1 files changed, 36 insertions, 0 deletions
diff --git a/tests/codegen-llvm/atomicptr.rs b/tests/codegen-llvm/atomicptr.rs
new file mode 100644
index 00000000000..4819af40ca2
--- /dev/null
+++ b/tests/codegen-llvm/atomicptr.rs
@@ -0,0 +1,36 @@
+// LLVM does not support some atomic RMW operations on pointers, so inside codegen we lower those
+// to integer atomics, surrounded by casts to and from integer type.
+// This test ensures that we do the round-trip correctly for AtomicPtr::fetch_byte_add, and also
+// ensures that we do not have such a round-trip for AtomicPtr::swap, because LLVM supports pointer
+// arguments to `atomicrmw xchg`.
+
+//@ compile-flags: -Copt-level=3 -Cno-prepopulate-passes
+#![crate_type = "lib"]
+#![feature(strict_provenance_atomic_ptr)]
+
+use std::ptr::without_provenance_mut;
+use std::sync::atomic::AtomicPtr;
+use std::sync::atomic::Ordering::Relaxed;
+
+// Portability hack so that we can say [[USIZE]] instead of i64/i32/i16 for usize.
+// CHECK: @helper([[USIZE:i[0-9]+]] noundef %_1)
+#[no_mangle]
+pub fn helper(_: usize) {}
+
+// CHECK-LABEL: @atomicptr_fetch_byte_add
+#[no_mangle]
+pub fn atomicptr_fetch_byte_add(a: &AtomicPtr<u8>, v: usize) -> *mut u8 {
+    // CHECK: %[[INTPTR:.*]] = ptrtoint ptr %{{.*}} to [[USIZE]]
+    // CHECK-NEXT: %[[RET:.*]] = atomicrmw add ptr %{{.*}}, [[USIZE]] %[[INTPTR]]
+    // CHECK-NEXT: inttoptr [[USIZE]] %[[RET]] to ptr
+    a.fetch_byte_add(v, Relaxed)
+}
+
+// CHECK-LABEL: @atomicptr_swap
+#[no_mangle]
+pub fn atomicptr_swap(a: &AtomicPtr<u8>, ptr: *mut u8) -> *mut u8 {
+    // CHECK-NOT: ptrtoint
+    // CHECK: atomicrmw xchg ptr %{{.*}}, ptr %{{.*}} monotonic
+    // CHECK-NOT: inttoptr
+    a.swap(ptr, Relaxed)
+}