Re: [PATCH v2] c-family: Add __builtin_assoc_barrier

[Matthias Kretz]

On Wednesday, 8 September 2021 15:44:28 CEST Jason Merrill wrote:
> On 9/8/21 5:37 AM, Matthias Kretz wrote:
> > On Tuesday, 7 September 2021 19:36:22 CEST Jason Merrill wrote:
> >>> case PAREN_EXPR:
> >>> -      RETURN (finish_parenthesized_expr (RECUR (TREE_OPERAND (t, 0))));
> >>> +      if (REF_PARENTHESIZED_P (t))
> >>> +       RETURN (finish_parenthesized_expr (RECUR (TREE_OPERAND (t,
> >>> 0))));
> >>> +      else
> >>> +       RETURN (RECUR (TREE_OPERAND (t, 0)));
> >> 
> >> I think you need to build a new PAREN_EXPR in the assoc barrier case as
> >> well, for it to have any effect in templates.
> > 
> > My intent was to ignore __builtin_assoc_barrier in templates / constexpr
> > evaluation since it's not affected by -fassociative-math anyway. Or do you
> > mean something else?
> 
> I agree about constexpr, but why wouldn't template instantiations be
> affected by -fassociative-math like any other function?

Oh, that seems like a major misunderstanding on my part. I assumed 
tsubst_copy_and_build would evaluate the expressions in template arguments 🤦. 
I'll expand the test and will fix.

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 Dr. Matthias Kretz                           https://mattkretz.github.io
 GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
 stdₓ::simd
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