Ignore the unchecked-shifts codegen test in debug-assertions builds
diff --git a/src/test/codegen/unchecked_shifts.rs b/src/test/codegen/unchecked_shifts.rs
index d67d3a8..60d0cb0 100644
--- a/src/test/codegen/unchecked_shifts.rs
+++ b/src/test/codegen/unchecked_shifts.rs
@@ -1,5 +1,6 @@
// compile-flags: -O
// min-llvm-version: 15.0 (LLVM 13 in CI does this differently from submodule LLVM)
+// ignore-debug (because unchecked is checked in debug)
#![crate_type = "lib"]
#![feature(unchecked_math)]
