[PATCH] D75285: Mark restrict pointer or reference to const as invariant

Tue Mar 3 05:02:33 PST 2020

jeroen.dobbelaere added a comment.

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).

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https://reviews.llvm.org/D75285