https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71146
--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- trippels@gcc2-power8 http % cat Http2Session.ii typedef enum {} nsresult; struct A { virtual void SetConnection(); }; struct B { virtual nsresult OnReadSegment(const char *, int, int *) = 0; }; struct C : A, B { nsresult OnReadSegment(const char *, int, int *); void FlushOutputQueue(); B *mSegmentReader; }; void C::FlushOutputQueue() { if (!mSegmentReader) return; mSegmentReader->OnReadSegment(0, 0, 0); } nsresult C::OnReadSegment(const char *, int, int *) { FlushOutputQueue(); mSegmentReader = 0; OnReadSegment(0, 0, 0); } trippels@gcc2-power8 http % g++ -O3 -c Http2Session.ii Http2Session.ii: In member function ‘virtual nsresult C::OnReadSegment(const char*, int, int*)’: Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments mSegmentReader->OnReadSegment(0, 0, 0); ^ __builtin_unreachable (adjusted_this.9_275, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.10_280, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.11_290, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.12_295, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.13_300, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.14_305, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.15_317, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.16_322, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.17_327, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.18_332, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.19_337, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.20_342, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.21_356, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.22_361, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.23_366, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.24_371, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.25_376, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.26_381, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.27_386, 0B, 0, 0B); Http2Session.ii:16:41: error: __builtin_unreachable or __builtin_trap call with arguments __builtin_unreachable (adjusted_this.28_391, 0B, 0, 0B); Http2Session.ii:16:41: 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