diff --git a/loopy/codegen/loop.py b/loopy/codegen/loop.py
index 0110a06095fa0bd690045f050136027d7bed3a28..450c43786fa1d2b8a4fb5093bc002ae856298cbb 100644
--- a/loopy/codegen/loop.py
+++ b/loopy/codegen/loop.py
@@ -286,11 +286,10 @@ def set_up_hw_parallel_loops(codegen_state, schedule_index, next_func,
     bounds = kernel.get_iname_bounds(iname)
     domain = kernel.get_inames_domain(iname)
 
-    # It's ok to find a bound that's too "loose". The conditional
-    # generators will mop up after us.
-    from loopy.isl_helpers import static_min_of_pw_aff
-    lower_bound = static_min_of_pw_aff(bounds.lower_bound_pw_aff,
-            constants_only=False)
+    # Approximating this is not OK, since the loop may wind up
+    # starting too low--and with a fixed length, it'll iterate
+    # over the wrong domain.
+    lower_bound = bounds.lower_bound_pw_aff
 
     # These bounds are 'implemented' by the hardware. Make sure
     # that the downstream conditional generators realize that.