Resolve Travis LLVM 3.8.0 build error
Resolve Travis LLVM 3.8.0 build error


Former-commit-id: 01da87a5d1b3425293bf78de71adaa9ccccaf409
Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide