Am 19.06.2016 um 11:41 schrieb Peter Maydell:
> On 19 June 2016 at 06:53, Stefan Weil <s...@weilnetz.de> wrote:
>> Am 19.06.2016 um 00:05 schrieb Peter Maydell:
>>> From: Peter Maydell <peter.mayd...@linaro.org>
>>>
>>> The AVX2 optimization test assumes that the object format
>>> is ELF and the system has the readelf utility. If this isn't
>>> true then configure might fail or emit a warning (since in
>>> a pipe "foo | bar >/dev/null 2>&1" does not redirect the
>>> stderr of foo, only of bar). Adjust the check so that if
>>> we don't have readelf or don't have an ELF object then we
>>> just don't enable the AVX2 optimization.
>>>
>>> Reported-by: Stefan Weil <s...@weilnetz.de>
>>> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
>>> ---
>>> configure | 6 ++++--
>>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/configure b/configure
>>> index 7beefcd..30bca55 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -1792,8 +1792,10 @@ int foo(void *a) __attribute__((ifunc("bar_ifunc")));
>>> int main(int argc, char *argv[]) { return foo(argv[0]);}
>>> EOF
>>> if compile_object "" ; then
>>> - if readelf --syms $TMPO |grep "IFUNC.*foo" >/dev/null 2>&1; then
>>> - avx2_opt="yes"
>>> + if has readelf; then
>>> + if readelf --syms $TMPO 2>/dev/null |grep -q "IFUNC.*foo"; then
>>> + avx2_opt="yes"
>>> + fi
>>> fi
>>> fi
>>>
>>>
>>
>> You could check "has readelf" earlier and avoid the compile test
>> if there is no readelf (saves a little time).
>
> I guess so, though there's not much in it.
>
>> The final I/O redirection is still needed (otherwise Linux users will
>> see the grep output).
>
> I added -q which should suppress that, no ?
>
> thanks
> -- PMM
>
Sorry, I missed that detail.
Reviewed-by: Stefan Weil <s...@weilnetz.de>
