[Bug sanitizer/88215] New: UBSAN: Internal compiler error with attribute(unused)

[orgads at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88215

            Bug ID: 88215
           Summary: UBSAN: Internal compiler error with attribute(unused)
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: orgads at gmail dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

> cat err.cpp

void foo()
{
    unsigned a = 2, __attribute__ ((unused)) b = 1;
    unsigned f = a/b;
}

> g++ -fsanitize=undefined -w -O0 -c err.cpp

err.cpp: In function 'void foo()':
err.cpp:4:20: internal compiler error: in ubsan_instrument_division, at
c-family/c-ubsan.c:48
     unsigned f = a/b;

It doesn't happen if the variable is declared separately:

unsigned __attribute__ ((unused)) b = 1;

or

__attribute__ ((unused)) unsigned b = 1;

Looks similar to bug 80348.