[PATCH] testsuite: Fix sse2-andnpd-1.c and sse-andnps-1.c testscases on powerpc

[Segher Boessenkool]

Hi!

On Sat, Jan 23, 2021 at 09:41:23AM +0100, Jakub Jelinek wrote:
> On Fri, Jan 22, 2021 at 06:56:37PM -0600, Segher Boessenkool wrote:
> > So what is the actual error here?  This whole union stuff is because we
> > *do* want proper aliasing, afaics.
> 
> The reading through union is not where the problem is, the problem
> was in the reading through VALUE_TYPE, because the testcase does:
>   int e[4];
> ...
>   e[0] = (~source1[0]) & source2[0];
>   e[1] = (~source1[1]) & source2[1];
>   e[2] = (~source1[2]) & source2[2];
>   e[3] = (~source1[3]) & source2[3];
> 
>   if (check_union128 (u, (float *)e))

Right, that should use such a union as well, or similar.  Most of the
other similar mechanics in the testcase are because we *do* want proper
alising rules, so it would be a shame to throw it all away now.

> So check_union128 reads through VALUE_TYPE of float, but the variable
> has dynamic type int[4].  Even making a e union of int[4] and float[4]
> and passing address of the float field in it wouldn't be correct,
> but e.g. having another variable with float[4] type and memcpying
> e into it would work too.  So:
>   int e[4];
>   float f[4];
> ...
>   e[0] = (~source1[0]) & source2[0];
>   e[1] = (~source1[1]) & source2[1];
>   e[2] = (~source1[2]) & source2[2];
>   e[3] = (~source1[3]) & source2[3];
>   memcpy (f, e, sizeof (e));
> 
>   if (check_union128 (u, f))

That, or have the function take a pointer-to-union, or make "e" a union
itself.  All should work.

> The reason I chose the "no-strict-aliasing" attribute (and already
> committed based on Richi's ack) was consistency with the i386
> testcase.  I can change both.

Yes please.  Thanks!


Segher