diff --git a/loopy/codegen/bounds.py b/loopy/codegen/bounds.py
index 3beb9a2ee78b7d374997367162b51cc50d87410b..a1c2a5acb4fe7f4bca1d1b566808599ec0b33760 100644
--- a/loopy/codegen/bounds.py
+++ b/loopy/codegen/bounds.py
@@ -63,8 +63,8 @@ def get_bounds_checks(domain, check_inames, implemented_domain,
         result = result.compute_divs()
 
     from loopy.isl_helpers import convexify
-    result = convexify(result).get_constraints()
-    return result
+    result = convexify(result)
+    return result.get_constraints()
 
 # }}}
 
diff --git a/loopy/codegen/control.py b/loopy/codegen/control.py
index 57257fe1ba50596724267f4825da6e1efea9a860..013ec5d099b892799ad1d7b83dcf91daf4db9a16 100644
--- a/loopy/codegen/control.py
+++ b/loopy/codegen/control.py
@@ -246,7 +246,7 @@ def build_loop_nest(kernel, sched_index, codegen_state):
 
             bounds_checks = bounds_check_cache(only_unshared_inames)
 
-            if bounds_checks or candidate_group_length == 1:
+            if bounds_checks or bounds_checks is None or candidate_group_length == 1:
                 # length-1 must always be an option to reach the recursion base
                 # case below
                 found_hoists.append((candidate_group_length, bounds_checks))
@@ -271,27 +271,35 @@ def build_loop_nest(kernel, sched_index, codegen_state):
 
         if check_set is None:
             new_codegen_state = codegen_state
+            is_empty = False
         else:
+            is_empty = check_set.is_empty()
             new_codegen_state = codegen_state.intersect(check_set)
 
-        if group_length == 1:
-            # group only contains starting schedule item
-            result = [generate_code_for_sched_index(
-                kernel, sched_index, new_codegen_state)]
+        if is_empty:
+            result = []
         else:
-            # recurse with a bigger done_group_lengths
-            result = build_insn_group(
-                    sched_indices_and_cond_inames[0:group_length],
-                    new_codegen_state,
-                    done_group_lengths=done_group_lengths | set([group_length]))
-
-        if bounds_checks:
-            from loopy.codegen import wrap_in_if
-            from loopy.codegen.bounds import constraint_to_code
-            result = [wrap_in_if(
-                    [constraint_to_code(codegen_state.c_code_mapper, cns)
-                        for cns in bounds_checks],
-                    gen_code_block(result))]
+            if group_length == 1:
+                # group only contains starting schedule item
+                result = [generate_code_for_sched_index(
+                    kernel, sched_index, new_codegen_state)]
+                if result == [None]:
+                    result = []
+            else:
+                # recurse with a bigger done_group_lengths
+                result = build_insn_group(
+                        sched_indices_and_cond_inames[0:group_length],
+                        new_codegen_state,
+                        done_group_lengths=done_group_lengths | set([group_length]))
+
+            if bounds_checks:
+                from loopy.codegen import wrap_in_if
+                from loopy.codegen.bounds import constraint_to_code
+                result = [
+                        wrap_in_if(
+                            [constraint_to_code(codegen_state.c_code_mapper, cns)
+                                for cns in bounds_checks],
+                            gen_code_block(result))]
 
         return result + build_insn_group(
                 sched_indices_and_cond_inames[group_length:], codegen_state)
diff --git a/loopy/codegen/instruction.py b/loopy/codegen/instruction.py
index f333baadb765df8466c9193c6ac526e3c481a795..1dcbf8906baa376a77f0b51c8bbcf8122a149367 100644
--- a/loopy/codegen/instruction.py
+++ b/loopy/codegen/instruction.py
@@ -40,6 +40,9 @@ def wrap_in_bounds_checks(ccm, domain, check_inames, implemented_domain, stmt):
             bounds_check_set, implemented_domain)
     new_implemented_domain = new_implemented_domain & bounds_check_set
 
+    if bounds_check_set.is_empty():
+        return None, None
+
     condition_codelets = [constraint_to_code(ccm, cns) for cns in bounds_checks]
 
     if condition_codelets:
@@ -61,7 +64,6 @@ def generate_instruction_code(kernel, insn, codegen_state):
 
 
 def generate_expr_instruction_code(kernel, insn, codegen_state):
-
     ccm = codegen_state.c_code_mapper
 
     expr = insn.expression
@@ -82,6 +84,9 @@ def generate_expr_instruction_code(kernel, insn, codegen_state):
             codegen_state.implemented_domain,
             insn_code)
 
+    if insn_code is None:
+        return None
+
     result = GeneratedInstruction(
         insn_id=insn.id,
         implemented_domain=impl_domain,
@@ -139,6 +144,9 @@ def generate_c_instruction_code(kernel, insn, codegen_state):
             codegen_state.implemented_domain,
             Block(body))
 
+    if insn_code is None:
+        return None
+
     return GeneratedInstruction(
         insn_id=insn.id,
         implemented_domain=impl_domain,