[Bug rtl-optimization/70061] New: [6 Regression] ICE: SIGSEGV in delete_insn_chain() with -mstringop-strategy=libcall

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70061

            Bug ID: 70061
           Summary: [6 Regression] ICE: SIGSEGV in delete_insn_chain()
                    with -mstringop-strategy=libcall
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
            Target: i686-pc-linux-gnu

Created attachment 37851
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37851&action=edit
reduced testcase

Compiler output:
$ i686-pc-linux-gnu-gcc -Os -fno-tree-coalesce-vars -mstringop-strategy=libcall
testcase.c testcase.c: In function 'foo':
testcase.c:4:1: note: The ABI for passing parameters with 32-byte alignment has
changed in GCC 4.6
 foo(v8si c, v8si d)
 ^~~
testcase.c:4:1: warning: AVX vector argument without AVX enabled changes the
ABI [-Wpsabi]
testcase.c:10:1: internal compiler error: Segmentation fault
 }
 ^
0xbb842f crash_signal
        /repo/gcc-trunk/gcc/toplev.c:335
0x72f55d safe_as_a<rtx_insn*, rtx_def>
        /repo/gcc-trunk/gcc/rtl.h:844
0x72f55d delete_insn_chain(rtx_def*, rtx_def*, bool)
        /repo/gcc-trunk/gcc/cfgrtl.c:246
0x72fa9f rtl_merge_blocks
        /repo/gcc-trunk/gcc/cfgrtl.c:885
0x7204d5 merge_blocks(basic_block_def*, basic_block_def*)
        /repo/gcc-trunk/gcc/cfghooks.c:774
0x13d5df4 merge_blocks_move
        /repo/gcc-trunk/gcc/cfgcleanup.c:774
0x13d5df4 try_optimize_cfg
        /repo/gcc-trunk/gcc/cfgcleanup.c:2787
0x13d5df4 cleanup_cfg(int)
        /repo/gcc-trunk/gcc/cfgcleanup.c:3028
0x71c0c2 execute
        /repo/gcc-trunk/gcc/cfgexpand.c:6467
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

$ i686-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-i686/bin/i686-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-233911-checking-yes-rtl-df-nographite-i686/bin/../libexec/gcc/i686-pc-linux-gnu/6.0.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-checking=yes,rtl,df --without-cloog --without-ppl --without-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=i686-pc-linux-gnu --with-ld=/usr/bin/i686-pc-linux-gnu-ld
--with-as=/usr/bin/i686-pc-linux-gnu-as --with-sysroot=/usr/i686-pc-linux-gnu
--disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-233911-checking-yes-rtl-df-nographite-i686
Thread model: posix
gcc version 6.0.0 20160302 (experimental) (GCC) 


Tested revisions:
trunk r233911 - FAIL
trunk r233861 - FAIL
5-branch r233800 - OK