Re: [PATCH] rs6000/test: Fix bswap64-4.c with has_arch_ppc64 [PR106680]

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

On Fri, Sep 02, 2022 at 08:50:52AM +0800, Kewen.Lin wrote:
> on 2022/9/1 22:57, Segher Boessenkool wrote:
> > These two are independent, but apparently we have a bug here, which will
> > make what you did malfunction in some cases -- the test will not run for
> > ilp32 if you have RUNTESTFLAGS {-m32,-m64}.
> 
> Yeah, because of the bug (or call it surprised behavior),

No, I call it a bug.  Because that is what it is!

> the test case can
> fail for some dejaGnu version like 1.5.1 (how it places the dg-options matters).

Yes, but that is only one way to expose the problem.

The bug just should be fixed.

> But to be clarified, the order of 
> 
>   /* { dg-options "-O2 -mpowerpc64" } */
> 
> and 
>   
>   /* { dg-require-effective-target has_arch_ppc64 } */
> 
> matters in this proposed fix, not for the line with ilp32.

Of course :-)

> has_arch_ppc64 uses current_compiler_flags which only incorporates dg-options
> which is placed before the dg-require-effective-target.  I guess it's related
> to how dejaGnu parses lines and sets global variables, for this kind of case,
> we have to put the expected order for now.

Even just to avoid having to uselessly edit hundreds of testcases, it
would be better to just fix the bug!


Segher