[Patch-86512]: Subnormal float support in armv7(with -msoft-float) for intrinsics

[Umesh Kalappa]

Hi Nagy/Ramana,

Please help us to review the attached patch and do let me know your comments .

No regress in the  gcc.target  suite for arm target.

Thank you
~Umesh

On Tue, Jul 17, 2018 at 4:01 PM, Umesh Kalappa <umesh.kalappa0@gmail.com> wrote:
> Will do, thanks.
> Thanks
>
> On Tue, Jul 17, 2018, 3:24 PM Ramana Radhakrishnan
> <ramana.gcc@googlemail.com> wrote:
>>
>> On Tue, Jul 17, 2018 at 10:41 AM, Umesh Kalappa
>> <umesh.kalappa0@gmail.com> wrote:
>> > Hi Nagy,
>> >
>> > Please  help us with your comments on the attached patch for the issue
>> > (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86512)
>> >
>> > Thank you and waiting for your inputs on the same.
>>
>>
>> Patches should be sent to gcc-patches@gcc.gnu.org with a clear
>> description of what the patch hopes to
>> achieve and why this is correct, how was it tested and if a regression
>> test needs to be added - add one please.
>> Please read https://gcc.gnu.org/contribute.html before sending a patch.
>>
>> This is the wrong list to send patches to.
>>
>> regards
>> Ramana
>> > ~Umesh
>> >
>> > On Fri, Jul 13, 2018 at 1:22 PM, Umesh Kalappa
>> > <umesh.kalappa0@gmail.com> wrote:
>> >> Thank you and issue  raised at
>> >> gcc-patches@gcc.gnu.org
>> >>
>> >> ~Umesh
>> >>
>> >> On Thu, Jul 12, 2018 at 9:33 PM, Szabolcs Nagy <szabolcs.nagy@arm.com>
>> >> wrote:
>> >>> On 12/07/18 16:20, Umesh Kalappa wrote:
>> >>>>
>> >>>> Hi everyone,
>> >>>>
>> >>>> we have our source base ,that was compiled for armv7 on gcc8.1 with
>> >>>> soft-float and for following input
>> >>>>
>> >>>> a=0x0010000000000000
>> >>>> b=0x0000000000000001
>> >>>>
>> >>>>   result = a - b ;
>> >>>>
>> >>>> we are getting the result as "0x000ffffffffffffe" and with
>> >>>> -mhard-float (disabled the flush to zero mode ) we are getting the
>> >>>> result as ""0x000fffffffffffff" as expected.
>> >>>>
>> >>>
>> >>> please submit it as a bug report to bugzilla
>> >>>
>> >>>
>> >>>> while debugging the soft-float code,we see that ,the compiler calls
>> >>>> the intrinsic "__aeabi_dsub" with arm calling conventions i.e passing
>> >>>> "a" in r0 and r1 registers and respectively for "b".
>> >>>>
>> >>>> we are investigating the routine "__aeabi_dsub" that comes from
>> >>>> libgcc
>> >>>> for incorrect result  and meanwhile we would like to know that
>> >>>>
>> >>>> a)do libgcc routines/intrinsic for float operations support or
>> >>>> consider the subnormal values ? ,if so how we can enable the same.
>> >>>>
>> >>>> Thank you
>> >>>> ~Umesh
>> >>>>
>> >>>
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