https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114416
--- Comment #3 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot
Uni-Bielefeld.DE> ---
I've now also found p. 3P-10:
%f0 through %f7 Floating-point fields from structure return
(%d0 through %d6) values with a total size of 32 bytes or less
(%q0 and %q4) appear in the floating-point registers.
and
%o0 through %o5 Outgoing non-floating-point parameters slots use
up to 6 corresponding out registers. Arguments
beyond the sixth extended-word appear on the stack.
The second line seems pretty clear that the %o[0-5] registers are only
for non-fp parameter slots, while the first could be interpreted either
way (fp *fields only* or fp fields in general).
While compatibility with the vendor compiler is a strong argument, in
the end the ABI remains the reference.
