[Bug tree-optimization/46355] New: [4.5/4.6 Regression] ICE: SIGSEGV in create_preheader (cfgloopmanip.c:1336) with -O -fstrict-overflow -ftree-loop-distribution

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46355

           Summary: [4.5/4.6 Regression] ICE: SIGSEGV in create_preheader
                    (cfgloopmanip.c:1336) with -O -fstrict-overflow
                    -ftree-loop-distribution
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
                CC: spop@gcc.gnu.org
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 22318
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22318
reduced testcase

I was reducing a testcase that had the same backtrace as PR45948, but the
reduced testcase turned out to cause a bit different ICE. It also started
crashing at different revision.
I don't know how much is this related to PR45948 and PR45199.

Related valgrind output:
$ gcc -O -ftree-loop-distribution -fstrict-overflow pr46355.c
==20450== Invalid read of size 8
==20450==    at 0x59BF64: create_preheader (cfgloopmanip.c:1336)
==20450==    by 0x8D845D: distribute_loop (tree-loop-distribution.c:180)
==20450==    by 0x8D8A0C: tree_loop_distribution
(tree-loop-distribution.c:1201)
==20450==    by 0x79980E: execute_one_pass (passes.c:1560)
==20450==    by 0x799AB4: execute_pass_list (passes.c:1615)
==20450==    by 0x799AC6: execute_pass_list (passes.c:1616)
==20450==    by 0x799AC6: execute_pass_list (passes.c:1616)
==20450==    by 0x8E6715: tree_rest_of_compilation (tree-optimize.c:422)
==20450==    by 0xAB6601: cgraph_expand_function (cgraphunit.c:1493)
==20450==    by 0xAB8BC9: cgraph_optimize (cgraphunit.c:1552)
==20450==    by 0xAB9129: cgraph_finalize_compilation_unit (cgraphunit.c:1016)
==20450==    by 0x4AC9AB: c_write_global_declarations (c-decl.c:9831)
==20450==  Address 0x8 is not stack'd, malloc'd or (recently) free'd
==20450== 
pr46355.c: In function 'foo':
pr46355.c:2:1: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
r166414 - crash
r153685 - crash
4.5 r165781 - crash
4.4 r165754 - OK