Subzero: Improve usability of liveness-related tools.

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 269 matching lines @@
 
   virtual void doAddressOptLoad() {}
   virtual void doAddressOptStore() {}
   virtual void doMockBoundsCheck(Operand *) {}
   virtual void randomlyInsertNop(float Probability,
                                  RandomNumberGenerator &RNG) = 0;
   /// This gives the target an opportunity to post-process the lowered expansion
   /// before returning.
   virtual void postLower() {}
 
-  /// Find two-address non-SSA instructions and set the DestNonKillable flag to
-  /// keep liveness analysis consistent.
-  void inferTwoAddress();
+  /// Find (non-SSA) instructions where the Dest variable appears in some source
+  /// operand, and set the IsDestRedefined flag.  This keeps liveness analysis
+  /// consistent.
+  void markRedefinitions();
 
   /// Make a pass over the Cfg to determine which variables need stack slots and
   /// place them in a sorted list (SortedSpilledVariables). Among those, vars,
   /// classify the spill variables as local to the basic block vs global
   /// (multi-block) in order to compute the parameters GlobalsSize and
   /// SpillAreaSizeBytes (represents locals or general vars if the coalescing of
   /// locals is disallowed) along with alignments required for variables in each
   /// area. We rely on accurate VMetadata in order to classify a variable as
   /// global vs local (otherwise the variable is conservatively global). The
   /// in-args should be initialized to 0.
@@ skipping 38 matching lines @@
 
   /// Make a call to an external helper function.
   InstCall *makeHelperCall(const IceString &Name, Variable *Dest,
                            SizeT MaxSrcs);
 
   void
   _bundle_lock(InstBundleLock::Option BundleOption = InstBundleLock::Opt_None) {
     Context.insert(InstBundleLock::create(Func, BundleOption));
   }
   void _bundle_unlock() { Context.insert(InstBundleUnlock::create(Func)); }
-  void _set_dest_nonkillable() {
-    Context.getLastInserted()->setDestNonKillable();
-  }
+  void _set_dest_redefined() { Context.getLastInserted()->setDestRedefined(); }
 
   bool shouldOptimizeMemIntrins();
 
   Cfg *Func;
   GlobalContext *Ctx;
   bool HasComputedFrame = false;
   bool CallsReturnsTwice = false;
   /// StackAdjustment keeps track of the current stack offset from its natural
   /// location, e.g. as arguments are pushed for a function call or as
   /// fixed-size alloca instructions are executed in the entry block.
@@ skipping 90 matching lines @@
   virtual void lower() {}
 
 protected:
   explicit TargetHeaderLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H