[PATCH] i386: Remove unnecessary clobbers from combine splitters.

[Uros Bizjak]

On Thu, Dec 31, 2020 at 9:40 AM Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>
> Hi Uros,
>
> On Wed, Dec 30, 2020 at 05:44:50PM +0100, Uros Bizjak via Gcc-patches wrote:
> > There is no need for combine splitters to emit insn patterns with clobbers,
> > the pass is smart enough to add clobbers to patterns as necessary.
>
> Nice.  Just one thing: in principle the splitters can be used outside of
> combine, too?  This can lead to insns that do not recog() then?  Is
> there anything that prevents that from happening?

No, combine splitters can't be used outside combine pass. These
splitters only split non-recognizable (non-existing) instructions, and
this is how they are told apart from general split insns. Also, most
of these combine splitters were added recently, but for those I added,
I was not aware of the clobber adding detail (which simplifies some
patterns quite nicely).

Uros.