Over the last year, LLVM apparently learned how to optimize many
FORTIFY'ed functions. I went through the list of functions it optimizes,
and simplified their implementations here.
This is more than a code health thing; __bos_trivially_ge expands to a
branch that's not eliminated until after inlining, so it can actually
cause some functions (like one of std::string's ctors) to become
uninlineable.
Bug: 148189733
Test: hand-checked the IR we get for each of the changed functions. Many
get optimized to their non-_chk variant when appropriate. Others
will get optimized to non-_chk versions when bos == -1. Bug repro
also now shows all 'inline's.
Change-Id: Ic360818ad9daaeda3958e1282af41087f85122a3
2f7876596e