Replace several 'assert(false' with 'llvm_unreachable' or fold a condition into the assert.

llvm-svn: 225160
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 5a6ea8e..74769e5 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9735,7 +9735,7 @@
         } else if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Val)) {
           StoreInt|= C->getValueAPF().bitcastToAPInt().zext(StoreBW);
         } else {
-          assert(false && "Invalid constant element type");
+          llvm_unreachable("Invalid constant element type");
         }
       }