This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [Patch] Fix for PR middle-end/38059, Compile time regression
- From: Steve Ellcey <sje at cup dot hp dot com>
- To: Diego Novillo <dnovillo at google dot com>, Jeff Law <law at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 01 Dec 2008 14:57:16 -0800
- Subject: Re: [Patch] Fix for PR middle-end/38059, Compile time regression
- References: <200811211825.mALIP2O04820@lucas.cup.hp.com> <4927353B.1000304@redhat.com> <b798aad50811211436r121b6c81j146fac5915e80a17@mail.gmail.com>
- Reply-to: sje at cup dot hp dot com
On Fri, 2008-11-21 at 17:36 -0500, Diego Novillo wrote:
> On Fri, Nov 21, 2008 at 17:24, Jeff Law <law@redhat.com> wrote:
>
> > I'll support removal if someone goes through and
> > verifies removal of the pass has little effect on a reasonable body of code
> > (say gcc itself).
>
> Agreed. This pass is pretty uninteresting nowadays. We were tempted
> to take it out when working on tuples, but the changes we had were
> already too invasive. I also support tossing this one out.
>
>
> Diego.
I tried removing the 'useless' pass (remove_useless_stmts) and am
running into an odd situation I don't quite understand. If I change
passes.c to remove the line:
NEXT_PASS (pass_remove_useless_stmts);
Then the compiler dies with:
x.c:6: internal compiler error: in verify_curr_properties, at
passes.c:1085
It looks like this is dying in the lower_cfg pass because the compiler
expects PROP_gimple_any to be set but finds that it isn't. However the
useless pass doesn't claim to provide this property, indeed it requires
it just like the lower_cfg pass does. So I don't understand how
removing the useless pass is messing this up. Does someone understand
what is happening here?
Steve Ellcey
sje@cup.hp.com