Switch the representation of the location in instruction from
being a TrackingVH<MDNode> to a NewDebugLoc, shrinking 
sizeof(Instruction) a lot, and providing clients the ability
to deal with locations in terms of NewDebugLoc instead of
having to deal with Metadata.  This is still fully compatible
with all clients that *do* use MDNodes for everything of
course.

No functionality change.

llvm-svn: 100088
diff --git a/llvm/lib/VMCore/Instruction.cpp b/llvm/lib/VMCore/Instruction.cpp
index ee75a97..a37fe07 100644
--- a/llvm/lib/VMCore/Instruction.cpp
+++ b/llvm/lib/VMCore/Instruction.cpp
@@ -22,7 +22,7 @@
 
 Instruction::Instruction(const Type *ty, unsigned it, Use *Ops, unsigned NumOps,
                          Instruction *InsertBefore)
-  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0), DbgInfo(0) {
+  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
   // Make sure that we get added to a basicblock
   LeakDetector::addGarbageObject(this);
 
@@ -36,7 +36,7 @@
 
 Instruction::Instruction(const Type *ty, unsigned it, Use *Ops, unsigned NumOps,
                          BasicBlock *InsertAtEnd)
-  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0), DbgInfo(0) {
+  : User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
   // Make sure that we get added to a basicblock
   LeakDetector::addGarbageObject(this);