- GCC does not recognize $fcsr0, uses $r0 instead.
- GCC does not implement __builtin_thread_pointer, which can be
obtained directly through $tp.
Reviewed By: SixWeining
Differential Revision: https://reviews.llvm.org/D140545
Initial builtins for LoongArch.
Add loongarch64 to ALL_CRT_SUPPORTED_ARCH list.
Support fe_getround and fe_raise_inexact in builtins.
Differential Revision: https://reviews.llvm.org/D136338