diff --git a/tests/mir-opt/README.md b/tests/mir-opt/README.md
index cd039bc7e05..39a7b5aea12 100644
--- a/tests/mir-opt/README.md
+++ b/tests/mir-opt/README.md
@@ -56,6 +56,8 @@ The LLVM FileCheck tool is used to verify the contents of output MIR against `CH
 present in the test file. This works on the runtime MIR, generated by `--emit=mir`, and not
 on the output of a individual passes.
 
+Use `// skip-filecheck` to prevent FileCheck from running.
+
 To check MIR for function `foo`, start with a `// CHECK-LABEL fn foo(` directive.
 
 `{{regex}}` syntax allows to match `regex`.