Some goto-cc regression tests fail when native compiler is clang-6.0

[smowton]

Failing tests:

regression/ansi-c/MMX2:

/usr/lib/llvm-6.0/lib/clang/6.0.0/include/emmintrin.h: In function '_mm_avg_epu8':
/usr/lib/llvm-6.0/lib/clang/6.0.0/include/emmintrin.h:2280:1: error: operator `+' not defined for types `unsigned short int __attribute__((vector_size (16l*sizeof(unsigned short int))))' and `signed int'

regression/ansi-c/gcc_builtins4: STATIC_ASSERT(__builtin_classify_type((_Bool)0)==4) fails. Someone expected Clang would classify _Bool as a logical rather than an integer type, which may be true for some Clangs, but evidently not 6.0, at least not 6.0 + glibc-2.27 (if libc is even responsible for defining _Bool). Need to check which compilers classify it which way.

regression/cbmc/ts18661_typedefs: conflicting type modifiers when trying to overwrite a builtin type (_Float128) with a typedef. This is expected, as cbmc doesn't use gcc_versiont yet to check what the native compiler defines -- when it does, it should mimic Clang's support or otherwise for _Float128 et al.

[smowton]

I also repeated these tests with clang-3.9, the oldest Clang readily available to me, and found the MMX2 test does not fail, but the gcc_builtins4 and ts18661 tests fail in the same way.

[kroening]

BTW, is this now fixed?

[smowton]

No, all three failures are as described still