diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index d67d582ad..fa619d48c 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -150,8 +150,9 @@ class LLVMIRGenerator:
             ll.Constant(lli64, 1)
         ])
 
-        assert self.lldatalayout in "eE"
-        self.little_endian = self.lldatalayout[0] == "e"
+        data_layout = str(self.lldatalayout)
+        assert data_layout[0] in "eE"
+        self.little_endian = data_layout[0] == "e"
 
     def needs_sret(self, lltyp, may_be_large=True):
         if isinstance(lltyp, ll.VoidType):