From: DJ Delorie <dj@redhat.com>
To: "Sebastian Perta" <sebastian.perta@renesas.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] RL78 one_cmplhi2 improvement
Date: Tue, 20 Feb 2018 19:44:00 -0000 [thread overview]
Message-ID: <xnbmgjjvs4.fsf@greed.delorie.com> (raw)
In-Reply-To: <000501d3aa44$69a44e30$3cecea90$@renesas.com> (sebastian.perta@renesas.com)
Const type promotion is the bane of embedded developers...
One thing to try is to use (subreg:QI in a define_expand, so that
there's a one_cmplhi2 pattern that expands to two QImode insns that
operate on HImode input/outputs via SUBREGs.
I don't have high hopes of gcc optimizing this properly in all cases,
but it's worth trying.
If it doesn't work out, consider this patch approved, though.
Thanks!
next prev parent reply other threads:[~2018-02-20 19:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-20 12:15 Sebastian Perta
2018-02-20 19:44 ` DJ Delorie [this message]
2018-02-27 15:33 ` Sebastian Perta
2018-02-27 15:52 ` DJ Delorie
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