Re: [PATCH v6] coresight: etm4x: avoid build failure with unrolled loops

[Suzuki K Poulose]

On 10/07/2022 20:13, Arnd Bergmann wrote:
> On Sat, Jul 9, 2022 at 1:15 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote:
>
> >          ({                                                                      \
> >                  u64 __val;                                                      \
> >                                                                                  \
> > -               if (__builtin_constant_p((offset)))                             \
> > +               if (__is_constexpr((offset)))                                   \
> >                          __val = read_etm4x_sysreg_const_offset((offset));       \
> >                  else                                                            \
> >                          __val = etm4x_sysreg_read((offset), true, (_64bit));    \
>
> This is clearly better than the current version using
> __builtin_constant_p(), but
> I don't think it's safe in all cases, since there are expressions that
> are constant
> expressions to the compiler but are not valid input to the assembler.
>
> I would prefer to see this fixed differently, but doing this one first is also
> fine with me:
>
> Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
>
>          Arnd


Thanks, I have queued this.

Suzuki