Update mlir/test/Dialect/GPU/barrier-elimination.mlir

Co-authored-by: Fabian Mora <[email protected]>

Author: ftynse

mlir/test/Dialect/GPU/barrier-elimination.mlir

@@ -188,6 +188,8 @@ func.func @nested_loop_barrier_only() attributes {__parallel_region_boundary_for
   %c0 = arith.constant 0 : index
   %c42 = arith.constant 42 : index
   %c1 = arith.constant 1 : index
+  // Note: the barrier can be removed and as consequence the loops get folded
+  // by the greedy rewriter.
   // CHECK-NOT: scf.for
   // CHECK-NOT: gpu.barrier
   scf.for %j = %c0 to %c42 step %c1 {