On Tue, 21 Mar 2023, Jeff Law via Gcc-patches wrote:
> On 3/21/23 11:00, Qing Zhao via Gcc-patches wrote:
> >
> >> On Mar 21, 2023, at 12:56 PM, Paul Koning <paulkon...@comcast.net> wrote:
> >>
> >>> On Mar 21, 2023, at 11:01 AM, Qing Zhao via Gcc-patches
> >>> <gcc-patches@gcc.gnu.org> wrote:
> >>>
> >>> ...
> >>> Most of the compiler users are not familiar with language standards, or no
> >>> access to language standards. Without clearly documenting such warnings
> >>> along with the option explicitly, the users have not way to know such
> >>> potential impact.
> >>
> >> With modern highly optimized languages, not knowing the standard is going
> >> to get you in trouble. There was a wonderful paper from MIT a few years
> >> ago describing all the many ways C can bite you if you don't know the
> >> rules.
> >
> > Yes, it’s better to know the details of languages standard. -:)
> > However, I don’t think that this is a realistic expectation to the compiler
> > users: to know all the details of a language standard.
> Umm, they really do need to know that stuff.
>
> If the developer fails to understand the language standard, then they're
> likely going to write code that is ultimately undefined or doesn't behave in
> they expect. How is the compiler supposed to guess what the developer
> originally intended? How should the compiler handle the case when two
> developers have different understandings of how a particular piece of code
> should work? In the end it's the language standard that defines how all this
> stuff should work.
>
> Failure to understand the language is a common problem and we do try to emit
> various diagnostics to help developers avoid writing non-conformant code. But
> ultimately if a developer fails to understand the language standard, then
> they're going to be surprised by the behavior of their code.
W h a t.
This subthread concerns documenting the option better ("Without clearly
documenting such warnings ...").
Are you arguing against adding a brief notice to the documentation blurb for
the -ffp-contract= option?
Perplexed,
Alexander
