This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: [Combine] Unusual behaviour in combine
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