1From 8bee07de2d0078373f0f1a72e924d7808ddf03e0 Mon Sep 17 00:00:00 2001
2From: Khem Raj <raj.khem@gmail.com>
3Date: Mon, 18 Nov 2019 17:00:29 -0800
4Subject: [PATCH] Check for atomic<double> intrinsics
5
6On some architectures e.g. x86/32bit gcc decides to inline calls to
7double atomic variables but clang does not and defers it to libatomic
8therefore detect if clang can use built-ins for atomic<double> if not
9then link libatomic, this helps building clangd for x86 on linux systems
10with gcc runtime
11
12Signed-off-by: Khem Raj <raj.khem@gmail.com>
13---
14 llvm/cmake/modules/CheckAtomic.cmake | 3 ++-
15 1 file changed, 2 insertions(+), 1 deletion(-)
16
17diff --git a/llvm/cmake/modules/CheckAtomic.cmake b/llvm/cmake/modules/CheckAtomic.cmake
18index 3c5ba72993a3..34a1b950bbed 100644
19--- a/llvm/cmake/modules/CheckAtomic.cmake
20+++ b/llvm/cmake/modules/CheckAtomic.cmake
21@@ -30,10 +30,11 @@ function(check_working_cxx_atomics64 varname)
22 #include <atomic>
23 #include <cstdint>
24 std::atomic<uint64_t> x (0);
25+std::atomic<double> y (0);
26 int main() {
27   uint64_t i = x.load(std::memory_order_relaxed);
28   (void)i;
29-  return 0;
30+  return int(y);
31 }
32 " ${varname})
33   set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
34