[Bug c++/86871] New: ICE: gimple check: expected gimple_assign(error_mark), have gimple_call(trunc_mod_expr) in gimple_assign_lhs, at gimple.h:2462

[slyfox at inbox dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86871

            Bug ID: 86871
           Summary: ICE: gimple check: expected gimple_assign(error_mark),
                    have gimple_call(trunc_mod_expr) in gimple_assign_lhs,
                    at gimple.h:2462
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at inbox dot ru
  Target Milestone: ---

Created attachment 44511
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44511&action=edit
a.cc

Original bug report where g++ crashes when compiling opencv-3.4.1:
    https://bugs.gentoo.org/657060

Also reproducible on gcc-master:

$ ./gcc/xg++ -B ./gcc -c /tmp/a.cc -O2 -march=bdver4 -ftree-vectorize
during GIMPLE pass: vect
/tmp/a.cc: In function 'void fn1()':
/tmp/a.cc:34:6: internal compiler error: gimple check: expected
gimple_assign(error_mark), have gimple_call(trunc_mod_expr) in
gimple_assign_lhs, at gimple.h:2462
 void fn1() {
      ^~~
0x7f822fff979a __libc_start_main
        ../csu/libc-start.c:308
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.

$ ./gcc/xg++ -v
Using built-in specs.
COLLECT_GCC=./gcc/xg++
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --enable-languages=c,c++ --disable-bootstrap
--with-multilib-list=m64
--prefix=/home/slyfox/dev/git/gcc-x86_64/../gcc-native-quick-installed
--disable-nls CFLAGS='-O0  ' CXXFLAGS='-O0  '
--with-sysroot=/usr/x86_64-HEAD-linux-gnu
Thread model: posix
gcc version 9.0.0 20180806 (experimental) (GCC)