shafik added a comment. In D110927#3036647 <https://reviews.llvm.org/D110927#3036647>, @ASDenysPetrov wrote:
> In D110927#3036436 <https://reviews.llvm.org/D110927#3036436>, @steakhal > wrote: > >> I'm pretty sure that `int x4 = ((char*)arr)[1];` is supposed to be valid in >> your summary. >> I think it's allowed by the standard to access any valid object via a >> `char*` - according to the strict aliasing rule. >> @shafik WDYT? > > As I found we can legaly treat `char*` as the object of type `char` but not > as an array of objects. This is mentioned in > http://eel.is/c++draft/basic.compound#3.4 //For purposes of pointer > arithmetic ... an object of type T that is not an array element is considered > to belong to an array with one element of type T.// That means that we can > get only the first element of `char*`, otherwise it would be an UB. There is > also a paper to overcome this constraint > http://open-std.org/JTC1/SC22/WG21/docs/papers/2019/p1839r0.pdf > > @aaron.ballman I would like you join the discussion, as we have similar one > in D104285 <https://reviews.llvm.org/D104285>. IIUC the object is `const int arr[42]` and the `(char *)arr` is an expression of pointer type and adding `1` to this is valid. The case you refer to in D104285 <https://reviews.llvm.org/D104285> ended up being a pointer to an array of 2 ints and therefore accessing the third element was out of bounds. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D110927/new/ https://reviews.llvm.org/D110927 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
