[Bug debug/46799] New: -fcompare-debug failure (length) with -ftree-parallelize-loops=2 -fno-tree-dce

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46799

           Summary: -fcompare-debug failure (length) with
                    -ftree-parallelize-loops=2 -fno-tree-dce
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: zso...@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 22630
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22630
reduced testcase

Compiler output:
$ gcc -O -ftree-parallelize-loops=2 -fno-tree-dce -ftree-pre -fcompare-debug
pr46799.c 
gcc: error: pr46799.c: -fcompare-debug failure (length)
$ diff pr46799.*gkd
204c204
<         (reg:DI 6 bp))# {*pushdi2_rex64}
---
>         (reg:DI 6 bp)) pr46799.c:1# {*pushdi2_rex64}
208c208
<         (reg:DI 3 bx))# {*pushdi2_rex64}
---
>         (reg:DI 3 bx)) pr46799.c:1# {*pushdi2_rex64}
217c217
<         ])# {pro_epilogue_adjust_stack_di_add}
---
>         ]) pr46799.c:1# {pro_epilogue_adjust_stack_di_add}
227c227
<                 (const_int 8 [0x8])) [ .paral_data_load.11_3->D.xxxx+0 S4
A32])) pr46799.c:33554427# {*movsi_internal}
---
>                 (const_int 8 [0x8])) [ .paral_data_load.11_3->D.xxxx+0 S4 
> A32])) pr46799.c:1# {*movsi_internal}


Tested revisions:
r167424 - fail
r153685 - OK
4.5 r166509 - fail