fhahn added inline comments.
================
Comment at: clang/lib/CodeGen/CodeGenFunction.h:523
return getLangOpts().C11 || getLangOpts().C17 || getLangOpts().C2x;
}
----------------
aaron.ballman wrote:
> 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
For C11 and later, it should be 6.8.5.6, which says:
```
An iteration statement may be assumed by the implementation to terminate if its
controlling expression is not a constant expression,171) and none of the
following operations are performed in its body, controlling expression or (in
the case of a for statement) its expression-3:172)
— input/output operations
— accessing a volatile object
— synchronization or atomic operations.
```
It would probably be good to refer to C11 6.8.5.6 here, and the equivalent for
C++ (6.9.2.3.1)?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D96418/new/
https://reviews.llvm.org/D96418
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