Re: [PATCH][X86] Fix rounding pattern similar to PR73350

["H.J. Lu" <hjl.tools@gmail.com>]

On Mon, Jun 12, 2017 at 9:06 AM, Koval, Julia <julia.koval@intel.com> wrote:
> I would like to, but as far as I know the only testcase possible is below, and as far as I know there is no possibility to use dg-error for runtime exceptions(Sorry, if I'm wrong). There are only 2 versions of the flag exception or no exception and the error is, when they are combined in CSE.

Can you use

if (wrong)
  abort ();

in testcase?

>> -----Original Message-----
>> From: H.J. Lu [mailto:hjl.tools@gmail.com]
>> Sent: Monday, June 12, 2017 3:43 PM
>> To: Koval, Julia <julia.koval@intel.com>
>> Cc: GCC Patches <gcc-patches@gcc.gnu.org>; Uros Bizjak
>> <ubizjak@gmail.com>; Kirill Yukhin <kirill.yukhin@gmail.com>
>> Subject: Re: [PATCH][X86] Fix rounding pattern similar to PR73350
>>
>> On Mon, Jun 12, 2017 at 6:21 AM, Koval, Julia <julia.koval@intel.com> wrote:
>> > This is the same issue as PR73350 and PR80862 for disabling FP exceptions.
>> >
>> > gcc -O0 -mavx512f -mavx512er returns exception
>> > gcc -O2 -mavx512f -mavx512er returns nan
>> >
>> > For this code:
>> >
>> > #include <stdio.h>
>> > #include <math.h>
>> > #include <x86intrin.h>
>> > #include <limits.h>
>> > #include <float.h>
>> >
>> > int main(int argc, char *argv[]) {
>> >     __m512 a = _mm512_set1_ps((float) -1);
>> >     __m512 b = _mm512_set1_ps((float) -1);
>> >     _mm_setcsr( _MM_MASK_MASK &~
>> >
>> (_MM_MASK_OVERFLOW|_MM_MASK_INVALID|_MM_MASK_DIV_ZERO) );
>> >     __m512 result1 = _mm512_rsqrt28_round_ps(a, _MM_FROUND_NO_EXC );
>> >     printf("%d %d\n", _MM_FROUND_CUR_DIRECTION,
>> _MM_FROUND_NO_EXC);
>> >     __m512 result2 = _mm512_rsqrt28_round_ps(a,
>> _MM_FROUND_CUR_DIRECTION);
>> >
>> >     printf("%g\n", result1[0] - result2[0]);
>> >
>> >     return 0;
>> > }
>> >
>> > This patch fixes the issue.
>> >
>> > gcc/
>> >         * config/i386/i386.c: Fix rounding expand for new pattern
>> >         * config/i386/subst.md: Fix pattern (parallel -> unspec)
>> >
>> > Ok for trunk?
>> >
>>
>> Please include the testcase.
>>
>> Thanks.
>>
>> --
>> H.J.



-- 
H.J.