From: Alexandre Oliva <aoliva@redhat.com>
To: gcc-patches@gcc.gnu.org
Subject: Re: [trunk<-vta] Re: [vtab] Permit coalescing of user variables
Date: Mon, 01 Jun 2009 07:44:00 -0000 [thread overview]
Message-ID: <oroct8z9dr.fsf@free.oliva.athome.lsd.ic.unicamp.br> (raw)
In-Reply-To: <orskikz9mh.fsf_-_@free.oliva.athome.lsd.ic.unicamp.br> (Alexandre Oliva's message of "Mon\, 01 Jun 2009 04\:38\:46 -0300")
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On Jun 1, 2009, Alexandre Oliva <aoliva@redhat.com> wrote:
> The patch below (ping) implements two other possibilities: refraining
> from coalescing even inlined SSA names, which might enable better debug
> information to be generated, and enabling coalescing of all related
> variables, for better code at the expense of debug information. The
> default remains unchanged.
And the patch below changes the default so that we can optimize more.
This will worsen debug information unless VTA is enabled by default, so
I request a review and approval for inclusion only after VTA or
something equivalent makes it to the trunk.
Ok to install then?
This was bootstrapped and regtested on x86_64-linux-gnu and
i686-pc-linux-gnu, along with the other patches I'm pinging in this
batch.
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for gcc/ChangeLog
from Alexandre Oliva <aoliva@redhat.com>
* common.opt (ftree-coalesce-inlined-vars): Change default.
* doc/invoke.texi: Document default change. Mention
var-tracking-assignments.
Index: gcc/common.opt
===================================================================
--- gcc/common.opt.orig 2009-05-28 20:59:37.000000000 -0300
+++ gcc/common.opt 2009-05-28 21:01:15.000000000 -0300
@@ -1171,7 +1171,7 @@ Common Report Var(flag_tree_ch) Optimiza
Enable loop header copying on trees
ftree-coalesce-inlined-vars
-Common Report Var(flag_ssa_coalesce_vars,1) Init(1) RejectNegative Optimization
+Common Report Var(flag_ssa_coalesce_vars,1) Init(2) RejectNegative Optimization
Permit SSA coalescing of inlined variables only
ftree-coalesce-vars
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi.orig 2009-05-28 20:58:46.000000000 -0300
+++ gcc/doc/invoke.texi 2009-05-28 21:01:05.000000000 -0300
@@ -6473,11 +6473,12 @@ Permit the copyrename pass to subject in
into other variables. This may harm debug information of such inlined
variables, but it will keep variables of the main function apart from
each other, such that they are more likely to contain the expected
-values in a debugging session. This option is enabled by default.
+values in a debugging session.
@item -ftree-coalesce-vars
Permit the copyrename pass to subject all variables to SSA coalescing.
-This may severely limit the ability to debug a program. In the negated
+This may severely limit the ability to debug an optimized program
+compiled without @option{-fvar-tracking-assignments}. In the negated
form, this flag prevents SSA coalescing of user variables, including
inlined ones.
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--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist Red Hat Brazil Compiler Engineer
next prev parent reply other threads:[~2009-06-01 7:44 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-01 19:05 Alexandre Oliva
2007-10-02 9:15 ` Richard Guenther
2007-10-02 21:02 ` Andrew MacLeod
2007-10-03 1:11 ` Alexandre Oliva
2007-10-09 21:32 ` Alexandre Oliva
2009-06-01 7:39 ` [trunk<-vta] " Alexandre Oliva
2009-06-01 7:44 ` Alexandre Oliva [this message]
2009-06-01 16:11 ` Ian Lance Taylor
2009-06-01 17:35 ` Andrew MacLeod
2009-06-01 19:23 ` Alexandre Oliva
2009-06-02 9:54 ` Richard Guenther
2009-06-02 21:42 ` Alexandre Oliva
2009-06-03 1:13 ` Andrew MacLeod
2009-06-03 10:18 ` Richard Guenther
2009-06-03 17:43 ` Alexandre Oliva
2009-06-03 18:06 ` Daniel Jacobowitz
2009-06-03 19:17 ` Alexandre Oliva
2009-06-03 19:45 ` Daniel Jacobowitz
2009-06-03 21:42 ` Alexandre Oliva
2009-06-03 18:18 ` Richard Guenther
2009-06-03 19:15 ` Alexandre Oliva
2009-06-03 19:50 ` Richard Guenther
2009-06-03 19:53 ` Ian Lance Taylor
2009-10-13 21:27 ` Alexandre Oliva
2011-06-04 12:45 ` Alexandre Oliva
2011-06-04 13:02 ` Jakub Jelinek
2011-06-05 21:07 ` Alexandre Oliva
2011-06-06 2:42 ` Alexandre Oliva
2012-04-09 5:56 ` Alexandre Oliva
2012-06-13 8:34 ` Alexandre Oliva
2012-06-13 9:48 ` Richard Guenther
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