On Tue, Aug 11, 2015 at 03:08:29PM -0500, Segher Boessenkool wrote: > [snip code] > > After the prologue there are 46 insns executed before the epilogue. > Many of those are conditional branches (that are not executed); it is > all fall-through until it jumps to the "tail" (the few insns before > the epilogue). GCC knows how to duplicate a tail so that it can do > shrink-wrapping (the original tail needs to be followed by an epilogue, > the duplicated one does not want one); but it can only do it in very > simple cases (one basic block or at least no control flow), and that > is not the case here. We need to handle more generic tails.
And never mind the elephant in the room: the "fastpath" instructions already use a few non-volatile registers, and the shrink-wrap pass (which runs after register allocation) cannot fix that. Ugh. > This seems related to (if not the same as!) <http://gcc.gnu.org/PR51982>. This has that same problem, too. Segher _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
