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

llvm-svn: 225160
diff --git a/llvm/lib/CodeGen/JumpInstrTables.cpp b/llvm/lib/CodeGen/JumpInstrTables.cpp
index 20f775c..bc796ed 100644
--- a/llvm/lib/CodeGen/JumpInstrTables.cpp
+++ b/llvm/lib/CodeGen/JumpInstrTables.cpp
@@ -117,8 +117,8 @@
     if (!isa<GlobalAlias>(C))
       C->replaceUsesOfWithOnConstant(GV, V, U);
   } else {
-    assert(false && "The Use of a Function symbol is neither an instruction nor"
-                    " a constant");
+    llvm_unreachable("The Use of a Function symbol is neither an instruction "
+                     "nor a constant");
   }
 
   return true;