Bits.h
index 63eaa4a1..4b71c189 100644
--- a/folly/Bits.h
+++ b/folly/Bits.h
@@ -54,12 +54,11 @@
 
 #pragma once
 
-#if !defined(__clang__) && !(defined(_MSC_VER) && (_MSC_VER < 1900))
-#define FOLLY_INTRINSIC_CONSTEXPR constexpr
-#else
-// GCC and MSVC 2015+ are the only compilers with
-// intrinsics constexpr.
+// MSVC does not support intrinsics constexpr
+#if defined(_MSC_VER)
 #define FOLLY_INTRINSIC_CONSTEXPR const
+#else
+#define FOLLY_INTRINSIC_CONSTEXPR constexpr
 #endif
 
 #include <cassert>
-- 
2.34.1