Thread safety analysis: handle CFG blocks which call functions marked as noreturn.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151944 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ThreadSafety.cpp b/lib/Analysis/ThreadSafety.cpp
index 1370d5d..40ad79b 100644
--- a/lib/Analysis/ThreadSafety.cpp
+++ b/lib/Analysis/ThreadSafety.cpp
@@ -1526,6 +1526,10 @@
       if (*PI == 0 || !VisitedBlocks.alreadySet(*PI))
         continue;
 
+      // Ignore edges from blocks that can't return.
+      if ((*PI)->hasNoReturnElement())
+        continue;
+
       // If the previous block ended in a 'continue' or 'break' statement, then
       // a difference in locksets is probably due to a bug in that block, rather
       // than in some other predecessor. In that case, keep the other
diff --git a/test/SemaCXX/warn-thread-safety-analysis.cpp b/test/SemaCXX/warn-thread-safety-analysis.cpp
index a7c1c00..78a276c 100644
--- a/test/SemaCXX/warn-thread-safety-analysis.cpp
+++ b/test/SemaCXX/warn-thread-safety-analysis.cpp
@@ -2114,3 +2114,20 @@
 
 }  // end namespace InvalidNonStatic
 
+
+namespace NoReturnTest {
+
+bool condition();
+void fatal() __attribute__((noreturn));
+
+Mutex mu_;
+
+void test1() {
+  MutexLock lock(&mu_);
+  if (condition()) {
+    fatal();
+    return;
+  }
+}
+
+};