diff --git a/loopy/target/c/__init__.py b/loopy/target/c/__init__.py
index e4835a3638b43619f9b93f45958382218b701642..7cc53d84038d1a10836fc28ecc5bc74a9e4fb209 100644
--- a/loopy/target/c/__init__.py
+++ b/loopy/target/c/__init__.py
@@ -486,6 +486,8 @@ class CASTBuilder(ASTBuilderBase):
                             * product(si for si in idi.shape))
 
         ecm = self.get_expression_to_code_mapper(codegen_state)
+        from loopy.symbolic import ConstantFoldingMapper
+        cfm = ConstantFoldingMapper()
 
         for bs_name, bs_sizes in sorted(six.iteritems(base_storage_sizes)):
             bs_var_decl = Value("char", bs_name)
@@ -494,6 +496,7 @@ class CASTBuilder(ASTBuilderBase):
                     bs_var_decl, single_valued(base_storage_to_scope[bs_name]))
 
             # FIXME: Could try to use isl knowledge to simplify max.
+            bs_sizes = tuple(cfm.evaluate(s) for s in bs_sizes)
             if all(isinstance(bs, int) for bs in bs_sizes):
                 bs_size_max = max(bs_sizes)
             else: