[Bug rtl-optimization/48237] New: [4.6/4.7 Regression] ICE: in final_scan_insn, at final.c:2651 with -fselective-scheduling2 -mtune=core2

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48237

           Summary: [4.6/4.7 Regression] ICE: in final_scan_insn, at
                    final.c:2651 with -fselective-scheduling2 -mtune=core2
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 23750
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23750
reduced testcase

Compiler output:
$ gcc -O -fcaller-saves -fschedule-insns2 -fselective-scheduling2 -mtune=core2
testcase.c
testcase.c: In function 'foo':
testcase.c:19:1: internal compiler error: in final_scan_insn, at final.c:2651
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

The failing assert is:
#ifdef HAVE_ATTR_length
        /* This instruction should have been split in shorten_branches,
           to ensure that we would have valid length info for the
           splitees.  */
        gcc_unreachable ();
#endif

Tested revisions:
r171265 - crash
4.6 r170955 - crash
4.5 r170955 - OK