[llvm] [compiler-rt] [test][msan] Precommit tests for vararg improvements (PR #72612)

[Thurston Dang via llvm-commits]

================
@@ -0,0 +1,256 @@
+// Check that shadow of retrived value from va_list matches the shadow of passed value.
+
+// Without -fno-sanitize-memory-param-retval we can't even pass poisoned values.
+// RUN: %clangxx_msan -fno-sanitize-memory-param-retval -fsanitize-memory-track-origins=0 -O3 %s -o %t
+
+// Nothing works yet.
+// XFAIL: *
+
+#include <sanitizer/msan_interface.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define DEBUG_TEST 0
----------------
thurstond wrote:

Maybe guard it with ifdef, to allow overriding it as a compile flag?

https://github.com/llvm/llvm-project/pull/72612