On Tue, 7 Jan 2014, Bill Schmidt wrote: > +@item -maltivec=be > +@opindex maltivec=be > +Generate Altivec instructions using big-endian element order, > +regardless of whether the target is big- or little-endian. > + > +@item -maltivec=le > +@opindex maltivec=le > +Generate Altivec instructions using little-endian element order, > +regardless of whether the target is big- or little-endian. This > +option is currently ignored for big-endian targets, but may be enabled > +in the future.
I don't understand what "using big-endian element order" or "using little-endian element order" means. Is this about the interpretation of element numbers in AltiVec intrinsics? (In GNU C vector indexing with array notation, GENERIC, GIMPLE and RTL, vector element numbers are always in memory order like in arrays, so a command-line option like this *shouldn't* affect anything other than intrinsics. Cf. the ARM NEON code that deals with flipping element order conventions for big endian so that intrinsics can follow the ARM convention while GNU C, GENERIC, GIMPLE and RTL follow the convention that the architecture-independent compiler expects.) -- Joseph S. Myers jos...@codesourcery.com
