On Tue, Sep 03, 2019 at 07:20:13PM -0400, Michael Meissner wrote: > On Tue, Sep 03, 2019 at 05:56:03PM -0500, Segher Boessenkool wrote: > > Hi! > > > > On Mon, Aug 26, 2019 at 05:43:41PM -0400, Michael Meissner wrote: > > > /* This file implements a RTL pass that looks for pc-relative loads of the > > > address of an external variable using the PCREL_GOT relocation and a > > > single > > > load/store that uses that GOT pointer. > > > > Does this work better than having a peephole for it? Is there some reason > > you cannot do this with a peephole? > > Yes. Peepholes only look at adjacent insns.
Huh. Wow. Would you believe I never knew that (or I forgot)? Well, that explains why peepholes aren't very effective for us at all, alright! > This optimization allows the load > of the GOT address to be separated from the eventual load or store. > > Peephole2's are likely too early, because you really, really, really don't > want > any other pass moving things around. That is a bit worrying... What can go wrong? Segher
