Re: [PATCH] report message for operator %a on unaddressible exp

[Segher Boessenkool <segher@kernel.crashing.org>]

Hi!

On Thu, May 16, 2024 at 02:56:49PM +0800, Jiufu Guo wrote:
> Jiufu Guo <guojiufu@linux.ibm.com> writes:
> > Segher Boessenkool <segher@kernel.crashing.org> writes:
> >> On Tue, May 14, 2024 at 05:53:56PM +0800, Jiufu Guo wrote:
> >>> Thanks so much for your great review!
> >>> Reference other messages, I'm wondering "invalid %%a value" may be
> >>> acceptable, or "invalid %%a address expression in TOC" maybe better.
> >>
> >> "%%a requires a memory operand"?  Maybe even print out the actual
> >> operand given, too.
> >
> > Thanks! I updated the code using:
> > "%%a requires a memory reference operand", since the actual operand
> > is treated as the address.
> 
> I suspect one thing here: if "%%a requires memory" is accurate vs.
> "%%a requires a memory reference".
> 
> Reference the words from doc:
> https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Generic-Operand-Modifiers
> a: Substitute a memory reference, with the actual operand treated as the
> address.
> 
> And for below code:
> '("#%a0" : :"m"(x))' is not accepted.

Yeah, it always confuses me.  Sorry.  The operand is the actual address.

> While '("#%a0" : :"r"(&x))' is ok.
> 
> So, it may be more accurate that: "%%a" as requirement of address of
> memory.

That sounds good yes.


Segher