clang-format: Fix corner case in OpenMP pragma formatting.

Before:
  #pragma omp reduction( | : var)
After:
  #pragma omp reduction(| : var)

llvm-svn: 187892
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index fe10de9..2b1b94c 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5532,6 +5532,11 @@
                BreakBeforeBrace);
 }
 
+TEST_F(FormatTest, UnderstandsPragmas) {
+  verifyFormat("#pragma omp reduction(| : var)");
+  verifyFormat("#pragma omp reduction(+ : var)");
+}
+
 bool allStylesEqual(ArrayRef<FormatStyle> Styles) {
   for (size_t i = 1; i < Styles.size(); ++i)
     if (!(Styles[0] == Styles[i]))