diff --git a/artiq/compiler/ir.py b/artiq/compiler/ir.py
index b7fb18402..e1f370ba8 100644
--- a/artiq/compiler/ir.py
+++ b/artiq/compiler/ir.py
@@ -500,7 +500,10 @@ class Function:
 # Python-specific SSA IR classes
 
 class TEnvironment(types.TMono):
-    def __init__(self, vars, outer=None):
+    def __init__(self, name, vars, outer=None):
+        assert isinstance(name, str)
+        self.env_name = name # for readable type names in LLVM IR
+
         if outer is not None:
             assert isinstance(outer, TEnvironment)
             env = OrderedDict({"$outer": outer})
diff --git a/artiq/compiler/transforms/artiq_ir_generator.py b/artiq/compiler/transforms/artiq_ir_generator.py
index e3a6ae000..3190c1e67 100644
--- a/artiq/compiler/transforms/artiq_ir_generator.py
+++ b/artiq/compiler/transforms/artiq_ir_generator.py
@@ -181,11 +181,12 @@ class ARTIQIRGenerator(algorithm.Visitor):
             entry = self.add_block("entry")
             old_block, self.current_block = self.current_block, entry
 
-            env = self.append(ir.Alloc([], ir.TEnvironment(node.typing_env), name="env"))
+            env_type = ir.TEnvironment(name=func.name, vars=node.typing_env)
+            env = self.append(ir.Alloc([], env_type, name="env"))
             old_env, self.current_env = self.current_env, env
 
-            priv_env = self.append(ir.Alloc([], ir.TEnvironment({ "$return": typ.ret }),
-                                            name="privenv"))
+            priv_env_type = ir.TEnvironment(name=func.name + ".priv", vars={ "$return": typ.ret })
+            priv_env = self.append(ir.Alloc([], priv_env_type, name="privenv"))
             old_priv_env, self.current_private_env = self.current_private_env, priv_env
 
             self.generic_visit(node)
@@ -264,13 +265,15 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 {var: node.typing_env[var]
                  for var in node.typing_env
                   if var not in node.globals_in_scope}
-            env_type = ir.TEnvironment(env_without_globals, self.current_env.type)
+            env_type = ir.TEnvironment(name=func.name,
+                                       vars=env_without_globals, outer=self.current_env.type)
             env = self.append(ir.Alloc([], env_type, name="env"))
             old_env, self.current_env = self.current_env, env
 
             if not is_lambda:
-                priv_env = self.append(ir.Alloc([], ir.TEnvironment({ "$return": typ.ret }),
-                                                name="privenv"))
+                priv_env_type = ir.TEnvironment(name=func.name + ".priv",
+                                                vars={ "$return": typ.ret })
+                priv_env = self.append(ir.Alloc([], priv_env_type, name="privenv"))
                 old_priv_env, self.current_private_env = self.current_private_env, priv_env
 
             self.append(ir.SetLocal(env, "$outer", env_arg))
@@ -1092,7 +1095,9 @@ class ARTIQIRGenerator(algorithm.Visitor):
         result = self.append(ir.Alloc([length], node.type))
 
         try:
-            env_type = ir.TEnvironment(node.typing_env, self.current_env.type)
+            gen_suffix = ".gen.{}.{}".format(node.loc.line(), node.loc.column())
+            env_type = ir.TEnvironment(name=self.current_function.name + gen_suffix,
+                                       vars=node.typing_env, outer=self.current_env.type)
             env = self.append(ir.Alloc([], env_type, name="env.gen"))
             old_env, self.current_env = self.current_env, env
 
diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index f057c8b53..127fe32c0 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -256,8 +256,10 @@ class LLVMIRGenerator:
         elif ir.is_option(typ):
             return ll.LiteralStructType([lli1, self.llty_of_type(typ.params["inner"])])
         elif ir.is_environment(typ):
-            llty = ll.LiteralStructType([self.llty_of_type(typ.params[name])
-                                         for name in typ.params])
+            llty = self.llcontext.get_identified_type("env.{}".format(typ.env_name))
+            if llty.elements is None:
+                llty.elements = [self.llty_of_type(typ.params[name]) for name in typ.params]
+
             if bare:
                 return llty
             else: