diff --git a/loopy/kernel/instruction.py b/loopy/kernel/instruction.py
index 1f1b842a2b6bd803b7fa0ffa37daea3a1d76cb6e..fdd8f1d3764ec03ca40a8338dc512b8cd2ae38cf 100644
--- a/loopy/kernel/instruction.py
+++ b/loopy/kernel/instruction.py
@@ -224,7 +224,7 @@ class InstructionBase(ImmutableRecord):
 
         if isinstance(depends_on, str):
             depends_on = frozenset(
-                    s.strip() for s in depends_on.split() if s.strip())
+                    s.strip() for s in depends_on.split(",") if s.strip())
 
         if depends_on_is_final is None:
             depends_on_is_final = False