Introduce Regex::isLiteralERE function.

This will be used to implement an optimisation for literal entries
in special case lists.

Differential Revision: http://llvm-reviews.chandlerc.com/D1278

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187731 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Support/RegexTest.cpp b/unittests/Support/RegexTest.cpp
index 3577d10..02869b3 100644
--- a/unittests/Support/RegexTest.cpp
+++ b/unittests/Support/RegexTest.cpp
@@ -112,4 +112,19 @@
   EXPECT_EQ(Error, "invalid backreference string '100'");
 }
 
+TEST_F(RegexTest, IsLiteralERE) {
+  EXPECT_TRUE(Regex::isLiteralERE("abc"));
+  EXPECT_FALSE(Regex::isLiteralERE("a(bc)"));
+  EXPECT_FALSE(Regex::isLiteralERE("^abc"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc$"));
+  EXPECT_FALSE(Regex::isLiteralERE("a|bc"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc*"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc+"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc?"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc."));
+  EXPECT_FALSE(Regex::isLiteralERE("a[bc]"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc\\1"));
+  EXPECT_FALSE(Regex::isLiteralERE("abc{1,2}"));
+}
+
 }