On Thu, Nov 21, 2013 at 4:39 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
> On Thu, 21 Nov 2013, Cong Hou wrote:
>
>> While I added the new define_insn_and_split for vec_merge, a bug is
>> exposed: in config/i386/sse.md, [ define_expand "xop_vmfrcz<mode>2" ]
>> only takes one input, but the corresponding builtin functions have two
>> inputs, which are shown in i386.c:
>>
>> { OPTION_MASK_ISA_XOP, CODE_FOR_xop_vmfrczv4sf2,
>> "__builtin_ia32_vfrczss", IX86_BUILTIN_VFRCZSS, UNKNOWN,
>> (int)MULTI_ARG_2_SF },
>> { OPTION_MASK_ISA_XOP, CODE_FOR_xop_vmfrczv2df2,
>> "__builtin_ia32_vfrczsd", IX86_BUILTIN_VFRCZSD, UNKNOWN,
>> (int)MULTI_ARG_2_DF },
>>
>> In consequence, the ix86_expand_multi_arg_builtin() function tries to
>> check two args but based on the define_expand of xop_vmfrcz<mode>2,
>> the content of insn_data[CODE_FOR_xop_vmfrczv4sf2].operand[2] may be
>> incorrect (because it only needs one input).
>>
>> The patch below fixed this issue.
>>
>> Bootstrapped and tested on ax x86-64 machine. Note that this patch
>> should be applied before the one I sent earlier (sorry for sending
>> them in wrong order).
>
>
> This is PR 56788. Your patch seems strange to me and I don't think it
> fixes the real issue, but I'll let more knowledgeable people answer.
Thank you for pointing out the bug report. This patch is not intended
to fix PR56788. For your function:
#include <x86intrin.h>
__m128d f(__m128d x, __m128d y){
return _mm_frcz_sd(x,y);
}
Note that the second parameter is ignored intentionally, but the
prototype of this function contains two parameters. My fix is
explicitly telling GCC that the optab xop_vmfrczv4sf3 should have
three operands instead of two, to let it have the correct information
in insn_data[CODE_FOR_xop_vmfrczv4sf3].operand[2] which is used to
match the type of the second parameter in the builtin function in
ix86_expand_multi_arg_builtin().
thanks,
Cong
>
> --
> Marc Glisse
