Convert some assert(0) to llvm_unreachable or fold an 'if' condition into the assert.

llvm-svn: 211254
diff --git a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
index ea6367a..1c95e06 100644
--- a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
@@ -1538,14 +1538,13 @@
   int NewOp = opc;
   if (isPredicated(NewOp) && isPredicatedNew(NewOp)) { // Get predicate old form
     NewOp = Hexagon::getPredOldOpcode(NewOp);
-    if (NewOp < 0)
-      assert(0 && "Couldn't change predicate new instruction to its old form.");
+    assert(NewOp >= 0 &&
+           "Couldn't change predicate new instruction to its old form.");
   }
 
   if (isNewValueStore(NewOp)) { // Convert into non-new-value format
     NewOp = Hexagon::getNonNVStore(NewOp);
-    if (NewOp < 0)
-      assert(0 && "Couldn't change new-value store to its old form.");
+    assert(NewOp >= 0 && "Couldn't change new-value store to its old form.");
   }
   return NewOp;
 }