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Re: [PATCH, i386] Add prefixes avoidance tuning for silvermont target
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: Ilya Enkovich <enkovich dot gnu at gmail dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 3 Jul 2014 14:07:44 +0200
- Subject: Re: [PATCH, i386] Add prefixes avoidance tuning for silvermont target
- Authentication-results: sourceware.org; auth=none
- References: <CAFULd4ZGWB72AH44rh3KHKtjJo+uFqFUk6i0T-pX4MaCDNu4eA at mail dot gmail dot com> <CAMbmDYZKq6CJa3tGtAseXzQZceNBSQBQevbgKbHHsyy6vnD8VQ at mail dot gmail dot com> <CAFULd4ZMK9nUwjD670DweBtrY-Ro8D1YomnLkddm7vuz=sm+cg at mail dot gmail dot com> <CAMbmDYYKv+CYsaYH+_gABQomB3o5rfZ+dbO=iiUbKmxjqmKiDg at mail dot gmail dot com>
On Thu, Jul 3, 2014 at 1:50 PM, Ilya Enkovich <email@example.com> wrote:
> I didn't find a nice way to fix peephole2 patterns to take register
> constraints into account. Is there any way to do it?
Use REX_SSE_REGNO_P (REGNO (operands[...])) in the insn C constraint.
> Also fully restrict xmm8-15 does not seem right. It is just costly
> but not fully disallowed.
As said earlier, you can try "Ya*x" as a constraint.