1; RUN: llc < %s -march=x86-64 | FileCheck %s
2
3@var = external global i64		; <i64*> [#uses=1]
4
5define i32 @main() nounwind {
6entry:
7; CHECK: main:
8; CHECK: lock
9; CHECK: decq
10	atomicrmw sub i64* @var, i64 1 monotonic
11	unreachable
12}
13