Revert D38481 due to missing cmake check for CPU_COUNT

Summary:
This reverts D38481. The change breaks systems with older versions of glibc. It
injects a use of CPU_COUNT() from sched.h without checking to ensure that the
function exists first.

Reviewers:

Subscribers:

llvm-svn: 314922

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/Support/ThreadPool.cpp b/llvm/lib/Support/ThreadPool.cpp
index f1b5bdf40c3..22b7550d497 100644
--- a/llvm/lib/Support/ThreadPool.cpp
+++ b/llvm/lib/Support/ThreadPool.cpp
@@ -14,15 +14,14 @@
 #include "llvm/Support/ThreadPool.h"
 
 #include "llvm/Config/llvm-config.h"
-#include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
 #if LLVM_ENABLE_THREADS
 
-// Default to hardware_concurrency
-ThreadPool::ThreadPool() : ThreadPool(hardware_concurrency()) {}
+// Default to std::thread::hardware_concurrency
+ThreadPool::ThreadPool() : ThreadPool(std::thread::hardware_concurrency()) {}
 
 ThreadPool::ThreadPool(unsigned ThreadCount)
     : ActiveThreads(0), EnableFlag(true) {