Subzero: Improve performance of liveness analysis and live range construction.

src/IceLiveness.cpp

Index: src/IceLiveness.cpp
diff --git a/src/IceLiveness.cpp b/src/IceLiveness.cpp
index 9b58b4339f38b019c4f06363f67a88559ddd3b4d..e992d2811453be480a6d78785358996faa72a6c2 100644
--- a/src/IceLiveness.cpp
+++ b/src/IceLiveness.cpp
@@ -32,6 +32,7 @@ void Liveness::init() {
   // Initialize most of the container sizes.
   SizeT NumVars = Func->getVariables().size();
   SizeT NumNodes = Func->getNumNodes();
+  VariablesMetadata *VMetadata = Func->getVMetadata();
   Nodes.resize(NumNodes);
   VarToLiveMap.resize(NumVars);
   if (Mode == Liveness_Intervals)
@@ -41,10 +42,10 @@ void Liveness::init() {
   // block.
   for (SizeT i = 0; i < NumVars; ++i) {
     Variable *Var = Func->getVariables()[i];
-    if (Func->getVMetadata()->isMultiBlock(Var)) {
+    if (VMetadata->isMultiBlock(Var)) {
       ++NumGlobals;
     } else {
-      SizeT Index = Func->getVMetadata()->getLocalUseNode(Var)->getIndex();
+      SizeT Index = VMetadata->getLocalUseNode(Var)->getIndex();
       ++Nodes[Index].NumLocals;
     }
   }
@@ -64,11 +65,11 @@ void Liveness::init() {
     Variable *Var = Func->getVariables()[i];
     SizeT VarIndex = Var->getIndex();
     SizeT LiveIndex;
-    if (Func->getVMetadata()->isMultiBlock(Var)) {
+    if (VMetadata->isMultiBlock(Var)) {
       LiveIndex = TmpNumGlobals++;
       LiveToVarMap[LiveIndex] = Var;
     } else {
-      SizeT NodeIndex = Func->getVMetadata()->getLocalUseNode(Var)->getIndex();
+      SizeT NodeIndex = VMetadata->getLocalUseNode(Var)->getIndex();
       LiveIndex = Nodes[NodeIndex].NumLocals++;
       Nodes[NodeIndex].LiveToVarMap[LiveIndex] = Var;
       LiveIndex += NumGlobals;