[clang] [compiler-rt] Define signed int overflow with -fms-compatibility (PR #198538)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> I think it's expected, in general, that optimizations are less powerful without nsw markings. But for vectorization, we should usually be able to introduce runtime checks; please file bugs for issues you find.
> 
> That particular example should be straightforward to optimize, I think. We can introduce a runtime check for `u<0x7FFFFFD`. Some brief searching doesn't show an open bug; please file one.

Thanks, I filed https://github.com/llvm/llvm-project/issues/208221 to track this.

https://github.com/llvm/llvm-project/pull/198538