Subzero: Change -asm-verbose output to print more useful info.

src/IceCfgNode.cpp

 //===- subzero/src/IceCfgNode.cpp - Basic block (node) implementation -----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 960 matching lines @@
 }
 
 } // end of anonymous namespace
 
 void CfgNode::emit(Cfg *Func) const {
   if (!BuildDefs::dump())
     return;
   Func->setCurrentNode(this);
   Ostream &Str = Func->getContext()->getStrEmit();
   Liveness *Liveness = Func->getLiveness();
-  bool DecorateAsm =
+  const bool DecorateAsm =
       Liveness && Func->getContext()->getFlags().getDecorateAsm();
   Str << getAsmName() << ":\n";
   // LiveRegCount keeps track of the number of currently live variables that
   // each register is assigned to. Normally that would be only 0 or 1, but the
   // register allocator's AllowOverlap inference allows it to be greater than 1
   // for short periods.
   CfgVector<SizeT> LiveRegCount(Func->getTarget()->getNumRegisters());
   if (DecorateAsm) {
     constexpr bool IsLiveIn = true;
     emitRegisterUsage(Str, Func, this, IsLiveIn, LiveRegCount);
+    if (getInEdges().size()) {
+      Str << "\t\t\t\t# preds=";
+      bool First = true;
+      for (CfgNode *I : getInEdges()) {
+        if (!First)
+          Str << ",";
+        First = false;
+        Str << I->getAsmName();
+      }
+      Str << "\n";
+    }
+    if (getLoopNestDepth()) {
+      Str << "\t\t\t\t# loop depth=" << getLoopNestDepth() << "\n";
+    }
   }
 
   for (const Inst &I : Phis) {
     if (I.isDeleted())
       continue;
     // Emitting a Phi instruction should cause an error.
     I.emit(Func);
   }
   for (const Inst &I : Insts) {
     if (I.isDeleted())
@@ skipping 351 matching lines @@
   InstIntrinsicCall *Inst = InstIntrinsicCall::create(
       Func, 5, Func->makeVariable(IceType_i64), RMWI64Name, Info->Info);
   Inst->addArg(AtomicRMWOp);
   Inst->addArg(Counter);
   Inst->addArg(One);
   Inst->addArg(OrderAcquireRelease);
   Insts.push_front(Inst);
 }
 
 } // end of namespace Ice