diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 5d9c1a876f0cb..111604ce1ffc7 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -580,10 +580,10 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
             PassMode::Direct(_) | PassMode::Pair(..) => {
                 let op = self.codegen_consume(bx, mir::Place::return_place().as_ref());
-                if let Ref(place_val) = op.val {
-                    bx.load_from_place(bx.backend_type(op.layout), place_val)
-                } else {
-                    op.immediate_or_packed_pair(bx)
+                match op.val {
+                    Ref(place_val) => bx.load_from_place(bx.backend_type(op.layout), place_val),
+                    Uninit => bx.cx().const_undef(bx.cx().immediate_backend_type(op.layout)),
+                    _ => op.immediate_or_packed_pair(bx),
                 }
             }
 
diff --git a/tests/codegen-llvm/uninit-return-value.rs b/tests/codegen-llvm/uninit-return-value.rs
new file mode 100644
index 0000000000000..3a4debb1d4f78
--- /dev/null
+++ b/tests/codegen-llvm/uninit-return-value.rs
@@ -0,0 +1,13 @@
+// Regression test for https://github.com/rust-lang/rust/issues/159815
+
+#![crate_type = "lib"]
+
+use std::mem::MaybeUninit;
+
+// CHECK-LABEL: @f
+#[no_mangle]
+pub fn f() -> MaybeUninit<*const ()> {
+    // CHECK: start:
+    // CHECK-NEXT: ret ptr undef
+    const { MaybeUninit::uninit() }
+}