diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index 8082595f9..22f60fdde 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -811,7 +811,8 @@ class LLVMIRGenerator:
                 llptr = self.llbuilder.gep(obj, [self.llindex(0), self.llindex(index)],
                                            inbounds=True, name="ptr.{}".format(insn.name))
                 llval = self.llbuilder.load(llptr, name="val.{}".format(insn.name))
-                llval.metadata['invariant.load'] = self.empty_metadata
+                if types.is_instance(typ) and attr not in typ.constant_attributes:
+                    llval.metadata['invariant.load'] = self.empty_metadata
                 return llval
 
     def process_SetAttr(self, insn):