yaxunl added a comment. In D75285#1902835 <https://reviews.llvm.org/D75285#1902835>, @jeroen.dobbelaere wrote:
> In D75285#1902788 <https://reviews.llvm.org/D75285#1902788>, @Anastasia wrote: > > > In D75285#1896610 <https://reviews.llvm.org/D75285#1896610>, @rjmccall > > wrote: > > > > > Are you sure `restrict` alone isn't good enough? It doesn't directly > > > tell you that the memory is invariant, but it's usually simple to prove > > > that the memory isn't modified within the `restrict` scope, which might > > > be sufficient. > > > > > > Do you mean to prove in analysis passes? Should we emit some sort of hints > > from the frontend to indicate what to look for? > > > Not sure what you mean with 'hints from the frontend', but D68484 > <https://reviews.llvm.org/D68484> (and later) contain a significant > improvement to clang's handling of restrict. That could make the restrict > path feasible (if that would support the actual use case). I think there are cases that noalias is not sufficient to prove invariance. For example, a global variable, even if we mark it as restrict and we do not modify it in a function, the compiler is still not sure it is invariant in that function, since it may be modified by another thread. In this case, if a user knows that it is invariant in that function, he would just want to mark it as `__invariant__` or `__immutable__`. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D75285/new/ https://reviews.llvm.org/D75285 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
