Subzero: Control whether deleted instructions are retained.

src/IceCfg.h

 //===- subzero/src/IceCfg.h - Control flow graph ----------------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 167 matching lines @@
   /// Returns true if Var is a global variable that is used by the profiling
   /// code.
   static bool isProfileGlobal(const VariableDeclaration &Var);
 
   /// Passes over the CFG.
   void translate();
   /// After the CFG is fully constructed, iterate over the nodes and compute the
   /// predecessor and successor edges, in the form of CfgNode::InEdges[] and
   /// CfgNode::OutEdges[].
   void computeInOutEdges();
+  /// Renumber the non-deleted instructions in the Cfg.  This needs to be done
+  /// in preparation for live range analysis.  The instruction numbers in a
+  /// block must be monotonically increasing.  The range of instruction numbers
+  /// in a block, from lowest to highest, must not overlap with the range of any
+  /// other block.
+  ///
+  /// Also, if the configuration specifies to do so, remove/unlink all deleted
+  /// instructions from the Cfg, to speed up later passes over the instructions.
   void renumberInstructions();
   void placePhiLoads();
   void placePhiStores();
   void deletePhis();
   void advancedPhiLowering();
   void reorderNodes();
   void shuffleNodes();
 
   /// Scan allocas to determine whether we need to use a frame pointer.
   /// If SortAndCombine == true, merge all the fixed-size allocas in the
@@ skipping 113 matching lines @@
 
 public:
   static void TlsInit() { CfgAllocatorTraits::init(); }
 };
 
 template <> Variable *Cfg::makeVariable<Variable>(Type Ty);
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICECFG_H