Re: [PATCH] RISC-V: Use .p2align for code-alignment

[Philipp Tomsich <philipp.tomsich@vrull.eu>]

On Tue, 15 Nov 2022 at 22:14, Philipp Tomsich <philipp.tomsich@vrull.eu> wrote:
>
> Jeff,
>
> On Tue, 15 Nov 2022 at 17:37, Jeff Law <jeffreyalaw@gmail.com> wrote:
> >
> >
> > On 11/13/22 13:41, Philipp Tomsich wrote:
> >
> > RISC-V's .p2align (currently) ignores the max-skip argument.  As we
> > have experimental patches underway to address this in a
> > backwards-compatible manner, let's prepare GCC for the day when
> > binutils gets updated.
> >
> > gcc/ChangeLog:
> >
> > * config/riscv/riscv.h (ASM_OUTPUT_MAX_SKIP_ALIGN): Implement.
> >
> >
> > What are the implications if we start using p2align immediately when the current (broken?) state of the assembler?  I'm pretty sure configure is already turning on HAVE_GAS_SKIP_P2ALIGN.  From a native risc-v build:
> >
> >
> > auto-host.h:#define HAVE_GAS_MAX_SKIP_P2ALIGN 1
>
> This is your tree, which has the (partial fix — i.e., the best we can
> do without breaking backward compatibility) for .p2align.
> When building against upstream binutils, this should not be defined.

After rereading the generated configure-script, I've changed my mind
The check the does nothing to ensure that the max-skip is actually
honored and only tests whether it is accepted.

Having the max-skip silently ignored may still be the lesser evil.

Philipp.