Hi mfvalin,
You can identify the flang using “__PGLLVM__” constant. Below is the sample program:
program main
#ifdef __PGLLVM__
print *, "hello world"
#endif
end program
This above program can be compiled using the command “flang -cpp -o f.out test.f90”.
I have filed a feature request to get the dump of all the predefined macros in flang.