[Bug debug/47994] New: -fcompare-debug failure with -O2 -fpeel-loops -fno-rerun-cse-after-loop -fno-tree-loop-optimize -fno-web

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47994

           Summary: -fcompare-debug failure with -O2 -fpeel-loops
                    -fno-rerun-cse-after-loop -fno-tree-loop-optimize
                    -fno-web
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
                CC: aoliva@gcc.gnu.org
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 23548
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23548
reduced testcase

Compiler output:
$ gcc -O2 -fpeel-loops -fno-rerun-cse-after-loop -fno-tree-loop-optimize
-fno-web -fcompare-debug testcase.c  
gcc: error: testcase.c: -fcompare-debug failure (length)

$ diff testcase.*gkd
34a35
> (note# 0 0 NOTE_INSN_DELETED)
37,44d37
<                 (plus:SI (reg/v:SI 5 di [orig:64 j ] [64])
<                     (const_int 1 [0x1])))
<             (clobber (reg:CC 17 flags))
<         ]) testcase.c:8# {*addsi_1}
<      (expr_list:REG_UNUSED (reg:CC 17 flags)
<         (nil)))
< (insn# 0 0 2 (parallel [
<             (set (reg:SI 5 di [orig:62 prephitmp.5 ] [62])
54c47
<                     (const_int 80 [0x50])))
---
>                     (const_int 81 [0x51])))

Tested revisions:
r170674 - fail
4.5 r170013 - fail