Re: [Qemu-devel] [PATCH] include/fpu/softfloat: Fix compilation with Clang on s390x

["Alex Bennée" <alex.bennee@linaro.org>]

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 1/14/19 1:12 PM, Thomas Huth wrote:
>> Clang v7.0.1 does not like the __int128 variable type for inline
>> assembly on s390x:
>>
>> In file included from fpu/softfloat.c:97:
>> include/fpu/softfloat-macros.h:647:9: error: inline asm error:
>>  This value type register class is not natively supported!
>>     asm("dlgr %0, %1" : "+r"(n) : "r"(d));
>>         ^
>>
>> Disable this code part there now when compiling with Clang, so that
>> the generic code gets used instead.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>  include/fpu/softfloat-macros.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/fpu/softfloat-macros.h b/include/fpu/softfloat-macros.h
>> index b1d772e..bd5b641 100644
>> --- a/include/fpu/softfloat-macros.h
>> +++ b/include/fpu/softfloat-macros.h
>> @@ -641,7 +641,7 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t n1,
>>      uint64_t q;
>>      asm("divq %4" : "=a"(q), "=d"(*r) : "0"(n0), "1"(n1), "rm"(d));
>>      return q;
>> -#elif defined(__s390x__)
>> +#elif defined(__s390x__) && !defined(__clang__)
>
> Can we rather check if __int128 is natively supported? So this part get
> compiled once Clang do support it, else we'll never use it...

We already define CONFIG_INT128 so you could just use that.

Thomas does the s390 clang leave CONFIG_INT128=y in config-host.mak?

>
>>      /* Need to use a TImode type to get an even register pair for DLGR.  */
>>      unsigned __int128 n = (unsigned __int128)n1 << 64 | n0;
>>      asm("dlgr %0, %1" : "+r"(n) : "r"(d));
>>


--
Alex Bennée