Re: [PATCH] PPC64: First in the series of patches implementing POWER8 vector math.

[Joseph Myers <joseph at codesourcery dot com>]

If you have a copyright assignment / employer disclaimer on file at the 
FSF, could you give details of the names involved?

>         * sysdeps/powerpc/powerpc64/multiarch/test-double-vlen2.c: New file.

Why?  x86_64 doesn't have this.

> +#if defined _ARCH_PPC64 && defined __FAST_MATH__

Is _ARCH_PPC64 correct here - what's the status of support (in the GNU 
toolchain, Linux kernel, etc.) for -mpowerpc64 with the 32-bit ABI (which 
also defines _ARCH_PPC64)?

> diff --git a/sysdeps/powerpc/powerpc64/fpu/Versions b/sysdeps/powerpc/powerpc64/fpu/Versions
> new file mode 100644
> index 0000000000..9da7f92ffe
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/fpu/Versions
> @@ -0,0 +1,6 @@
> +libmvec {
> +  GLIBC_2.30 {
> +    _ZGVbN2v_cos;
> +  }
> +}
> +

You can't push commits that add blank lines at end of files; the 
repository blocks such pushes.

> diff --git a/sysdeps/powerpc/powerpc64/fpu/multiarch/math-tests-arch.h b/sysdeps/powerpc/powerpc64/fpu/multiarch/math-tests-arch.h
> new file mode 100644
> index 0000000000..e79b98480b
> --- /dev/null
> +++ b/sysdeps/powerpc/powerpc64/fpu/multiarch/math-tests-arch.h
> @@ -0,0 +1,19 @@
> +/*
> +   Copyright (C) 2019 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <sysdeps/generic/math-tests-arch.h>

This file is useless (the only point of a sysdeps file that just includes 
the generic version would be to override a file in another sysdeps 
directory that would otherwise be used).

> +vector double _ZGVbN2v_cos_vsx (vector double x)
> +{
> +
> +/*
> +   ARGUMENT RANGE REDUCTION:
> +   Add Pi/2 to argument: X' = X+Pi/2
> + */
> +    vector double x_prime = (vector double) *dHalfPI + x;

Code formatting needs fixing to follow the GNU Coding Standards, here and 
elsewhere in the patch.

> +#include <altivec.h>
> +
> +vector unsigned long long dHalfPI_t   =
> +{0x3ff921fb54442d18,0x3ff921fb54442d18};

There are namespace problems here.  All external constants should have 
names in the implementation namespace, meaning two leading underscores.  
They should also be const; don't add new writable global variables.  In 
addition, use vector double and hex floats, rather than writing out the 
integer representation.  In addition, each constant should have a comment 
explaining its semantics, sufficiently precisely that someone could 
recompute the value and verify its correctness.

-- 
Joseph S. Myers
joseph@codesourcery.com