Re: [3/4] [AArch64] SVE tests

[Richard Sandiford <richard dot sandiford at linaro dot org>]

James Greenhalgh <james.greenhalgh@arm.com> writes:
> On Fri, Nov 03, 2017 at 05:50:54PM +0000, Richard Sandiford wrote:
>> This patch adds gcc.target/aarch64 tests for SVE, and forces some
>> existing Advanced SIMD tests to use -march=armv8-a.
>
> I'm going to assume that these new testcases are broadly sensible, and not
> spend any significant time looking at them.
>
> I'm not completely happy forcing the architecture to Armv8-a - it would be
> useful for our testing coverage if users which have configured with other
> architecture variants had this test execute in those environments. That
> way we'd check we still do the right thing once we have an implicit
> -march=armv8.2-a .
>
> However, as we don't have a good way to make that happen (other than maybe
> only forcing the arch if we are in a configuration wired for SVE?) I'm
> happy with this patch as a compromise for now.

Would something like LLVM's -mattr be useful?  Then we could have
-mattr=+nosve without having to change the base architecture.

I suppose we'd need to be careful about how it interacts with -march
though, so it probably isn't GCC 8 material.  I'll try only forcing
the arch when we're compiling for SVE, like you say.

Not strictly related, but do you think it's OK to require binutils 2.28+
when testing GCC (rather than simply building it)?  When trying with an
older OS the other day, I realised that the SVE dg-do assemble tests
would fail for 2.27 and earlier.  We'd need something like:

  /* { dg-do assemble { aarch64_sve_asm } } */

if we wanted to support older binutils.

Thanks,
Richard