diff --git a/src/codegen.cpp b/src/codegen.cpp
index 69c8ea00f1586..377700d5530e2 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -4718,6 +4718,8 @@ static std::unique_ptr<Module> emit_function(jl_lambda_info_t *lam, jl_llvm_func
         }
     }
 
+    builder.ClearInsertionPoint();
+
     // step 13, Apply LLVM level inlining
     for(std::vector<CallInst*>::iterator it = ctx.to_inline.begin(); it != ctx.to_inline.end(); ++it) {
         Function *inlinef = (*it)->getCalledFunction();
diff --git a/test/core.jl b/test/core.jl
index ee4605ff60704..b3dd90d9bba49 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -4469,3 +4469,10 @@ let
     k(x) = (k = x; k)
     @test k(1) == 1
 end
+
+# PR #18054: compilation of cfunction leaves IRBuilder in bad state,
+#            causing heap-use-after-free when compiling f18054
+function f18054()
+    return Cint(0)
+end
+cfunction(f18054, Cint, ())