[PATCH] D73020: [Sema] Perform call checking when building CXXNewExpr

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri added inline comments.


================
Comment at: clang/lib/Sema/SemaChecking.cpp:3887-3891
         if (!I.isPowerOf2()) {
           Diag(Arg->getExprLoc(), diag::err_alignment_not_power_of_two)
               << Arg->getSourceRange();
           return;
         }
----------------
rsmith wrote:
> Oh, I wasn't aware we gave an error for this case. We can't issue an error for passing a bad alignment to `operator new` -- it's valid for code to pass a bad alignment, but results in undefined behavior. The same is true for `aligned_alloc` and `posix_memalign`, so we should presumably just downgrade this from an error to a warning in general rather than (say) treating `operator new` as a special case.
> 
> For example, this is valid and may be reasonable in some cases:
> 
> ```
> template<int N> void *make() {
>   if ((N & (N-1)) == 0)
>     return operator new(N, std::align_val_t(N));
>   else
>     return operator new(N);
> }
> void *p = make<7>();
> ```
Hmm.
I'll post that as a followup patch here.


Repository:
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  https://reviews.llvm.org/D73020/new/

https://reviews.llvm.org/D73020