Re: [PING 6][PATCH v3] rs6000/p8swap: Fix incorrect lane extraction by vec_extract() [PR106770]

Hi Mike,

On 20/05/26 11:53 AM, Michael Meissner wrote:
> Note, the tests are rather tricky, and I believe they will not work
> correctly if you configure the compiler to default to power9, power10,
> or power11 code.
> 
> The test has the guard condition:
> 
> /* { dg-require-effective-target powerpc_p8vector_ok } */
> /* { dg-options "-mdejagnu-cpu=power8 -O2 " } */
> 
> What -mdejagnu-cpu=power8 does is tell the test compiler to use
> -mcpu=power8 if the default target is not at the power8 level.  If you
> configure the compiler to default to power9, power10, or power11, using
> -mdejagnu-cpu=power8 will not change the default.

I built a compiler with --with-cpu=power10. And with this compiler if I
run a test that specifies -mdejagnu-cpu=power8, this option is honoured and power8
assembly is generated.
Am I missing something?

-Surya

> 
> Given that the byte swapping vector instructions were added in power9,
> if the default target is power9 or high, the p8swap support is turned
> off.
> 
> You could change the guard condition to:
> 
> /* { dg-require-effective-target powerpc_p8vector_ok } */
> /* { dg-options "-mdejagnu-cpu=power8 -O2 " } */
> 
> Or add the following line (with an explanation) in the source before
> the function in the test:
> 
> #pragma GCC target ("cpu=power8")
>