diff --git a/artiq/compiler/transforms/llvm_ir_generator.py b/artiq/compiler/transforms/llvm_ir_generator.py
index 003de3c1a..8ee010cc7 100644
--- a/artiq/compiler/transforms/llvm_ir_generator.py
+++ b/artiq/compiler/transforms/llvm_ir_generator.py
@@ -374,8 +374,6 @@ class LLVMIRGenerator:
             llty = ll.FunctionType(llvoid, [self.llty_of_type(builtins.TException())])
         elif name == "__artiq_reraise":
             llty = ll.FunctionType(llvoid, [])
-        elif name in "abort":
-            llty = ll.FunctionType(llvoid, [])
         elif name == "memcmp":
             llty = ll.FunctionType(lli32, [llptr, llptr, lli32])
         elif name == "rpc_send":
@@ -1143,8 +1141,6 @@ class LLVMIRGenerator:
     def process_Builtin(self, insn):
         if insn.op == "nop":
             return self.llbuilder.call(self.llbuiltin("llvm.donothing"), [])
-        if insn.op == "abort":
-            return self.llbuilder.call(self.llbuiltin("abort"), [])
         elif insn.op == "is_some":
             lloptarg = self.map(insn.operands[0])
             return self.llbuilder.extract_value(lloptarg, 0,
diff --git a/artiq/firmware/ksupport/api.rs b/artiq/firmware/ksupport/api.rs
index 89a6f638c..873dc6f71 100644
--- a/artiq/firmware/ksupport/api.rs
+++ b/artiq/firmware/ksupport/api.rs
@@ -63,7 +63,6 @@ static mut API: &'static [(&'static str, *const ())] = &[
     api!(__powidf2),
 
     /* libc */
-    api!(abort = ::abort),
     api!(memcmp, extern { fn memcmp(a: *const u8, b: *mut u8, size: usize); }),
 
     /* libm */