From: Jakub Jelinek <jakub@redhat.com>
To: Michael Eager <eager@eagerm.com>
Cc: Alexandre Oliva <aoliva@redhat.com>,
Bernd Schmidt <bernds@codesourcery.com>,
gcc-patches@gcc.gnu.org
Subject: Re: introduce --param max-vartrack-expr-depth
Date: Wed, 20 Jul 2011 20:55:00 -0000 [thread overview]
Message-ID: <20110720202339.GJ2687@tyan-ft48-01.lab.bos.redhat.com> (raw)
In-Reply-To: <4E27358C.7050109@eagerm.com>
On Wed, Jul 20, 2011 at 01:07:40PM -0700, Michael Eager wrote:
> I've run into a problem with this change when building microblaze-xilinx-elf.
>
> When compiling _divdi3.o, cselib_expand_value_rtx_1 returns a huge rtx
> tree for variable _r1 when max_depth is greater than 17. If -g is
> specified, this later results in attempting to generate a DWARF location
> list much larger than the 0xffff size limit, resulting in an assert failure.
I think Alex is working on a patch which will hopefully improve it.
In 4.6-RH in the mean time we are defaulting max-vartrack-expr-depth to 12
instead, perhaps that would be better than 10.
As for the 0xffff size limit, I'd say we should handle it instead of
asserting, e.g. if the size is 64K or more, we could emit there a single
DW_OP_call4 + DW_TAG_dwarf_procedure that would contain it.
Or just drop the range on the floor, still better than ICE.
> 2011-07-20 Michael Eager <eager@eagercon.com>
>
> * params.def (PARAM_MAX_VARTRACK_EXPR_DEPTH): Default to 10.
>
> Index: gcc/params.def
> ===================================================================
> --- gcc/params.def (revision 176533)
> +++ gcc/params.def (working copy)
> @@ -845,7 +845,7 @@
> DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
> "max-vartrack-expr-depth",
> "Max. recursion depth for expanding var tracking expressions",
> - 20, 0, 0)
> + 10, 0, 0)
Jakub
next prev parent reply other threads:[~2011-07-20 20:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-30 12:24 Alexandre Oliva
2011-05-30 12:30 ` Jakub Jelinek
2011-05-30 12:39 ` Bernd Schmidt
2011-05-31 17:47 ` Alexandre Oliva
2011-05-31 18:16 ` Jakub Jelinek
2011-06-01 20:09 ` Alexandre Oliva
2011-06-01 22:29 ` Alexandre Oliva
2011-06-02 8:47 ` Jakub Jelinek
2011-06-02 10:07 ` Bernd Schmidt
2011-06-03 1:42 ` Alexandre Oliva
2011-07-20 20:48 ` Michael Eager
2011-07-20 20:55 ` Jakub Jelinek [this message]
2011-07-20 21:00 ` Michael Eager
2011-07-20 21:04 ` Jakub Jelinek
2011-07-21 0:10 ` Michael Eager
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110720202339.GJ2687@tyan-ft48-01.lab.bos.redhat.com \
--to=jakub@redhat.com \
--cc=aoliva@redhat.com \
--cc=bernds@codesourcery.com \
--cc=eager@eagerm.com \
--cc=gcc-patches@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).