Subzero: Implement InstList in terms of llvm::ilist<> .

src/IceCfg.cpp

Index: src/IceCfg.cpp
diff --git a/src/IceCfg.cpp b/src/IceCfg.cpp
index 8e73499c46a8161c974510a1d621c382f8cef2ad..b461d682e090b8e79993b87a328eef93b51c0144 100644
--- a/src/IceCfg.cpp
+++ b/src/IceCfg.cpp
@@ -318,7 +318,8 @@ bool Cfg::validateLiveness() const {
   Ostream &Str = Ctx->getStrDump();
   for (CfgNode *Node : Nodes) {
     Inst *FirstInst = NULL;
-    for (Inst *Inst : Node->getInsts()) {
+    for (auto Inst = Node->getInsts().begin(), E = Node->getInsts().end();
+         Inst != E; ++Inst) {
       if (Inst->isDeleted())
         continue;
       if (FirstInst == NULL)
@@ -337,7 +338,8 @@ bool Cfg::validateLiveness() const {
           // temporary may be live at the end of the previous block,
           // and if it is also assigned in the first instruction of
           // this block, the adjacent live ranges get merged.
-          if (Inst != FirstInst && !Inst->isDestNonKillable() &&
+          if (static_cast<class Inst *>(Inst) != FirstInst &&
+              !Inst->isDestNonKillable() &&
               Dest->getLiveRange().containsValue(InstNumber - 1, IsDest))
             Invalid = true;
           if (Invalid) {