https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69667
Michael Meissner <meissner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |meissner at gcc dot
gnu.org
--- Comment #7 from Michael Meissner <meissner at gcc dot gnu.org> ---
The error is LRA requires that every register that a constraint targets be a
valid register for the mode. In this case, the 3 move insns that target TFmode
(i.e. long double using the 128-bit IBM extended double format) were using 'ws'
and 'wm' constraints. On power8 systems can match all of the VSX registers by
default. However TFmode/IFmode is restricted to being in the traditional
floating point registers. Reload did not have a problem if some of the
registers mapped by the constraint were unavailable for a given mode, but LRA
doesn't like it.
