[clang] [clang] Migrate DR tests to `static_assert` (PR #88611)

[via cfe-commits]

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@@ -5,6 +5,17 @@
 // RUN: %clang_cc1 -std=c++11 -verify=expected,cxx98-14,cxx98-17,cxx98-20,cxx11-14,since-cxx11 -triple %itanium_abi_triple %s -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++98 -verify=expected,cxx98-14,cxx98-17,cxx98-20,cxx98 -triple %itanium_abi_triple %s -fexceptions -fcxx-exceptions -pedantic-errors
 
+#if __cplusplus == 199711L
+#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
+// cxx98-error at -1 {{variadic macros are a C99 feature}}
+#endif
+
+#if __cplusplus == 199711L
+#define __enable_constant_folding(x) (__builtin_constant_p(x) ? (x) : (x))
+#else
+#define __enable_constant_folding
+#endif
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Sirraide wrote:

I don’t think we normally do that too often for tests, but this is the third file or so that I’ve seen so far that uses these macros, so I’d maybe suggest moving them into a header that the tests can include (especially considering you said you’re going to refactor more tests than just these) if that doesn’t cause any problems.

https://github.com/llvm/llvm-project/pull/88611