From: Jakub Jelinek <jakub@redhat.com>
To: Ilya Enkovich <enkovich.gnu@gmail.com>
Cc: Uros Bizjak <ubizjak@gmail.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
"H.J. Lu" <hjl.tools@gmail.com>
Subject: Re: [RFC patch, i386]: Use STV pass to load/store any TImode constant using SSE insns
Date: Fri, 29 Apr 2016 07:41:00 -0000 [thread overview]
Message-ID: <20160429074122.GZ26501@tucnak.zalov.cz> (raw)
In-Reply-To: <CAMbmDYaO34pBEKkhGPjVaz7hZoCE3YBBmqU0aax8kRpf-a02ow@mail.gmail.com>
On Thu, Apr 28, 2016 at 01:45:36PM +0300, Ilya Enkovich wrote:
> > Where does the 2 come from? Is it that the STV pass right now supports only
> > 2 * wordsize modes? Also, I don't think we should treat equally constants
> > that fit into the 32-bit immediates and constants that don't, the latter,
> > when movabsq needs to be used, are more costly.
>
> This variant is for DImode going to split into two SImode. TImode chains
> have own cost model.
Ok. Still, we should make sure the cost of movabsq is significantly higher
than cost of other immediates (not only because the other immediates can be
used directly in the instructions, while for movabsq you need to first use
that insn to initialize some reg and then use that reg in other insn, but
also because of the movabsq latency).
Jakub
next prev parent reply other threads:[~2016-04-29 7:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-27 19:59 Uros Bizjak
2016-04-27 20:35 ` H.J. Lu
2016-04-28 10:36 ` Ilya Enkovich
2016-04-28 10:41 ` Jakub Jelinek
2016-04-28 10:45 ` Ilya Enkovich
2016-04-29 7:41 ` Jakub Jelinek [this message]
2016-04-28 10:43 ` Uros Bizjak
2016-04-28 10:50 ` Ilya Enkovich
2016-04-29 9:49 ` Uros Bizjak
2016-04-29 11:27 ` Ilya Enkovich
2016-04-29 11:56 ` Uros Bizjak
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