https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92176
--- Comment #5 from Vladimir Makarov <vmakarov at gcc dot gnu.org> --- (In reply to Andreas Krebbel from comment #3) > 276.ira: > .... > > /* Give the backend a chance to disallow the mode change. */ > if (GET_MODE_CLASS (xmode) != MODE_COMPLEX_INT > && GET_MODE_CLASS (xmode) != MODE_COMPLEX_FLOAT > && !REG_CAN_CHANGE_MODE_P (xregno, xmode, ymode) > /* We can use mode change in LRA for some transformations. */ > && ! lra_in_progress) <----- ? > return -1; > > I'm currently checking whether removing it makes any difference in code > generation - apart from fixing the testcase. As I remember this is necessary for some x86/x86-64 insn descriptions which match operands of different modes one of which is XFmode. For matched reloads LRA uses one pseudo and that creates incorrect RTL. So I think just removing this code will not work for all targets. We should probably somewhere check XFmode or introduce a machine-dependent hook. I'll investigate this problem more.
