[Bug c/32171] New: ICE w/ -ftree-loop-linear, gcc4.1 and 4.2

[Bug c/32171] New: ICE w/ -ftree-loop-linear, gcc4.1 and 4.2

[bu dot gz dot 200-7 at src dot neostrada dot pl]

gcc segfaults on the code below (which is a simplified des.c from
nettle-1.15.tar.gz). '-ftree-loop-linear' seems to be the trigger,
at least -O1 is required too.
ICEs:
 gcc version 4.2.1 20070531 (prerelease)
 gcc version 4.1.3 20070519 (prerelease)
survives:
 gcc version 4.0.4 20061113 (prerelease)

uname -a:
Linux node 2.6.21.1-g4ead5093 #29 PREEMPT Sun May 6 22:54:15 CEST 2007 i686
GNU/Linux

$ gcc -O1 -ftree-loop-linear -c des.c
des.c: In function 'f':
des.c:4: internal compiler error: Segmentation fault

where des.c is:
---
int f( char *p );
int f( char *p )
{
  unsigned n, w;
  char a[4];

  n = 4;
  do {
    w = *p++;
    do {
      --n;
      w >>= 1;
      a[n] =  w;
    } while ( w >= 16 );
  } while ( n );

  return a[0];
}
---


-- 
           Summary: ICE w/ -ftree-loop-linear, gcc4.1 and 4.2
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bu dot gz dot 200-7 at src dot neostrada dot pl
GCC target triplet: i486-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32171

[Bug tree-optimization/32171] [4.1/4.2 regression] ICE w/ -ftree-loop-linear

[reichelt at gcc dot gnu dot org]

------- Comment #1 from reichelt at gcc dot gnu dot org  2007-12-28 01:42 -------
Confirmed.


-- 

reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |reichelt at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code, monitored
      Known to fail|                            |4.1.2 4.1.3 4.2.0 4.2.1
                   |                            |4.2.2
      Known to work|                            |4.1.0 4.1.1 4.3.0
   Last reconfirmed|0000-00-00 00:00:00         |2007-12-28 01:42:48
               date|                            |
            Summary|ICE w/ -ftree-loop-linear,  |[4.1/4.2 regression] ICE w/
                   |gcc4.1 and 4.2              |-ftree-loop-linear
   Target Milestone|---                         |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32171

[Bug tree-optimization/32171] [4.2 regression] ICE w/ -ftree-loop-linear

[jsm28 at gcc dot gnu dot org]

------- Comment #2 from jsm28 at gcc dot gnu dot org  2008-07-04 22:13 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[4.1/4.2 regression] ICE w/ |[4.2 regression] ICE w/ -
                   |-ftree-loop-linear          |ftree-loop-linear
   Target Milestone|4.1.3                       |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32171

[Bug tree-optimization/32171] [4.2 regression] ICE w/ -ftree-loop-linear

[spop at gcc dot gnu dot org]

------- Comment #3 from spop at gcc dot gnu dot org  2008-11-07 03:46 -------
I will not work on fixing this bug on the 4.2 branch, as it was fixed on the
4.3 and later.  The changes were too large for back-porting.

Sebastian


-- 

spop at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32171