Doing all-ABIs compile testing produces a compiler warning in
stdlib/bug-getcontext.c on nios2 and tilepro (with GCC 5 branch):
bug-getcontext.c: In function 'do_test':
bug-getcontext.c:53:6: error: 'except_mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
if (mask != except_mask)
^
This warning appears nonsensical; except_mask is initialized where
it's declared. I think what must be happening here is that the
compiler is confused by the returns-twice nature of getcontext: if
there were a call to setcontext, local variables could indeed have
lost their values on the second return from getcontext. This patch
duly uses the DIAG_* macros to disable the warning here.
Tested for nios2 and tilepro (compilation only; after this patch all
the tests compile, though there are other failures) and x86_64 (full
testsuite run).
* stdlib/bug-getcontext.c: Include <libc-internal.h>.
(do_test): Disable -Wmaybe-uninitialized around uses of
except_mask.
For some tests, just claim that fetestexcept() always returns true,
so the rest of the test can be compiled.
For libm-test, provide known bogus values for unsupported rounding
modes, so fesetround() will return failure.
Elsewhere, just add some #ifdefs to avoid code that uses particular
FP exceptions if the exceptions aren't supported.
