I think this might not be a shortcoming of MSVC but rather a deliberate design decision. It seems likely that MSVC is failing to apply strict aliasing, but that it's deliberately avoiding it, probably for compatibility reasons with code that wasn't/isn't written to spec. And frankly it can be very onerous to write code that is 100% correct per the standard when dealing with e.g. memory-mapped files; I'm struggling to recall seeing a single case of this.
Decades ago I was a Fortran developer and encountered a very odd bug in which the wrong values were being calculated. After a lot of investigation I tracked it down to a subroutine call in which a hard-coded zero was being passed as an argument. It turned out that in the body of that subroutine the value 4 was being assigned to that parameter for some reason. The side effect was that the value of zero because 4 for the rest of the program execution because Fortran aliases all parameters since it passes by descriptor (or at least DEC FORTRAN IV did so on RSX/11). As you can imagine, hilarity ensued.
Yes. That is the main solution and it is not a good one.
1- `restrict` need to be used carefully. Putting it everywhere in large codebase can lead to pretty tricky bugs if aliasing does occurs under the hood.
1- Restrict is not an official keyword in C++. C++ always has refused to standardize it because it plays terribly with almost any object model.
Are you talking about dropping pointers as a programmer-facing programming language concept (in which case you might find Hylo and similar languages interesting), or dropping pointers from everything - programming languages, their implementations, compilers, etc. (in which case I'm not sure that's even possible)?
Only the first one. Ofc under the hood they will stay, but I think its time to ditch random access model and pull fetching and concept of time closer to programmer
For a system programming language the right solution is to properly track aliasing information in the type system as done in Rust.
Aliasing issues is just yet another instance of C/C++ inferiority holding the industry back. C could've learnt from Fortran, but we ended up with the language we have...
I also wrote about this a while ago: https://forwardscattering.org/post/51
While it is possible to remove most aliasing performance issues in a C or C++ codebase, it is a pain to do it properly.
Decades ago I was a Fortran developer and encountered a very odd bug in which the wrong values were being calculated. After a lot of investigation I tracked it down to a subroutine call in which a hard-coded zero was being passed as an argument. It turned out that in the body of that subroutine the value 4 was being assigned to that parameter for some reason. The side effect was that the value of zero because 4 for the rest of the program execution because Fortran aliases all parameters since it passes by descriptor (or at least DEC FORTRAN IV did so on RSX/11). As you can imagine, hilarity ensued.
https://godbolt.org/z/jva4shbjs
Yes. That is the main solution and it is not a good one.
1- `restrict` need to be used carefully. Putting it everywhere in large codebase can lead to pretty tricky bugs if aliasing does occurs under the hood.
1- Restrict is not an official keyword in C++. C++ always has refused to standardize it because it plays terribly with almost any object model.
Aliasing issues is just yet another instance of C/C++ inferiority holding the industry back. C could've learnt from Fortran, but we ended up with the language we have...