[Bug rtl-optimization/46337] New: dse.c:replace_inc_dec mis-use of gen_int_mode

[Bug rtl-optimization/46337] New: dse.c:replace_inc_dec mis-use of gen_int_mode

[bigotp at acm dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

           Summary: dse.c:replace_inc_dec mis-use of gen_int_mode
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bigotp@acm.org


Created attachment 22302
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22302
patch equivalent to part of SVN rev 146451

The parameters to gen_int_mode in dse.c:replace_inc_dec are mis-ordered,
causing an ICE if the optimization actually gets applied.  

This was fixed in mainline by Ian Taylor in SVN revision 146451, but apparently
never made it to a 4.4.x release.  Please add it to the next one.

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

Mikael Pettersson <mikpe at it dot uu.se> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mikpe at it dot uu.se

--- Comment #1 from Mikael Pettersson <mikpe at it dot uu.se> 2010-11-07 09:56:41 UTC ---
Do you have a test case? That would greatly increase the chance of this fix
being added to the 4.4 branch.

(This is not the first error fixed by r146451 but not backported to 4.4, see
http://gcc.gnu.org/ml/gcc-patches/2009-07/msg01120.html for another one.)

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2010.11.07 10:18:15
                 CC|                            |ebotcazou at gcc dot
                   |                            |gnu.org
     Ever Confirmed|0                           |1

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-07 10:18:15 UTC ---
> Do you have a test case? That would greatly increase the chance of this fix
> being added to the 4.4 branch.

Backporting the fix onto the 4.4 and 4.3 branches is OK, the current code
doesn't make any sense.  But, yes, having a testcase would be better.

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[bigotp at acm dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

--- Comment #3 from Peter A. Bigot <bigotp at acm dot org> 2010-11-07 14:09:31 UTC ---
Created attachment 22308
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22308
Test case

This test case evokes the bug with the 16-bit msp430 target, which is not
integrated into gcc mainline.  When built with -O2, the copy from cal into tcal
is converted into a series of five one-word moves.  The copies for the values
at word offsets 2 (first half temperature_scale) and 4 (local_modbus_addr) are
apparently eliminated by some other optimization, but the copy for the last
half of temperature_scale hits the dse.c code.

In my case, I end up attempting to convert the value 5 to CCMode, instead of
the value 2 to HIMode, resulting in an ICE in trunc_int_for_mode at
explow.c:56.

I wasn't able to reproduce the ICE on a different architecture, and haven't
tried to check the generated code.  Seems that it's pretty dependent on the
back end.  

Hope this helps, and if not, that it's still ok to fix because it's clearly
wrong.

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-29 08:57:56 UTC ---
Author: ebotcazou
Date: Mon Nov 29 08:57:53 2010
New Revision: 167235

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=167235
Log:
    PR rtl-optimization/46337
    Backport from mainline
    2009-04-20  Ian Lance Taylor  <iant@google.com>

    * dse.c (replace_inc_dec): Reverse parameters to gen_int_mode.

Modified:
    branches/gcc-4_4-branch/gcc/ChangeLog
    branches/gcc-4_4-branch/gcc/dse.c

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.4.6

--- Comment #5 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-29 08:59:43 UTC ---
Fixed on 4.4 branch.

[Bug rtl-optimization/46337] dse.c:replace_inc_dec mis-use of gen_int_mode

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46337

--- Comment #6 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-29 11:03:07 UTC ---
Author: ebotcazou
Date: Mon Nov 29 11:03:03 2010
New Revision: 167238

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=167238
Log:
    PR rtl-optimization/46337
    Backport from mainline
    2009-04-20  Ian Lance Taylor  <iant@google.com>

    * dse.c (replace_inc_dec): Reverse parameters to gen_int_mode.

Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/dse.c