[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[dje at gcc dot gnu dot org]

--- Additional Comments From dje at gcc dot gnu dot org  2005-02-14 16:03 
---
With -O2/-O3 -funroll loops -fswitch-loops -fpeel-loops, mgrid (and swim) no 
longer regress.  With just -O2/-O3, performance regression for mgrid remains 
(and swim performance dropped dramatically).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-14 
15:52 ---
(In reply to comment #15)
> Is this fixed now? 
No, it regressed again.
See .

-- 
   What|Removed |Added

 Status|WAITING |NEW
   Last reconfirmed|2004-10-22 17:35:50 |2005-02-14 15:52:02
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[steven at gcc dot gnu dot org]

--- Additional Comments From steven at gcc dot gnu dot org  2005-02-14 
10:22 ---
Is this fixed now? 

-- 
   What|Removed |Added

 Status|NEW |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-10 
21:15 ---
I looked at the code generation after Zdenek's patch for PR 19701 and it looks 
much better but I don't 
have a machine to test SPEC on.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[pinskia at gcc dot gnu dot org]

-- 
Bug 18048 depends on bug 19701, which changed state.

Bug 19701 Summary: [4.0 regression] Way too many IVs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19701

   What|Old Value   |New Value

 Status|NEW |RESOLVED
 Resolution||FIXED

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts (register pressure)

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-30 
04:36 ---
PR 19701 is an example of where ivopts causes a regression in that we create 
too many IVs.

-- 
   What|Removed |Added

  BugsThisDependsOn||19701


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[steven at gcc dot gnu dot org]

--- Additional Comments From steven at gcc dot gnu dot org  2005-01-23 
13:17 ---
Andrew, 30 lines is quite OK to paste if you rename things a bit ;-) 
You'll find that mgrid.f is already available on the web anyway: 
http://www.cs.duke.edu/~tavi/scheduling/mgrid.f 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[steven at gcc dot gnu dot org]

--- Additional Comments From steven at gcc dot gnu dot org  2005-01-23 
00:24 ---
The mgrid score on AMD64 jumps 30% with my patch for PR19464 applied. 

-- 
   What|Removed |Added

 CC||mark at codesourcery dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-22 
21:37 ---
If I have a smaller testcase but the loop is still looks like what is in mgrid 
can I paste it here, it is only 
30 lines?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-22 
17:54 ---
(In reply to comment #8)
> Actually I think the remaining issues of the mgrid performance regression are 
> caused by PR 19038.

Well I looked the assembly and it looks like a regresiter allocator problem now 
because with -fno-
ivopts we don't spill but with it turned we do.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[dberlin at gcc dot gnu dot org]

-- 
Bug 18048 depends on bug 19038, which changed state.

Bug 19038 Summary: [4.0 Regression] tree-ssa causing loops to have more than 
one BB
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19038

   What|Old Value   |New Value

 Status|NEW |ASSIGNED
 Status|ASSIGNED|RESOLVED
 Resolution||FIXED

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-06 
23:02 ---
Actually I think the remaining issues of the mgrid performance regression are 
caused by PR 19038.

-- 
   What|Removed |Added

  BugsThisDependsOn||19038


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-26 
14:58 ---
(In reply to comment #6)
> PR 19038 shows up here also but not introduced by ivopts related.
Though IV-OPTS helps fixing some of these.

-- 
   What|Removed |Added

 CC||pinskia at gcc dot gnu dot
   ||org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-26 
14:50 ---
PR 19038 shows up here also but not introduced by ivopts related.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[neroden at gcc dot gnu dot org]

-- 
   What|Removed |Added

OtherBugsDependingO||18693
  nThis||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[cvs-commit at gcc dot gnu dot org]

--- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-27 20:27 
---
Subject: Bug 18048

CVSROOT:/cvs/gcc
Module name:gcc
Changes by: [EMAIL PROTECTED]   2004-10-27 20:27:21

Modified files:
gcc: ChangeLog fold-const.c tree-ssa-loop-ivopts.c 
 tree-ssa-loop-niter.c tree.c tree.h 

Log message:
PR tree-optimization/18048
* fold-const.c (try_move_mult_to_index): New function.
(fold): Use try_move_mult_to_index.
* tree-ssa-loop-ivopts.c (try_add_cand_for): Prefer common candidates.
* tree-ssa-loop-niter.c (number_of_iterations_cond): Produce
an all-ones unsigned constant without extra bits.
* tree.c (build_low_bits_mask): New function.
* tree.h (build_low_bits_mask): Declare.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.6052&r2=2.6053
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/fold-const.c.diff?cvsroot=gcc&r1=1.468&r2=1.469
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-ivopts.c.diff?cvsroot=gcc&r1=2.20&r2=2.21
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-niter.c.diff?cvsroot=gcc&r1=2.13&r2=2.14
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree.c.diff?cvsroot=gcc&r1=1.440&r2=1.441
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree.h.diff?cvsroot=gcc&r1=1.640&r2=1.641



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[rakdver at atrey dot karlin dot mff dot cuni dot cz]

--- Additional Comments From rakdver at atrey dot karlin dot mff dot cuni dot cz  
2004-10-22 21:16 ---
Subject: Re:  [4.0 Regression] mgrid loop performance regression with ivopts

> Daniel's DOM loop depth patch might help with this problem as well.
> http://gcc.gnu.org/ml/gcc-patches/2004-10/msg00931.html

Probably not (although large part of the regression is indeed caused by
ivopts -- dom interaction, it seems to be of quite different type).

I am just testing a patch that significantly decreases the regression
(unfortunately, some 10% remain even with the patch; hopefully I will
find reason for them soon).

Zdenek


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[dje at gcc dot gnu dot org]

--- Additional Comments From dje at gcc dot gnu dot org  2004-10-22 18:39 ---
Daniel's DOM loop depth patch might help with this problem as well.
http://gcc.gnu.org/ml/gcc-patches/2004-10/msg00931.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

--- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-22 17:35 
---
I think this can be confirmed because you can see the drop on Diego's SPEC tester:
.

-- 
   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed||1
   Last reconfirmed|-00-00 00:00:00 |2004-10-22 17:35:50
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[matz at suse dot de]

--- Additional Comments From matz at suse dot de  2004-10-19 16:46 ---
Does this go away with "--param iv-consider-all-candidates-bound=70" ? 
(Or with a higher number like 100 or 1000) 

-- 
   What|Removed |Added

 CC||matz at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048

[Bug tree-optimization/18048] [4.0 Regression] mgrid loop performance regression with ivopts

[pinskia at gcc dot gnu dot org]

-- 
   What|Removed |Added

 CC||rakdver at gcc dot gnu dot
   ||org
   Keywords||missed-optimization
Summary|mgrid loop performance  |[4.0 Regression] mgrid loop
   |regression with ivopts  |performance regression with
   ||ivopts
   Target Milestone|--- |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18048