[Bug debug/46252] New: [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[Bug debug/46252] New: [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

           Summary: [4.6 Regression] -fcompare-debug failure (length) with
                    -O -frerun-cse-after-loop -fno-tree-loop-optimize
                    -funroll-loops
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz


Created attachment 22211
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22211
reduced testcase

Compiler output:
$ gcc -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops
-fcompare-debug pr46252.c 
gcc: error: pr46252.c: -fcompare-debug failure (length)

Tested revisions:
r166105 - fail
r161659 - fail
r159696 - OK
4.5 r165781 - OK

[Bug debug/46252] [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2010.10.31 21:35:31
                 CC|                            |ebotcazou at gcc dot
                   |                            |gnu.org
   Target Milestone|---                         |4.6.0
     Ever Confirmed|0                           |1

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> 2010-10-31 21:35:31 UTC ---
It is caused by revision 162618:

http://gcc.gnu.org/ml/gcc-cvs/2010-07/msg00972.html

[Bug debug/46252] [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-01 15:17:58 UTC ---
Created attachment 22221
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22221
gcc46-pr46252.patch

Untested fix.

[Bug debug/46252] [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

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

--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-01 21:16:26 UTC ---
> It is caused by revision 162618:
> 
> http://gcc.gnu.org/ml/gcc-cvs/2010-07/msg00972.html

No, it isn't, this commit only reverts an incorrect change.

[Bug debug/46252] [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-03 08:38:45 UTC ---
Author: jakub
Date: Wed Nov  3 08:38:42 2010
New Revision: 166232

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166232
Log:
    PR debug/46252
    * reload1.c (delete_dead_insn): Use prev_active_insn instead of
    prev_real_insn.
    * gcse.c (insert_insn_end_basic_block): Likewise.

    * gcc.dg/pr46252.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr46252.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gcse.c
    trunk/gcc/reload1.c
    trunk/gcc/testsuite/ChangeLog

[Bug debug/46252] [4.6 Regression] -fcompare-debug failure (length) with -O -frerun-cse-after-loop -fno-tree-loop-optimize -funroll-loops

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46252

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

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

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-03 08:46:12 UTC ---
Fixed.