Fixes to be upstreamed - 10

1. add support for DumpRegUsage in NPM (currntly I have added it in the destructor of RegisterUsageInfo, this seems to work but im not sure if it has any side effects)

Author: vikramRH

llvm/include/llvm/CodeGen/RegisterUsageInfo.h

@@ -34,6 +34,8 @@ class TargetMachine;
 
 class PhysicalRegisterUsageInfo {
 public:
+
+  ~PhysicalRegisterUsageInfo();
   /// Set TargetMachine which is used to print analysis.
   void setTargetMachine(const TargetMachine &TM);
 

llvm/lib/CodeGen/RegisterUsageInfo.cpp

@@ -56,6 +56,13 @@ bool PhysicalRegisterUsageInfo::doFinalization(Module &M) {
   return false;
 }
 
+PhysicalRegisterUsageInfo::~PhysicalRegisterUsageInfo() {
+    if (DumpRegUsage)
+      print(errs());
+    
+    RegMasks.shrink_and_clear();
+}
+
 void PhysicalRegisterUsageInfo::storeUpdateRegUsageInfo(
     const Function &FP, ArrayRef<uint32_t> RegMask) {
   RegMasks[&FP] = RegMask;