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 wrote: > >> > >>> On Mar 21, 2023, at 11:01 AM, Qing Zhao via Gcc-patches > >>> 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