Fix two compiler warnings

One of them actually pointed to an invalid condition in an assert.

llvm-svn: 136657
diff --git a/polly/lib/ScheduleOptimizer.cpp b/polly/lib/ScheduleOptimizer.cpp
index c9982cd..13bacc0 100644
--- a/polly/lib/ScheduleOptimizer.cpp
+++ b/polly/lib/ScheduleOptimizer.cpp
@@ -213,7 +213,7 @@
 				int scheduleDimensions,
 				int parameterDimensions,
 				int vectorWidth = 4) {
-  assert (0 <= vectorDimension < scheduleDimensions);
+  assert (0 <= vectorDimension && vectorDimension < scheduleDimensions);
 
   isl_dim *dim = isl_dim_alloc(ctx, parameterDimensions, scheduleDimensions,
 			       scheduleDimensions + 2);