https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85077
--- Comment #3 from Matthias Kretz <kretz at kde dot org> --- Ouch, right I didn't think of non-finite values. I.e. -0 < 0 is false... However, this is what I wanted: abs(-inf) -> inf abs( inf) -> inf abs( nan) -> nan abs( -0) -> 0 abs( 0) -> 0 The sign bit manipulation works for all of them. The ternary fails only on the -0 input, no? I'm working on an implementation of wg21.link/p0214r9 that I'd like to contribute to libstdc++, which is why I'm currently looking to remove workarounds and enable the compiler to do const-prop as much as possible. I'd be happy to go with an implementation that uses my_abs if that's the way to go (I guess it is). FWIW, ICC translates `x < 0 ? -x : x` (on float itself) to sign masking. (But then again ICC doesn't conform with default flags either)
