[Bug tree-optimization/46639] New: [4.6 Regression] Missing optimization

[Bug tree-optimization/46639] New: [4.6 Regression] Missing optimization

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

           Summary: [4.6 Regression] Missing optimization
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: d.g.gorbachev@gmail.com
              Host: i686-pc-linux-gnu
            Target: i686-pc-linux-gnu
             Build: i686-pc-linux-gnu


Created attachment 22507
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22507
testcase

gcc -O2 pr46639.c

/tmp/ccJzJXqb.o: In function `bar.part.0':
pr46639.c:(.text+0x30): undefined reference to `link_error'

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |missed-optimization
   Last reconfirmed|                            |2010.11.24 12:18:23
                 CC|                            |hubicka at gcc dot gnu.org
     Ever Confirmed|0                           |1
   Target Milestone|---                         |4.6.0

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-11-24 12:18:23 UTC ---
Hm, confirmed.  We don't clean up redundant conditionals before function
splitting:

  if (n_3(D) > 1023)
    goto <bb 9>;
  else
    goto <bb 3>;

  if (n_3(D) > 1023)
    goto <bb 4>;
  else
    goto <bb 7>;

and fnsplit considers splitting after the first one to be most beneficial.
And we don't inline it back together because
 Not inlining into bar:--param large-stack-frame-growth limit reached.
even though the original stack frame size is zero.

We didn't make the call in main direct either (ipa-reference runs too late
for that).

In the end this of course asks for more early optimizations.

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-24 16:17:02 UTC ---
Well, scheduling one VRP pass could be expensive though and only VRP and DOM
are currently able to optimize these redundant tests away.

Perhaps if for the body of partially inlined functions we kept somewhere the
inlined test or at least its VRP properties, so that VRP pass could use them...

I wonder why in this case partial inlining does something, shouldn't
x > 1023 be predicted with the default predictors unlikely (thus the body be
likely)?

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

--- Comment #3 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> 2011-02-17 17:02:20 UTC ---
I can't reproduce this bug now.

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

--- Comment #4 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> 2011-02-27 19:56:55 UTC ---
Still fails with GCC version 4.6.0 20110226.

[Bug tree-optimization/46639] [4.6 Regression] Missing optimization

[hubicka at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

--- Comment #5 from Jan Hubicka <hubicka at gcc dot gnu.org> 2011-02-28 09:25:28 UTC ---
There is no predictor predicting x > 1023 as unlikely, there is not much you
can easilly guess here ;(

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.0                       |4.6.1

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-25 19:52:52 UTC ---
GCC 4.6.0 is being released, adjusting target milestone.

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-05 11:03:23 UTC ---
Another testcase:
http://gcc.gnu.org/bugzilla/attachment.cgi?id=24188
Richard suggests running pass_vrp_early instead of (or in addition to) pass_ccp
with some more expensive parts of VRP disabled.

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |baryluk at smp dot
                   |                            |if.uj.edu.pl

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-05-05 10:56:28 UTC ---
*** Bug 48880 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.1                       |4.6.2

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-06-27 12:33:04 UTC ---
GCC 4.6.1 is being released.

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.2                       |4.6.3

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-10-26 17:13:49 UTC ---
GCC 4.6.2 is being released.

[Bug tree-optimization/46639] [4.6/4.7 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.3                       |4.6.4

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-01 14:38:59 UTC ---
GCC 4.6.3 is being released.

[Bug tree-optimization/46639] [4.7/4.8/4.9 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.4                       |4.7.4

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-12 15:16:14 UTC ---
GCC 4.6.4 has been released and the branch has been closed.

[Bug tree-optimization/46639] [4.7/4.8/4.9 Regression] Missing optimization due to function splitting and redundant conditionals

[law at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com

--- Comment #13 from Jeffrey A. Law <law at redhat dot com> ---
Another approach would be to do some minimal redundancy elimination as part of
the into-ssa pass.  Having done it before, I know it's pretty easy.

[Bug tree-optimization/46639] [4.7/4.8/4.9/4.10 Regression] Missing optimization due to function splitting and redundant conditionals

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.7.4                       |4.8.4

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
The 4.7 branch is being closed, moving target milestone to 4.8.4.

[Bug tree-optimization/46639] [4.8/4.9/5 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.4                       |4.8.5

--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.4 has been released.

[Bug tree-optimization/46639] [4.8/4.9/5/6 Regression] Missing optimization due to function splitting and redundant conditionals

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.8.5                       |4.9.3

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
The gcc-4_8-branch is being closed, re-targeting regressions to 4.9.3.

[Bug tree-optimization/46639] [4.9/5/6 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.3 has been released.

[Bug tree-optimization/46639] [4.9/5/6 Regression] Missing optimization due to function splitting and redundant conditionals

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46639

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.3                       |4.9.4