[Bug middle-end/71146] New: [7 Regression] error: __builtin_unreachable or __builtin_trap call with arguments

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71146

            Bug ID: 71146
           Summary: [7 Regression] error: __builtin_unreachable or
                    __builtin_trap call with arguments
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
  Target Milestone: ---

Created attachment 38496
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38496&action=edit
unreduced testcase

trippels@gcc2-power8 ~ % ~/gcc_test/usr/local/bin/g++ -w -O3 -c Http2Session.ii
/home/trippels/gecko-dev/netwerk/protocol/http/Http2Session.cpp: In member
function ‘nsresult mozilla::net::Http2Session::BufferOutput(const char*,
uint32_t, uint32_t*)’:
/home/trippels/gecko-dev/netwerk/protocol/http/Http2Session.cpp:2898:62: error:
__builtin_unreachable or __builtin_trap call with arguments
     rv = mSegmentReader->OnReadSegment(buf, count, countRead);
                                                              ^
__builtin_unreachable (adjusted_this.1907_86, _52, avail_47, &countRead);
/home/trippels/gecko-dev/netwerk/protocol/http/Http2Session.cpp:2898:62:
internal compiler error: verify_gimple failed
0x10b1c447 verify_gimple_in_cfg(function*, bool)
        ../../gcc/gcc/tree-cfg.c:5166
0x109be22f execute_function_todo
        ../../gcc/gcc/passes.c:1964
0x109bf083 do_per_function
        ../../gcc/gcc/passes.c:1648
0x109bf39f execute_todo
        ../../gcc/gcc/passes.c:2016

Reducing...