From: Jakub Jelinek <jakub@redhat.com>
To: Richard Earnshaw <rearnsha@arm.com>
Cc: Christophe Lyon <christophe.lyon@linaro.org>,
Jeff Law <law@redhat.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
rsandifo@linux.vnet.ibm.com
Subject: Re: RFA: cache enabled attribute by insn code
Date: Tue, 27 May 2014 15:27:00 -0000 [thread overview]
Message-ID: <20140527152726.GO10386@tucnak.redhat.com> (raw)
In-Reply-To: <5384AC23.40701@arm.com>
On Tue, May 27, 2014 at 04:15:47PM +0100, Richard Earnshaw wrote:
> On 27/05/14 15:08, Richard Sandiford wrote:
> > Hmm, is this because of "insn_enabled"? If so, how did that work before
> > the patch? LRA already assumed that the "enabled" attribute didn't depend
> > on the operands.
>
> Huh! "enabled" can be applied to each alternative. Alternatives are
> selected based on the operands. If LRA can't cope with that we have a
> serious problem. In fact, a pattern that matches but has no enabled
> alternatives is meaningless and guaranteed to cause problems during
> register allocation.
This is not LRA fault, but the backend misusing the "enabled" attribute
for something it wasn't designed for, and IMHO against the documentation
of the attribute too.
Just look at the original submission why it has been added.
Jakub
next prev parent reply other threads:[~2014-05-27 15:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-20 8:16 Richard Sandiford
2014-05-20 8:17 ` Richard Sandiford
2014-05-20 14:42 ` Mike Stump
2014-05-20 17:50 ` Jeff Law
2014-05-20 21:37 ` Richard Sandiford
2014-05-23 18:19 ` Jeff Law
2014-05-27 13:12 ` Christophe Lyon
2014-05-27 13:37 ` Ramana Radhakrishnan
2014-05-27 14:59 ` Christophe Lyon
2014-05-27 14:08 ` Richard Sandiford
2014-05-27 14:18 ` Richard Sandiford
2014-05-27 15:07 ` Richard Sandiford
2014-05-27 16:36 ` Christophe Lyon
2014-05-28 14:01 ` Yufeng Zhang
2014-05-29 9:43 ` Richard Earnshaw
2014-05-29 10:45 ` Richard Sandiford
2014-05-27 15:15 ` Richard Earnshaw
2014-05-27 15:27 ` Jakub Jelinek [this message]
2014-05-27 15:40 ` Richard Earnshaw
2014-05-27 15:50 ` Jakub Jelinek
2014-05-27 16:01 ` Richard Earnshaw
2014-05-27 16:09 ` Richard Sandiford
2014-05-27 16:21 ` Richard Earnshaw
2014-05-27 16:31 ` Richard Sandiford
2014-05-28 15:11 ` Richard Earnshaw
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