Hello, the -ffast-math command line option sets a bunch of other flags internally, as implemented in set_fast_math_flags. It is possible to selectively override those flags on the command line as well.
I'm now wondering under what circumstances the __FAST_MATH__ macro should still be defined. This is currently implemented in the fast_math_flags_set_p routine, which checks the status of *some* (but not all!) of the flags implied by -ffast-math. This has the effect that e.g. after -ffast-math -fno-finite-math-only the __FAST_MATH__ macro is no longer predefined, but after -ffast-math -fno-associative-math the __FAST_MATH__ macro still *is* predefined, even though both -ffinite-math-only and -fassociative-math are implied by -ffast-math. Is this deliberate? (If so, is it documented somewhere?) Or is this just a bug and fast_math_flags_set_p ought to check all flags implied by -ffast-math? Bye, Ulrich -- Dr. Ulrich Weigand GNU/Linux compilers and toolchain ulrich.weig...@de.ibm.com
