RE: [PATCH 2/2]AArch64 Add support for neg on v1df

[Tamar Christina <Tamar.Christina@arm.com>]

> -----Original Message-----
> From: Richard Sandiford <richard.sandiford@arm.com>
> Sent: Friday, September 23, 2022 5:30 AM
> To: Tamar Christina <Tamar.Christina@arm.com>
> Cc: gcc-patches@gcc.gnu.org; nd <nd@arm.com>; Richard Earnshaw
> <Richard.Earnshaw@arm.com>; Marcus Shawcroft
> <Marcus.Shawcroft@arm.com>; Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> Subject: Re: [PATCH 2/2]AArch64 Add support for neg on v1df
> 
> Tamar Christina <tamar.christina@arm.com> writes:
> > Hi All,
> >
> > This adds support for using scalar fneg on the V1DF type.
> >
> > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> >
> > Ok for master?
> 
> Why just this one operation though?  Couldn't we extend iterators like
> GPF_F16 to include V1DF, avoiding the need for new patterns?
> 

Simply because it's the only one I know how to generate code for.
I can change GPF_F16 but I don't know under which circumstances we'd generate
a V1DF for the other operations.

So if it's ok to do so without full test coverage I'm happy to do so...

Tamar.

> Richard
> 
> >
> > Thanks,
> > Tamar
> >
> > gcc/ChangeLog:
> >
> > 	* config/aarch64/aarch64-simd.md (negv1df2): New.
> >
> > gcc/testsuite/ChangeLog:
> >
> > 	* gcc.target/aarch64/simd/addsub_2.c: New test.
> >
> > --- inline copy of patch --
> > diff --git a/gcc/config/aarch64/aarch64-simd.md
> > b/gcc/config/aarch64/aarch64-simd.md
> > index
> >
> f4152160084d6b6f34bd69f0ba6386c1ab50f77e..cf8c094bd4b76981cef2dd5dd7
> b8
> > e6be0d56101f 100644
> > --- a/gcc/config/aarch64/aarch64-simd.md
> > +++ b/gcc/config/aarch64/aarch64-simd.md
> > @@ -2713,6 +2713,14 @@ (define_insn "neg<mode>2"
> >    [(set_attr "type" "neon_fp_neg_<stype><q>")]
> >  )
> >
> > +(define_insn "negv1df2"
> > + [(set (match_operand:V1DF 0 "register_operand" "=w")
> > +       (neg:V1DF (match_operand:V1DF 1 "register_operand" "w")))]
> > +"TARGET_SIMD"
> > + "fneg\\t%d0, %d1"
> > +  [(set_attr "type" "neon_fp_neg_d")]
> > +)
> > +
> >  (define_insn "abs<mode>2"
> >   [(set (match_operand:VHSDF 0 "register_operand" "=w")
> >         (abs:VHSDF (match_operand:VHSDF 1 "register_operand" "w")))]
> > diff --git a/gcc/testsuite/gcc.target/aarch64/simd/addsub_2.c
> > b/gcc/testsuite/gcc.target/aarch64/simd/addsub_2.c
> > new file mode 100644
> > index
> >
> 0000000000000000000000000000000000000000..55a7365e897f8af509de953129
> e0
> > f516974f7ca8
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/aarch64/simd/addsub_2.c
> > @@ -0,0 +1,22 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-Ofast" } */
> > +/* { dg-final { check-function-bodies "**" "" "" { target { le } } }
> > +} */
> > +
> > +#pragma GCC target "+nosve"
> > +
> > +/*
> > +** f1:
> > +** ...
> > +**	fneg	d[0-9]+, d[0-9]+
> > +**	fadd	v[0-9]+.2s, v[0-9]+.2s, v[0-9]+.2s
> > +** ...
> > +*/
> > +void f1 (float *restrict a, float *restrict b, float *res, int n) {
> > +   for (int i = 0; i < 2; i+=2)
> > +    {
> > +      res[i+0] = a[i+0] + b[i+0];
> > +      res[i+1] = a[i+1] - b[i+1];
> > +    }
> > +}
> > +