https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117766
--- Comment #15 from Tom Lane <tgl at sss dot pgh.pa.us> --- (In reply to Richard Earnshaw from comment #14) > GCC implements the following extensions for the v7 architecture: > > +fp - add floating point (as defined by the base architecture) > +simd - add floating point and Neon (as defined by the base architecture) > > However, in Armv8, +fp isn't a permitted implementation, so this isn't > available, leaving just +simd, which enables both FP and Neon. Ah. I begin to understand why it's like this, and now that I look closer I see that +simd does mention enabling floating-point. Still, it's very weird that +simd and +nofp are (more or less) inverses. Would it hurt so much to invent +fp as an alias for +simd? Or if not, the docs for +simd could at least say something like "Note that there is no separate +fp option, since the ARMv8-A specs do not permit implementing FP without SIMD". In any case, many thanks for the insight.
