https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67609
--- Comment #18 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Jeffrey A. Law from comment #16) > reload has traditionally removed subregs of hardregs and passes after reload > have depended on that behaviour. Doing something similar in lra is > obviously necessary. In fact, subregs of multi-word hard regs isn't ever > supposed to appear in the except during allocation & reloading. But how do you preserve semantics of preserving the upper part then? Do recognized insns never change after reload and thus the target needs to make sure to have insns "separated" enough that the property is preserved solely by means of the selected insn (we don't record the chosen alternatives in the insns, do we?)? > I'm not sure why final has another call to cleanup_subreg_operands. While > git blame blames me, I was just refactoring existing code code back in '98. > > Does that shed any light on what the right behaviour for LRA ought to be?
