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/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index ddfb912..1231afc 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -4578,8 +4578,7 @@
   DebugLoc dl = N->getDebugLoc();
   switch (N->getOpcode()) {
   default:
-    assert(false && "Do not know how to custom type legalize this operation!");
-    return;
+    llvm_unreachable("Do not know how to custom type legalize this operation!");
   case ISD::VAARG: {
     if (!TM.getSubtarget<PPCSubtarget>().isSVR4ABI()
         || TM.getSubtarget<PPCSubtarget>().isPPC64())