[Mesa-dev] [PATCH] util: no-op __builtin_types_compatible_p() for non-GCC compilers

[Brian Paul]

On 03/29/2019 12:58 PM, Ian Romanick wrote:
> On 3/29/19 9:57 AM, Brian Paul wrote:
>> __builtin_types_compatible_p() is GCC-specific and breaks the
>> MSVC build.
>>
>> This intrinsic has been in u_vector_foreach() for a long time, but
>> that macro has only recently been used in code
>> (nir/nir_opt_comparison_pre.c) that's built with MSVC.
>>
>> Fixes: 2cf59861a ("nir: Add partial redundancy elimination for compares")
>> ---
>>   src/util/u_vector.h | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/src/util/u_vector.h b/src/util/u_vector.h
>> index cd8a95d..6807748 100644
>> --- a/src/util/u_vector.h
>> +++ b/src/util/u_vector.h
>> @@ -80,6 +80,10 @@ u_vector_finish(struct u_vector *queue)
>>      free(queue->data);
>>   }
>>   
>> +#ifndef __GNUC__
>> +#define __builtin_types_compatible_p(x) 1
>> +#endif
>> +
>>   #define u_vector_foreach(elem, queue)                                  \
>>      STATIC_ASSERT(__builtin_types_compatible_p(__typeof__(queue), struct u_vector *)); \
> 
> The way this is GCC builtin is used here, this should be fine.  However,
> in case it's begin used elsewhere, we should #undef it afterwards.


That doesn't seem to work.  When u_vector_foreach() is instantiated 
later, __builtin_types_compatible_p is undefined and we error out.

-Brian


   I'd
> hate to mask some other kind of bug that may be introduced later.
> 
>>      for (uint32_t __u_vector_offset = (queue)->tail;                                \
>>
>