ir: Put function attribute detection under an opt-in flag.

Given it was a considerable performance hit under some workloads.

Closes #1465.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/headers/attribute_warn_unused_result_no_attribute_detection.hpp b/tests/headers/attribute_warn_unused_result_no_attribute_detection.hpp
new file mode 100644
index 00000000..21550307
--- /dev/null
+++ b/tests/headers/attribute_warn_unused_result_no_attribute_detection.hpp
@@ -0,0 +1,10 @@
+// bindgen-flags: --rust-target 1.27
+
+class Foo {
+public:
+    __attribute__((warn_unused_result))
+    int foo(int);
+};
+
+__attribute__((warn_unused_result))
+int foo(int);