[PATCH] D96418: [clang] Refactor mustprogress handling, add it to all loops in c++11+.

Aaron Ballman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Feb 11 04:07:14 PST 2021


aaron.ballman added inline comments.


================
Comment at: clang/lib/CodeGen/CodeGenFunction.h:523
     return getLangOpts().C11 || getLangOpts().C17 || getLangOpts().C2x;
   }
 
----------------
jdoerfert wrote:
> fhahn wrote:
> > jdoerfert wrote:
> > > Can you modify the documentation to talk about what loops must make progress, this is the code below transcribed. 
> > > 
> > > Also, I don't see how this works. Should the const-ness of the condition not be related to the standard/language to make a decision?
> > > Can you modify the documentation to talk about what loops must make progress, this is the code below transcribed.
> > 
> > I added some comments. I hope they make things clearer.
> > 
> > > Also, I don't see how this works. Should the const-ness of the condition not be related to the standard/language to make a decision?
> > 
> > The `functionMustProgress` call applies the C++ rules. So C++11 and above is already handled by the call.
> > 
> > Afterwards, loops with constant conditions never have to make progress (C++ before 11, any C version). Loops with non-constant conditions have to make progress in C11 and later.
> > 
> > Hopefully the comment makes that clearer.
> Now, even I understand this. Thanks :)
>  Loops with non-constant conditions have to make progress in C11 and later.

Can you point me to the part of the C11 (or later) standards that state this? I don't see wording like http://eel.is/c++draft/intro.progress#1 in 5.1.2.4 in http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2596.pdf


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  https://reviews.llvm.org/D96418/new/

https://reviews.llvm.org/D96418



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