diff --git a/artiq/compiler/ir.py b/artiq/compiler/ir.py
index 8bc84e598..88ef3a151 100644
--- a/artiq/compiler/ir.py
+++ b/artiq/compiler/ir.py
@@ -135,6 +135,7 @@ class NamedValue(Value):
     def __init__(self, typ, name):
         super().__init__(typ)
         self.name, self.function = name, None
+        self.is_removed = False
 
     def set_name(self, new_name):
         if self.function is not None:
@@ -235,7 +236,7 @@ class Instruction(User):
         self.drop_references()
         # Check this after drop_references in case this
         # is a self-referencing phi.
-        assert not any(self.uses)
+        assert all(use.is_removed for use in self.uses)
 
     def replace_with(self, value):
         self.replace_all_uses_with(value)
@@ -370,7 +371,7 @@ class BasicBlock(NamedValue):
         self.remove_from_parent()
         # Check this after erasing instructions in case the block
         # loops into itself.
-        assert not any(self.uses)
+        assert all(use.is_removed for use in self.uses)
 
     def prepend(self, insn):
         assert isinstance(insn, Instruction)
@@ -1360,14 +1361,6 @@ class LandingPad(Terminator):
     def cleanup(self):
         return self.operands[0]
 
-    def erase(self):
-        self.remove_from_parent()
-        # we should erase all clauses as well
-        for block in set(self.operands):
-            block.uses.remove(self)
-            block.erase()
-        assert not any(self.uses)
-
     def clauses(self):
         return zip(self.operands[1:], self.types)
 
diff --git a/artiq/compiler/transforms/dead_code_eliminator.py b/artiq/compiler/transforms/dead_code_eliminator.py
index 608a46d55..f4862f2f9 100644
--- a/artiq/compiler/transforms/dead_code_eliminator.py
+++ b/artiq/compiler/transforms/dead_code_eliminator.py
@@ -15,13 +15,26 @@ class DeadCodeEliminator:
             self.process_function(func)
 
     def process_function(self, func):
-        modified = True
-        while modified:
-            modified = False
-            for block in list(func.basic_blocks):
-                if not any(block.predecessors()) and block != func.entry():
-                    self.remove_block(block)
-                    modified = True
+        # defer removing those blocks, so our use checks will ignore deleted blocks
+        preserve = [func.entry()]
+        work_list = [func.entry()]
+        while any(work_list):
+            block = work_list.pop()
+            for succ in block.successors():
+                if succ not in preserve:
+                    preserve.append(succ)
+                    work_list.append(succ)
+
+        to_be_removed = []
+        for block in func.basic_blocks:
+            if block not in preserve:
+                block.is_removed = True
+                to_be_removed.append(block)
+                for insn in block.instructions:
+                    insn.is_removed = True
+
+        for block in to_be_removed:
+            self.remove_block(block)
 
         modified = True
         while modified:
@@ -42,6 +55,8 @@ class DeadCodeEliminator:
     def remove_block(self, block):
         # block.uses are updated while iterating
         for use in set(block.uses):
+            if use.is_removed:
+                continue
             if isinstance(use, ir.Phi):
                 use.remove_incoming_block(block)
                 if not any(use.operands):
@@ -56,6 +71,8 @@ class DeadCodeEliminator:
 
     def remove_instruction(self, insn):
         for use in set(insn.uses):
+            if use.is_removed:
+                continue
             if isinstance(use, ir.Phi):
                 use.remove_incoming_value(insn)
                 if not any(use.operands):