Add back -polly-detect-unprofitable as alias of -polly-process-unprofitable

This flag was still used in our LNT server. We leave it until it has been
removed from LNT as well.

llvm-svn: 249973
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 775d217..254f0af 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -79,6 +79,11 @@
     cl::location(PollyProcessUnprofitable), cl::init(false), cl::ZeroOrMore,
     cl::cat(PollyCategory));
 
+static cl::alias
+    DetectUnprofitableAlias("polly-detect-unprofitable",
+                            cl::desc("Alias for -polly-process-unprofitable"),
+                            cl::aliasopt(XPollyProcessUnprofitable));
+
 static cl::opt<std::string> OnlyFunction(
     "polly-only-func",
     cl::desc("Only run on functions that contain a certain string"),