Subzero: Prune unreachable nodes after constructing the Cfg.

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.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the CfgNode class, including the complexities
@@ skipping 51 matching lines @@
   for (Inst &I : Insts)
     I.renumber(Func);
   InstCountEstimate = Func->getNextInstNumber() - FirstNumber;
 }
 
 // When a node is created, the OutEdges are immediately known, but the
 // InEdges have to be built up incrementally.  After the CFG has been
 // constructed, the computePredecessors() pass finalizes it by
 // creating the InEdges list.
 void CfgNode::computePredecessors() {
-  OutEdges = Insts.rbegin()->getTerminatorEdges();
   for (CfgNode *Succ : OutEdges)
     Succ->InEdges.push_back(this);
 }
 
+void CfgNode::computeSuccessors() {
+  OutEdges = Insts.rbegin()->getTerminatorEdges();
+}
+
 // This does part 1 of Phi lowering, by creating a new dest variable
 // for each Phi instruction, replacing the Phi instruction's dest with
 // that variable, and adding an explicit assignment of the old dest to
 // the new dest.  For example,
 //   a=phi(...)
 // changes to
 //   "a_phi=phi(...); a=a_phi".
 //
 // This is in preparation for part 2 which deletes the Phi
 // instructions and appends assignment instructions to predecessor
@@ skipping 511 matching lines @@
   // set bits for global variables upon block entry.  We validate this
   // by shrinking the Live vector and then testing it against the
   // pre-shrunk version.  (The shrinking is required, but the
   // validation is not.)
   LivenessBV LiveOrig = Live;
   Live.resize(Liveness->getNumGlobalVars());
   // Non-global arguments in the entry node are allowed to be live on
   // entry.
   bool IsEntry = (Func->getEntryNode() == this);
   if (!(IsEntry || Live == LiveOrig)) {
-    // This is a fatal liveness consistency error.  Print some
-    // diagnostics and abort.
-    Ostream &Str = Func->getContext()->getStrDump();
-    Func->resetCurrentNode();
-    Str << "LiveOrig-Live =";
-    for (SizeT i = Live.size(); i < LiveOrig.size(); ++i) {
-      if (LiveOrig.test(i)) {
-        Str << " ";
-        Liveness->getVariable(i, this)->dump(Func);
+    if (ALLOW_DUMP) {
+      // This is a fatal liveness consistency error.  Print some
+      // diagnostics and abort.
+      Ostream &Str = Func->getContext()->getStrDump();
+      Func->resetCurrentNode();
+      Str << "LiveOrig-Live =";
+      for (SizeT i = Live.size(); i < LiveOrig.size(); ++i) {
+        if (LiveOrig.test(i)) {
+          Str << " ";
+          Liveness->getVariable(i, this)->dump(Func);
+        }
       }
+      Str << "\n";
     }
-    Str << "\n";
-    llvm_unreachable("Fatal inconsistency in liveness analysis");
+    llvm::report_fatal_error("Fatal inconsistency in liveness analysis");
   }
 
   bool Changed = false;
   LivenessBV &LiveIn = Liveness->getLiveIn(this);
   // Add in current LiveIn
   Live |= LiveIn;
   // Check result, set LiveIn=Live
   SizeT &PrevNumNonDeadPhis = Liveness->getNumNonDeadPhis(this);
   bool LiveInChanged = (Live != LiveIn);
   Changed = (NumNonDeadPhis != PrevNumNonDeadPhis || LiveInChanged);
@@ skipping 563 matching lines @@
       if (!First)
         Str << ", ";
       First = false;
       Str << "%" << I->getName();
     }
     Str << "\n";
   }
 }
 
 } // end of namespace Ice