[Bug rtl-optimization/46777] New: [4.5/4.6 Regression] ICE: in rtl_verify_flow_info, at cfgrtl.c:2164 with -O -fgcse -fno-tree-dominator-opts -funroll-loops

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46777

           Summary: [4.5/4.6 Regression] ICE: in rtl_verify_flow_info, at
                    cfgrtl.c:2164 with -O -fgcse -fno-tree-dominator-opts
                    -funroll-loops
           Product: gcc
           Version: 4.6.0
            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 22610
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22610
reduced testcase

The ICE message looks similiar to PR46440 and PR46493, but this one fails in
trunk as well.

$ gcc -fgcse -O -fno-tree-dominator-opts -funroll-loops pr46777.c  
pr46777.c: In function 'little2_prologTok':
pr46777.c:39:1: error: verify_flow_info: Incorrect fallthru 67->68
pr46777.c:39:1: error: wrong insn in the fallthru edge
(barrier 585 579 594)
pr46777.c:39:1: internal compiler error: in rtl_verify_flow_info, at
cfgrtl.c:2164
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Backtrace:
(gdb) bt
#0  error (gmsgid=0x10ef838 "verify_flow_info: Incorrect fallthru %i->%i") at
/mnt/svn/gcc-trunk/gcc/diagnostic.c:747
#1  0x00000000005f6997 in rtl_verify_flow_info () at
/mnt/svn/gcc-trunk/gcc/cfgrtl.c:2162
#2  0x00000000005e6cd4 in verify_flow_info () at
/mnt/svn/gcc-trunk/gcc/cfghooks.c:257
#3  0x00000000005ebffa in outof_cfg_layout_mode () at
/mnt/svn/gcc-trunk/gcc/cfglayout.c:362
#4  0x00000000007eb69f in execute_one_pass (pass=0x1630b00) at
/mnt/svn/gcc-trunk/gcc/passes.c:1553
#5  0x00000000007eb965 in execute_pass_list (pass=0x1630b00) at
/mnt/svn/gcc-trunk/gcc/passes.c:1608
#6  0x00000000007eb977 in execute_pass_list (pass=0x1632200) at
/mnt/svn/gcc-trunk/gcc/passes.c:1609
#7  0x000000000092bb86 in tree_rest_of_compilation (fndecl=0x7ffff5ce3000) at
/mnt/svn/gcc-trunk/gcc/tree-optimize.c:422
#8  0x0000000000af13c2 in cgraph_expand_function (node=0x7ffff5ce2160) at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1508
#9  0x0000000000af399a in cgraph_expand_all_functions () at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1567
#10 cgraph_optimize () at /mnt/svn/gcc-trunk/gcc/cgraphunit.c:1827
#11 0x0000000000af3f1a in cgraph_finalize_compilation_unit () at
/mnt/svn/gcc-trunk/gcc/cgraphunit.c:1031
#12 0x0000000000508b8c in c_write_global_declarations () at
/mnt/svn/gcc-trunk/gcc/c-decl.c:9844
#13 0x00000000008d5580 in compile_file (argc=16, argv=0x7fffffffdc38) at
/mnt/svn/gcc-trunk/gcc/toplev.c:591
#14 do_compile (argc=16, argv=0x7fffffffdc38) at
/mnt/svn/gcc-trunk/gcc/toplev.c:1874
#15 toplev_main (argc=16, argv=0x7fffffffdc38) at
/mnt/svn/gcc-trunk/gcc/toplev.c:1937
#16 0x00007ffff6586bbd in __libc_start_main () from /lib/libc.so.6
#17 0x00000000004ef5f1 in _start ()


Tested revisions:
r167383 - crash
4.5 r166509 - crash
4.4 r166509 - OK