[Bug tree-optimization/16447] New: out of ssa generates bloated code

[Bug tree-optimization/16447] New: out of ssa generates bloated code

[dann at godzilla dot ics dot uci dot edu]

The the .tailc dump for the function combine.c:cant_combine_insn_p
looks like this: 
[snip]
<L23>:;
  T.150_24 = dest_5->u.fld[0].rtuint;
  if (T.150_24 > 52) goto <L35>; else goto <L24>;

<L24>:;
  T.151_26 = fixed_regs[T.150_24];
  if (T.151_26 != 0) goto <L35>; else goto <L25>;

<L25>:;
  T.152_29 = regclass_map[T.150_24];
  T.153_30 = T.152_29 - 1;
  if (T.153_30 <= 3) goto <L35>; else goto <L26>;

<L26>:;
  if (T.152_29 == 7) goto <L35>; else goto <L27>;

<L27>:;
  if (T.152_29 == 5) goto <L35>; else goto <L28>;

<L28>:;
  if (T.152_29 == 6) goto <L35>; else goto <L29>;

<L29>:;
  if (T.152_29 == 13) goto <L35>; else goto <L30>;

<L30>:;
  if (T.152_29 == 14) goto <L31>; else goto <L35>;

<L31>:;

  # T.139_1 = PHI <0(7), 1(25), 0(2), 1(0), 0(24), 0(8), 1(23), 1(22), 1(21),
1(20), 1(19), 0(18), 0(17), 1(16), 1(15), 1(14), 1(13), 1(12), 1(11)>;
<L35>:;
  return T.139_1;

Note the return value T.139_1

The .optimized dump looks like: 

[snip]
<L75>:;
  T.139 = 1;
  goto <bb 26> (<L35>);

<L27>:;
  if (T.152 == 5) goto <L76>; else goto <L28>;

<L76>:;
  T.139 = 1;
  goto <bb 26> (<L35>);

<L28>:;
  if (T.152 == 6) goto <L77>; else goto <L29>;

<L77>:;
  T.139 = 1;
  goto <bb 26> (<L35>);

<L29>:;
  if (T.152 == 13) goto <L78>; else goto <L30>;

<L78>:;
  T.139 = 1;
  goto <bb 26> (<L35>);

<L30>:;
  if (T.152 == 14) goto <L31>; else goto <L79>;

<L79>:;
  T.139 = 0;
  goto <bb 26> (<L35>);

<L31>:;
  T.139 = 1;

<L35>:;
  return T.139;

Not that T.139 is assigned 1 in a lot of BBs, followed by a jumb to the return
statement. 
The code would be much smaller if there was a only 1 assignment that all the ifs
jump to.

-- 
           Summary: out of ssa generates bloated code
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dann at godzilla dot ics dot uci dot edu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[dann at godzilla dot ics dot uci dot edu]

------- Additional Comments From dann at godzilla dot ics dot uci dot edu  2004-07-09 03:30 -------
Created an attachment (id=6716)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6716&action=view)
compilable file containing the function this PR talks about.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-07-09 04:02 -------
Confirmed, here is a simple example:
int f(int i, int b, int c)
{
  if (i)
    return 1;
  if (b)
    return 1;
  if (c)
    return 1;
  return 0;
}

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |compile-time-hog, TREE
   Last reconfirmed|0000-00-00 00:00:00         |2004-07-09 04:02:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-09-28 20:12 -------
I have a semi fix (well one [or is two less] less BB), the fix for that part was in PHI-OPT but the rest 
would need to be in outof-ssa.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[amacleod at redhat dot com]

------- Additional Comments From amacleod at redhat dot com  2004-09-29 20:21 -------
I think the best way to do this is to add a short analysis pass in the out of
ssa pass, immediately before we commit the final edge insertions.

Take a look at the predecessors of each basic block, and find any edges which
have the same set of stmts on it. Commit one of these edges, if it generates a
new basic block, simply redirect all the other matching edges to that block, and
remove the PENDING_STMTS list for those edges.

I've started a basic implementation.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2004-07-09 04:02:25         |2004-09-29 20:21:29
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-06 12:46 -------
Subject: Bug 16447

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	tree-cleanup-branch
Changes by:	amacleod@gcc.gnu.org	2004-10-06 12:46:04

Modified files:
	gcc            : ChangeLog tree-cfg.c tree-flow.h 
	                 tree-optimize.c tree-outof-ssa.c 

Log message:
	2004-10-06  Andrew MacLeod  <amacleod@redhat.com>
	
	PR tree-optimization/16447
	* tree-cfg.c (bsi_commit_one_edge_insert): Rename from
	bsi_commit_edge_inserts_1, and make funtion external.  Return new block.
	(bsi_commit_edge_inserts): Use renamed bsi_commit_one_edge_insert.
	* tree-optimize.c (pass_cleanup_cfg_post_optimizing): Enable listing.
	* tree-flow.h (bsi_commit_one_edge_insert): Extern decl.
	* tree-outof-ssa.c (rewrite_trees): Don't commit edges here.
	(same_stmt_list_p): New.  Return TRUE if edge is to be forwarded.
	(identical_copies_p): New.  Return true is two copies are the same.
	(identical_stmt_lists_p): New.  Return true if stmt lists are the same.
	(analyze_edges_for_bb): New.  Determine how best to insert edge stmts
	for a basic block.
	(perform_edge_inserts): New.  Determine what to do with all stmts that
	have been inserted on edges.
	(remove_ssa_form):  Analyze and commit edges from here.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=tree-cleanup-branch&r1=2.5512.2.2&r2=2.5512.2.3
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-cfg.c.diff?cvsroot=gcc&only_with_tag=tree-cleanup-branch&r1=2.55.2.3&r2=2.55.2.4
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-flow.h.diff?cvsroot=gcc&only_with_tag=tree-cleanup-branch&r1=2.46.2.2&r2=2.46.2.3
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-optimize.c.diff?cvsroot=gcc&only_with_tag=tree-cleanup-branch&r1=2.47.2.3&r2=2.47.2.4
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-outof-ssa.c.diff?cvsroot=gcc&only_with_tag=tree-cleanup-branch&r1=2.22.2.1&r2=2.22.2.2



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-06 13:03 -------
Patch here: <http://gcc.gnu.org/ml/gcc-patches/2004-10/msg00488.html>, applied to tcb already.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
OtherBugsDependingO|                            |17652
              nThis|                            |
           Keywords|                            |patch
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-11-02 00:23 -------
Subject: Bug 16447

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	amacleod@gcc.gnu.org	2004-11-02 00:23:05

Modified files:
	gcc            : ChangeLog tree-cfg.c tree-flow.h 
	                 tree-optimize.c tree-outof-ssa.c 

Log message:
	2004-11-01  Andrew MacLeod  <amacleod@redhat.com>
	
	PR tree-optimization/16447
	* tree-cfg.c (bsi_commit_one_edge_insert): Rename from
	bsi_commit_edge_inserts_1, and make funtion external.  Return new block.
	(bsi_commit_edge_inserts): Use renamed bsi_commit_one_edge_insert.
	* tree-optimize.c (pass_cleanup_cfg_post_optimizing): Enable listing.
	* tree-flow.h (bsi_commit_one_edge_insert): Extern decl.
	* tree-outof-ssa.c (rewrite_trees): Don't commit edges here.
	(same_stmt_list_p): New.  Return TRUE if edge is to be forwarded.
	(identical_copies_p): New.  Return true is two copies are the same.
	(identical_stmt_lists_p): New.  Return true if stmt lists are the same.
	(analyze_edges_for_bb): New.  Determine how best to insert edge stmts
	for a basic block.
	(perform_edge_inserts): New.  Determine what to do with all stmts that
	have been inserted on edges.
	(remove_ssa_form):  Analyze and commit edges from here.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.6125&r2=2.6126
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-cfg.c.diff?cvsroot=gcc&r1=2.96&r2=2.97
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-flow.h.diff?cvsroot=gcc&r1=2.57&r2=2.58
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-optimize.c.diff?cvsroot=gcc&r1=2.60&r2=2.61
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-outof-ssa.c.diff?cvsroot=gcc&r1=2.27&r2=2.28



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447

[Bug tree-optimization/16447] out of ssa generates bloated code

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-02 01:29 -------
Fixed on the mainline now.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.1.0                       |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16447