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


Hi,

Any more suggestions or comments on the patch ?

Thank you
~Umesh

On Tue, Jul 24, 2018, 2:08 PM Umesh Kalappa <umesh.kalappa0@gmail.com>
wrote:

> Thank you All for the suggestions  and we tried runing the GCC
> testsuite and found that no regression with the fix and also ran the
> our regressions base for conformance with no regress.
>
> Is ok for commit with below  Changelog ?
> +++ libgcc/ChangeLog    (working copy)
> @@ -1,3 +1,9 @@
> +2018-07-18  Umesh Kalappa <umesh.kalappa0@gmail.com>
> +
> +       PR libgcc/86512
> +       * config/arm/ieee754-df.S :Don't normalise the denormal result.
> +       * config/arm/ieee754-sf.S:Likewise.
> +
> +
> +++ gcc/testsuite/ChangeLog     (working copy)
> @@ -1,3 +1,8 @@
> +2018-07-18  Umesh Kalappa <umesh.kalappa0@gmail.com>
> +
> +       PR libgcc/86512
> +       * gcc.target/arm/pr86512.c :New test.
> +
>
> On Mon, Jul 23, 2018 at 5:24 PM, Wilco Dijkstra <Wilco.Dijkstra@arm.com>
> wrote:
> > Umesh Kalappa wrote:
> >
> >> We tested on the SP and yes the problem persist on the SP too and
> >> attached patch will fix the both SP and DP issues for the  denormal
> >> resultant.
> >
> > The patch now looks correct to me (but I can't approve).
> >
> >> We bootstrapped the compiler ,look ok to us with minimal testing ,
> >>
> >> Any floating point test-suite to test for the attached patch ? any
> >> recommendations or inputs  ?
> >
> > Running the GCC regression tests would be required since a bootstrap
> isn't
> > useful for this kind of change. Assuming you use Linux, building and
> running
> > GLIBC with the changed GCC would give additional test coverage as it
> tests
> > all the math library functions.
> >
> > I don't know of any IEEE conformance testsuites in the GNU world, which
> is
> > why I'm suggesting running some targeted and randomized tests. You could
> > use the generic soft-float code in libgcc/soft-fp/adddf3.c to compare
> the outputs.
> >
> >
> >>>> Index: libgcc/config/arm/ieee754-df.S
> >>>> ===================================================================
> >>>> --- libgcc/config/arm/ieee754-df.S   (revision 262850)
> >>>> +++ libgcc/config/arm/ieee754-df.S   (working copy)
> >>>> @@ -203,6 +203,7 @@
> >>>>  #endif
> >>>>
> >>>>      @ Determine how to normalize the result.
> >>>> +    @ if result is denormal i.e (exp)=0,then don't normalise the
> result,
> >
> > Use a standard sentence here, eg. like:
> >
> > If exp is zero and the mantissa unnormalized, return a denormal.
> >
> > Wilco
> >
>


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