Issue with Clang on Windows and compiler-rt builtins

When __int128 operations are used, Clang on Windows generate calls to
compiler-rt builtins (__udivti3 etc.) instead of generating inline
optimized assembly directly.

LLVM does not inline division or modulo for 128bit operands. Way too
much code.

Thanks for the pointer.

After checking with Compiler Explorer , I realized my mistake. GCC
and Clang on Linux will constant fold __int128 if possible, otherwise __udivti3
etc. function calls will still be emitted.

I submitted a patch to compiler-rt for this at ⚙ D41813 [builtins] Enable CRT_HAS_128BIT for MSVC.
Hope I am doing it correctly.

Rong Jie