Support for target dependent Hexagon VLIW packetizer.

This patch creates and optimizes packets as per Hexagon ISA rules.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156109 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Hexagon/HexagonMCInstLower.cpp b/lib/Target/Hexagon/HexagonMCInstLower.cpp
index fbb331b..70bddcc 100644
--- a/lib/Target/Hexagon/HexagonMCInstLower.cpp
+++ b/lib/Target/Hexagon/HexagonMCInstLower.cpp
@@ -49,7 +49,7 @@
     switch (MO.getType()) {
     default:
       MI->dump();
-      assert(0 && "unknown operand type");
+      llvm_unreachable("unknown operand type");
     case MachineOperand::MO_Register:
       // Ignore all implicit register operands.
       if (MO.isImplicit()) continue;