On Mon, Jun 17, 2019 at 12:46:31PM -0500, Segher Boessenkool wrote: > So this insn 5 makes it hard to combine with insn 9, because you'll quickly > need a four insn combination, and those are restricted somewhat. But 10+11 > should do something. But it seems it isn't tried at all? Huh.
That's because it is in a different block, of course. What you want isn't the kind of optimisation combine does at all. You probably want to look at something like cprop; or look at how this code is generated, that doesn't seem optimal. Segher
