From: Segher Boessenkool <segher@kernel.crashing.org>
To: Peter Bergner <bergner@linux.ibm.com>
Cc: Vladimir N Makarov <vmakarov@redhat.com>,
Jeff Law <law@redhat.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [RFC][PATCH LRA] WIP patch to fix one part of PR87507
Date: Sat, 20 Oct 2018 21:05:00 -0000 [thread overview]
Message-ID: <20181020165335.GG1712@gate.crashing.org> (raw)
In-Reply-To: <ca2d2a92-e8bc-4237-15cb-a3d06617b53b@linux.ibm.com>
On Fri, Oct 19, 2018 at 05:39:07PM -0500, Peter Bergner wrote:
> On 10/19/18 4:16 PM, Peter Bergner wrote:
> > Thoughts? I'll note that this does not fix the S390 bugs, since those seem
> > to be due to problems with early clobber operands and "matching" constraint
> > operands. I'm still working on that and hope to have something soon.
> [snip]
> > * lra-constraints.c (process_alt_operands): Abort on illegal hard
> > register usage. Prefer reloading non hard register operands.
>
> I stand corrected. Using this patch, plus Segher's combine patch, I am
> able to bootstrap s390x-linux. I'm running the test suite to see whether
> that looks clean as well. Maybe those s390 issues were related to combine
> pushing hard regs into patterns and we just weren't handling them well?
The only such case where combine does something wrong (or that results in
broken code, anyway) is the register vars with asm, AFAIK. It can of course
make like harder for LRA/reload, but that shouldn't affect correctness.
It would be interesting to hear about other cases.
Segher
next prev parent reply other threads:[~2018-10-20 16:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-19 21:51 Peter Bergner
2018-10-20 6:47 ` Peter Bergner
2018-10-20 21:05 ` Segher Boessenkool [this message]
2018-10-22 22:08 ` Jeff Law
2018-10-23 0:25 ` Peter Bergner
2018-10-23 1:16 ` Peter Bergner
2018-10-27 23:25 ` Peter Bergner
2018-11-06 20:28 ` Jeff Law
2018-11-07 0:14 ` Segher Boessenkool
2018-11-07 16:29 ` Peter Bergner
2018-11-07 17:36 ` Jeff Law
2018-11-07 17:45 ` Peter Bergner
2018-11-08 2:17 ` Peter Bergner
2018-11-08 22:07 ` Jeff Law
2018-11-08 22:42 ` Peter Bergner
2018-10-23 4:54 ` Segher Boessenkool
2018-10-23 6:47 ` Peter Bergner
2018-10-25 0:55 ` Jeff Law
2018-10-20 17:23 ` Segher Boessenkool
2018-10-22 23:23 ` Vladimir Makarov
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