From 21577c0682a8c0a3073cf970eeb3fd8dde2bcb21 Mon Sep 17 00:00:00 2001
From: Teresa Johnson <tejohnson@google.com>
Date: Fri, 18 Dec 2015 22:59:35 +0000
Subject: [PATCH] Remove possibility of failures to due race in ThreadPool
 unittest

Remove all checks that required main thread to run faster than tasks in
ThreadPool, and yields which are now unnecessary. This should fix some
bot failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256056 91177308-0d34-0410-b5e6-96231b3b80d8
---
 unittests/Support/ThreadPool.cpp | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/unittests/Support/ThreadPool.cpp b/unittests/Support/ThreadPool.cpp
index 5fb14537568..b0e33c10876 100644
--- a/unittests/Support/ThreadPool.cpp
+++ b/unittests/Support/ThreadPool.cpp
@@ -18,18 +18,6 @@
 #include "gtest/gtest.h"
 
 using namespace llvm;
-using namespace std::chrono;
-
-/// Try best to make this thread not progress faster than the main thread
-static void yield() {
-#ifdef LLVM_ENABLE_THREADS
-  std::this_thread::yield();
-#endif
-  std::this_thread::sleep_for(milliseconds(200));
-#ifdef LLVM_ENABLE_THREADS
-  std::this_thread::yield();
-#endif
-}
 
 // Fixture for the unittests, allowing to *temporarily* disable the unittests
 // on a particular platform
@@ -83,11 +71,9 @@ TEST_F(ThreadPoolTest, AsyncBarrier) {
   ThreadPool Pool;
   for (size_t i = 0; i < 5; ++i) {
     Pool.async([&checked_in, i] {
-      yield();
       ++checked_in;
     });
   }
-  ASSERT_EQ(0, checked_in);
   Pool.wait();
   ASSERT_EQ(5, checked_in);
 }
@@ -111,13 +97,10 @@ TEST_F(ThreadPoolTest, Async) {
   CHECK_UNSUPPORTED();
   ThreadPool Pool;
   std::atomic_int i{0};
-  // sleep here just to ensure that the not-equal is correct.
   Pool.async([&i] {
-    yield();
     ++i;
   });
   Pool.async([&i] { ++i; });
-  ASSERT_NE(2, i.load());
   Pool.wait();
   ASSERT_EQ(2, i.load());
 }
@@ -126,14 +109,11 @@ TEST_F(ThreadPoolTest, GetFuture) {
   CHECK_UNSUPPORTED();
   ThreadPool Pool;
   std::atomic_int i{0};
-  // sleep here just to ensure that the not-equal is correct.
   Pool.async([&i] {
-    yield();
     ++i;
   });
   // Force the future using get()
   Pool.async([&i] { ++i; }).get();
-  ASSERT_NE(2, i.load());
   Pool.wait();
   ASSERT_EQ(2, i.load());
 }
@@ -147,11 +127,9 @@ TEST_F(ThreadPoolTest, PoolDestruction) {
     ThreadPool Pool;
     for (size_t i = 0; i < 5; ++i) {
       Pool.async([&checked_in, i] {
-        yield();
         ++checked_in;
       });
     }
-    ASSERT_EQ(0, checked_in);
   }
   ASSERT_EQ(5, checked_in);
 }
-- 
2.34.1