This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Returning optional is much safer.
The previous API had potential to cause use of undefined variables, if
the value passed by pointer was accidentally read afterwards.
Differential Revision: https://reviews.llvm.org/D48137
llvm-svn: 334634
Provide checkedAdd and checkedMul functions, providing checked
arithmetic on signed integers.
Differential Revision: https://reviews.llvm.org/D43704
llvm-svn: 326516
Fangrui Song