Convert assert(0) to llvm_unreachable

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149961 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 5449663..77cfc37 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -810,9 +810,7 @@
 MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
                                                 MachineBasicBlock *BB) const {
   switch (MI->getOpcode()) {
-  default:
-    assert(false && "Unexpected instr type to insert");
-    return NULL;
+  default: llvm_unreachable("Unexpected instr type to insert");
   case Mips::ATOMIC_LOAD_ADD_I8:
   case Mips::ATOMIC_LOAD_ADD_I8_P8:
     return EmitAtomicBinaryPartword(MI, BB, 1, Mips::ADDu);