[Bug rtl-optimization/21144] New: [4.0/4.1 regression] Apparent infinite loop in reload

[Bug rtl-optimization/21144] New: [4.0/4.1 regression] Apparent infinite loop in reload

[schwab at suse dot de]

The testcase appears to hang inside reload_cse_regs when compiled with -O2.

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           Summary: [4.0/4.1 regression] Apparent infinite loop in reload
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog
          Severity: normal
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: schwab at suse dot de
                CC: gcc-bugs at gcc dot gnu dot org,matz at suse dot de
GCC target triplet: ia64-*-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[schwab at suse dot de]

------- Additional Comments From schwab at suse dot de  2005-04-21 09:42 -------
Created an attachment (id=8698)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8698&action=view)
Testcase


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[pinskia at gcc dot gnu dot org]

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           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.0.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[matz at suse dot de]

------- Additional Comments From matz at suse dot de  2005-04-25 13:20 -------
The problem is in reload_cse_move2add.  It has such a loop: 
                      for (narrow_mode = GET_CLASS_NARROWEST_MODE (MODE_INT); 
                           narrow_mode != GET_MODE (reg); 
                           narrow_mode = GET_MODE_WIDER_MODE (narrow_mode)) 
                        { 
 
where 'reg' comes from a simple SET insn.  In this testcase the insn is: 
  (set (reg:BI r15) (const_int 1)) 
note the mode of reg being BImode.  Now, BImode is in fact a 
FRACTIONAL_INT_MODE, not an INT_MODE (although GET_MODE_CLASS would 
return INT_MODE, so using this instead of hard-coded INT_MODE wouldn't help). 
And GET_CLASS_NARROWEST_MODE(INT_MODE) is QImode, as it will ignore modes 
with precision 1 bit in genmodes.c (I think because the rest of the compiler 
is not prepared to really see an BImode here, but I may be wrong, there 
are not that many instance of GET_CLASS_NARROWEST_MODE and most look safe, 
but will iterate one more time uselessly if started from BImode). 
 
So, this loop starts with QImode, widens the mode each time, and waits for 
it to become equal to the mode of 'reg', i.e. BImode.  This of course 
never happens, so somewhen it is VOIDmode, and that's the fixed point 
of GET_CLASS_NARROWEST_MODE.  So we are endlessly looping. 
 
I've attached the obvious change, which I'm going to regtest now.  It fixes 
this testcase. 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[matz at suse dot de]

------- Additional Comments From matz at suse dot de  2005-04-25 13:26 -------
Created an attachment (id=8734)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8734&action=view)
Patch for above problem


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[wilson at gcc dot gnu dot org]

------- Additional Comments From wilson at gcc dot gnu dot org  2005-04-28 01:15 -------
Confirmed.

The patch is OK for both mainline and the gcc-4.0 branch, assuming it passes the
regtest, in case anyone was waiting for approval.

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           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-04-28 01:15:34
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-29 18:39 -------
Subject: Bug 21144

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	matz@gcc.gnu.org	2005-04-29 18:39:23

Modified files:
	gcc            : ChangeLog postreload.c 

Log message:
	PR rtl-optimization/21144
	* postreload.c (reload_cse_move2add): Check for VOIDmode.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8532&r2=2.8533
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/postreload.c.diff?cvsroot=gcc&r1=2.29&r2=2.30



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-29 18:38 -------
Subject: Bug 21144

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-4_0-branch
Changes by:	matz@gcc.gnu.org	2005-04-29 18:38:44

Modified files:
	gcc            : ChangeLog postreload.c 

Log message:
	PR rtl-optimization/21144
	* postreload.c (reload_cse_move2add): Check for VOIDmode.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.7592.2.204&r2=2.7592.2.205
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/postreload.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.27&r2=2.27.8.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[matz at suse dot de]

------- Additional Comments From matz at suse dot de  2005-04-29 19:03 -------
This is now fixed, but it seems, even though I'm logged in, I can't change the state 
of this report. 

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-29 19:08 -------
Fixed.

(In reply to comment #7)
> This is now fixed, but it seems, even though I'm logged in, I can't change the state 
> of this report. 

I will get you admin. access.


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           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144

[Bug rtl-optimization/21144] [4.0/4.1 regression] Apparent infinite loop in reload

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-06-25 09:56 -------
Subject: Bug 21144

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	tkoenig@gcc.gnu.org	2005-06-25 09:56:38

Modified files:
	libgfortran    : ChangeLog 
	libgfortran/m4 : cshift1.m4 eoshift1.m4 eoshift3.m4 
	libgfortran/generated: cshift1_4.c cshift1_8.c eoshift1_4.c 
	                       eoshift1_8.c eoshift3_4.c eoshift3_8.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gfortran.dg: shift-alloc.f90 

Log message:
	2005-06-25  Thomas Koenig  <Thomas.Koenig@online.de>
	
	PR libfortran/22144
	* m4/cshift1.m4: Remove const from argument ret.
	Populate return array descriptor if ret->data is NULL.
	* m4/eoshift1.m4: Likewise.
	* m4/eoshift3.m4: Likewise.
	* generated/cshift1_4.c:  Regenerated.
	* generated/cshift1_8.c:  Regenerated.
	* generated/eoshift1_4.c:  Regenerated.
	* generated/eoshift1_8.c:  Regenerated.
	* generated/eoshift3_4.c:  Regenerated.
	* generated/eoshift3_8.c:  Regenerated.
	
	2005-06-25  Thomas Koenig <Thomas.Koenig@online.de>
	
	PR libfortran/21144
	* gfortran.dg/shift-alloc.f90:  New testcase.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/ChangeLog.diff?cvsroot=gcc&r1=1.249&r2=1.250
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/m4/cshift1.m4.diff?cvsroot=gcc&r1=1.7&r2=1.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/m4/eoshift1.m4.diff?cvsroot=gcc&r1=1.8&r2=1.9
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/m4/eoshift3.m4.diff?cvsroot=gcc&r1=1.8&r2=1.9
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/cshift1_4.c.diff?cvsroot=gcc&r1=1.6&r2=1.7
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/cshift1_8.c.diff?cvsroot=gcc&r1=1.6&r2=1.7
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/eoshift1_4.c.diff?cvsroot=gcc&r1=1.7&r2=1.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/eoshift1_8.c.diff?cvsroot=gcc&r1=1.7&r2=1.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/eoshift3_4.c.diff?cvsroot=gcc&r1=1.7&r2=1.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/libgfortran/generated/eoshift3_8.c.diff?cvsroot=gcc&r1=1.7&r2=1.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.5684&r2=1.5685
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gfortran.dg/shift-alloc.f90.diff?cvsroot=gcc&r1=NONE&r2=1.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21144