Do not use negative option name

Instead of -polly-no-tiling, we use -polly-tiling=false to disable tiling.

llvm-svn: 245423
diff --git a/polly/lib/Transform/ScheduleOptimizer.cpp b/polly/lib/Transform/ScheduleOptimizer.cpp
index 4c9c971..9a54c1d 100644
--- a/polly/lib/Transform/ScheduleOptimizer.cpp
+++ b/polly/lib/Transform/ScheduleOptimizer.cpp
@@ -71,14 +71,10 @@
 
 #define DEBUG_TYPE "polly-opt-isl"
 
-namespace polly {
-bool DisablePollyTiling;
-}
-static cl::opt<bool, true>
-    DisableTiling("polly-no-tiling",
-                  cl::desc("Disable tiling in the scheduler"),
-                  cl::location(polly::DisablePollyTiling), cl::init(false),
-                  cl::ZeroOrMore, cl::cat(PollyCategory));
+static cl::opt<bool> EnableTiling("polly-tiling",
+                                  cl::desc("Enable loop tiling"),
+                                  cl::init(true), cl::ZeroOrMore,
+                                  cl::cat(PollyCategory));
 
 static cl::opt<std::string>
     OptimizeDeps("polly-opt-optimize-only",
@@ -283,7 +279,7 @@
     return Node;
   }
 
-  if (!DisableTiling) {
+  if (EnableTiling) {
     auto Ctx = isl_schedule_node_get_ctx(Node);
     auto Sizes = isl_multi_val_zero(isl_space_copy(Space));
     for (unsigned i = 0; i < Dims; i++) {