diff --git a/loopy/codegen/loop.py b/loopy/codegen/loop.py
index 1b4e057589360d2c663e7cc0fdddf40f093f2c06..3e18e997c517749a61eb6fc616806e07d682137c 100644
--- a/loopy/codegen/loop.py
+++ b/loopy/codegen/loop.py
@@ -129,19 +129,15 @@ def generate_unroll_loop(kernel, sched_index, codegen_state):
     tag = kernel.iname_to_tag.get(iname)
 
     bounds = kernel.get_iname_bounds(iname)
-    from loopy.isl_helpers import static_max_of_pw_aff
+    from loopy.isl_helpers import (
+            static_max_of_pw_aff, static_value_of_pw_aff)
     from loopy.symbolic import pw_aff_to_expr
 
     length = int(pw_aff_to_expr(
         static_max_of_pw_aff(bounds.size, constants_only=True)))
-    lower_bound_pw_aff_pieces = bounds.lower_bound_pw_aff.coalesce().get_pieces()
-
-    if len(lower_bound_pw_aff_pieces) > 1:
-        raise NotImplementedError("lower bound for unroll of '%s'"
-                "needs conditional/has more than one piece:\n%s" % (
-                    iname, "\n".join(str(piece) for piece in lower_bound_pw_aff_pieces)))
-
-    (_, lower_bound_aff), = lower_bound_pw_aff_pieces
+    lower_bound_aff = static_value_of_pw_aff(
+            bounds.lower_bound_pw_aff.coalesce(),
+            constants_only=False)
 
     from loopy.kernel import UnrollTag
     if isinstance(tag, UnrollTag):
diff --git a/loopy/isl_helpers.py b/loopy/isl_helpers.py
index d1d42ffcfcdbd03e86389c39c2313c8684ff61d8..84cebabcbf346a499d31602807af65872c6c5aa2 100644
--- a/loopy/isl_helpers.py
+++ b/loopy/isl_helpers.py
@@ -156,6 +156,7 @@ def static_extremum_of_pw_aff(pw_aff, constants_only, set_method, what):
         return pieces[0][1]
 
     agg_domain = pw_aff.get_aggregate_domain()
+
     for set, candidate_aff in pieces:
         if constants_only and not candidate_aff.is_cst():
             continue
@@ -177,6 +178,10 @@ def static_max_of_pw_aff(pw_aff, constants_only):
     return static_extremum_of_pw_aff(pw_aff, constants_only, isl.PwAff.le_set,
             "maximum")
 
+def static_value_of_pw_aff(pw_aff, constants_only):
+    return static_extremum_of_pw_aff(pw_aff, constants_only, isl.PwAff.eq_set,
+            "value")
+