Add -fno-devirtualize when using GCC 12 (GH #1134, GH #1141, PR #1147)

This is not a fix since it only treats the symptom of GCC removing live code. We do not know why GCC is doing it.

1 files changed, 19 insertions, 0 deletions

diff --git a/TestPrograms/test_nodevirtualize.cpp b/TestPrograms/test_nodevirtualize.cpp
new file mode 100644
index 00000000..ad4489a4
--- /dev/null
+++ b/TestPrograms/test_nodevirtualize.cpp
@@ -0,0 +1,19 @@
+#include <string>

+

+// https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html

+#define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)

+

+int main(int argc, char* argv[])

+{

+    // GCC 12 is removing live code. We don't know why.

+    // https://github.com/weidai11/cryptopp/issues/1134 and

+    // https://github.com/weidai11/cryptopp/issues/1141

+#if defined(__linux__) && (GCC_VERSION >= 120000)

+    // On successful compile -fno-devirtualize will be used

+    // to work around the problem.

+    ;;

+#else

+    int x[-1];

+#endif

+    return 0;

+}