diff --git a/loopy/kernel.py b/loopy/kernel.py
index 30aa1c515addeb4b01cf075a0a19f2efc67b76a3..2838d09d00246811d6889ee7d5615ce66df0a920 100644
--- a/loopy/kernel.py
+++ b/loopy/kernel.py
@@ -433,7 +433,13 @@ class LoopKernel(Record):
     def split_dimension(self, name, inner_length, padded_length=None,
             outer_name=None, inner_name=None,
             outer_tag=None, inner_tag=None,
-            outer_slab_increments=(0, -1)):
+            outer_slab_increments=(0, -1), no_slabs=None):
+
+        if name not in self.all_inames():
+            raise ValueError("cannot split loop for unknown variable '%s'" % name)
+
+        if no_slabs:
+            outer_slab_increments = (0, 0)
 
         outer_tag = parse_tag(outer_tag)
         inner_tag = parse_tag(inner_tag)