[Bug middle-end/85195] New: [8 Regression] ICE: verify_gimple failed: non-trivial conversion at assignment with -O -fno-tree-ccp --param=sccvn-max-scc-size=10

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85195

            Bug ID: 85195
           Summary: [8 Regression] ICE: verify_gimple failed: non-trivial
                    conversion at assignment with -O -fno-tree-ccp
                    --param=sccvn-max-scc-size=10
           Product: gcc
           Version: 8.0.1
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 43840
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43840&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O -fno-tree-ccp --param=sccvn-max-scc-size=10
testcase.c 
testcase.c: In function 'foo':
testcase.c:9:1: error: non-trivial conversion at assignment
 foo (void)
 ^~~
vector(1) __int128
__int128
_14 = _28;
during GIMPLE pass: forwprop
testcase.c:9:1: internal compiler error: verify_gimple failed
0xdb9ff9 verify_gimple_in_cfg(function*, bool)
        /repo/gcc-trunk/gcc/tree-cfg.c:5585
0xc36c93 execute_function_todo
        /repo/gcc-trunk/gcc/passes.c:1994
0xc375d9 execute_todo
        /repo/gcc-trunk/gcc/passes.c:2048
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-259070-checking-yes-rtl-df-extra-nobootstrap-pr85177-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/8.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-259070-checking-yes-rtl-df-extra-nobootstrap-pr85177-amd64
Thread model: posix
gcc version 8.0.1 20180404 (experimental) (GCC)