Fix vect_float markup for a couple of tests (PR 83888)

[Richard Sandiford]

Richard Biener <richard.guenther@gmail.com> writes:
> On Mon, Jan 22, 2018 at 6:55 PM, Richard Sandiford
> <richard.sandiford@linaro.org> wrote:
>> vect_float is true for arm*-*-* targets, but the support is only
>> available when -funsafe-math-optimizations is on.  This caused
>> failures in two tests that disable fast-math.
>>
>> The easiest fix seemed to be to add a new target selector for
>> "vect_float without special options".
>>
>> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
>> OK to install?
>
> Ok - so arm float vectors are not IEEE compliant?

Not for subnormals apparently:

; Note that NEON operations don't support the full IEEE 754 standard: in
; particular, denormal values are flushed to zero.  This means that GCC cannot
; use those instructions for autovectorization, etc. unless
; -funsafe-math-optimizations is in effect (in which case flush-to-zero
; behavior is permissible).

Thanks,
Richard